Today you spent learning all about Geology, the study of Earth! Mr. Mashenko’s presentation on Geology was very interesting an informative! Tonight your blog has two parts. Please read through the entire blog and draft in word to ensure you are doing your best work!

Part A:
Answer one of the following questions. Your response for this part should be at least one paragraph. Use the notes and information you gathered in class to help you with these questions.

* What can rocks tell us about the history of the Earth?
* How do geologists draw conclusions about the past?
* How do glaciers leave souvenirs? (Be sure to include examples, you may need to do extra research. Check out the Geology tab for help!)

Part B
Choose one of the following two topics. Spend 10 minutes researching using the following links (or your own, be sure to include the websites you used!). Write a one paragraph summary of your topic.

*Mohs Hardness Scale
*Stalagmite and stalactite

Your entire response must be atleast 2 paragraphs. Try to elaborate on your response with as many supporting details as possible. Remember to draft your response in Word first. Re-read your response for spelling, correct punctuation, and complete sentences.

 

Geology Links:
http://www.rocksforkids.com/RFK/identification.html
http://www.childrensmuseum.org/geomysteries/cube/b2.html
http://science.howstuffworks.com/environmental/earth/geology/stalactite-stalagmite1.htm
http://dsc.discovery.com/videos/assignment-discovery-shorts-stalactites-and-stalagmites.html
Jessica
5/2/2012 05:50:31 am

Rocks can tell us about the earth because, a rock can come from the middle of the earth you never know. If they were to get samples From the inner core they could tell what was In there and so on. In some rocks there are fossils. The fossils can tell us what kind of animal fossil is in there and maybe tell how old the rock and the fossil is. It could give them a big clue about extinct animals we never got to see.

A stalagmite is a rock typed thing that hangs from the ceiling. The stalagctite sticks up from the floor. They are almost alike except that one is on the floor one is on the ceiling. They both form the same way. One takes water droplits from the cave top one takes water rolling down off the cave top and stops it.

The website I used www.jimloy.com/geology

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ashley
5/2/2012 05:59:07 am

Part A- Rocks can tell us a lot about the history of the Earth. They can tell us where they came from and what happened to it over the years. The rocks can tell us about the history by the shape, size, color or texture of the rock. Sometimes you wonder...Where did this rock come from? Well, it probable came from the Ice Age.

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ashley
5/2/2012 05:59:21 am

Part B- For my summary, the topic I chose was Mohs Hardness Scale. Mohs Hardness Scale is used to compare the hardness of any mineral. The higher the number on the scale the harder the mineral is. The Mohs Hardness Scale's numbers are 1-10. A number 1 is a rock called Talc. Talc is the softest mineral on the Mohs Scale. A number 10 is a rock called a diamond. A diamond is the hardest of all minerals! It is forty times harder than Talc!

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Ivan F
5/2/2012 06:00:21 am


Rocks can tell us many things about our earth. Rocks were even made into tools by the first people that lived during the stone age. Rocks can date back to when the earth was fully formed. So of them can tell you about the events that they faced. Fossils can show us the different creatures that lived long ago. The fossils also cant tell if it was a sea creature or a land animal. If it was a animal from the ocean you could probably tell that where you found it was a ocean millions and millions of years ago.
The Mohs hardness scale is a scale that tells the hardness of a rock or mineral. It reaches from 1(the weakest) to ten (The strongest). The only mineral that reaches 10 is diamond. Its so strong that its not even going to scratch using car keys. The easiest way to cut a diamond in half is by using a laser. The weakest minerals or rock can break or scratch very easily.

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Sean S
5/2/2012 06:18:52 am

-What can rocks tell us about the history of the earth
Well one big part of how rocks can tell us about the history of the earth are the fossils inside and outside the rock. That can tell us alot about the animal. The reason I say this is because if the bones get stuck in the rocks and we take the bones out we can tell almost anything about that type of animal. Like when the first died if they evoled or when they became excint. It also tells us about life before our time. I know that Matts dad brought in a rock that looked like a spear head, his dad said that the cave men could have used that for hunting.
I really don’t get what your asking me to do for part B. Am I supposed to do 1 or 2 paragraphs. And am I supposed to do the difference between Stalagmite and stalactite, can you explain it to me and then I’ll do it at x period. Thanks have a nice night.

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Hanna S.
5/2/2012 06:23:16 am

Rocks can show us a lot a lot about the history of the Earth. They can show us who once lived on the Earth before us. Some sedimentary rocks have imprints of an extinct animal on them. An example of this is that Mr. Mashenko found an arrowhead fossil from an ancient squid- like animal. Also, if the rocks are round, that could mean that they were formed by water. If a round rock is found in a dry patch of land, it could mean that there used to be a lake or river in that area. According to Mr. Mashenko, it is very hard to date igneous rocks, but it is easier to date sedimentary rocks, because they have fossils and many layers in them.
I researched stalactites and stalagmites. The words stalactite and stalactite come from the Greek word “stalassein,” which means “to drip.” You can find most stalactites and stalagmites in limestone caves. Stalactites and stalagmites are mostly made out of calcite, which is made up of CaCO3 or calcium and carbonate irons. Water drips through the rocks and pick up carbon dioxide and other minerals from the limestone. The equation for this process would be: H20 + CO2 + CaCO3 = Ca (HCO3)2. It takes a very long time for a stalactite to form, it can take a century for a stalactite to grow just one inch. Water drips from the end of a stalactite onto the ground, until it builds up a mound of calcite, and eventually turns into a stalactite. I used the link http://science.howstuffworks.com/environmental/earth/geology/stalactite-stalagmite1.htm.

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leon
5/2/2012 06:24:38 am


Glaciers “leave souvenirs” by freezing around rocks and getting in between the cracks of rocks. Whenever water freezes it expands and breaks the rock. Then, when the glacier melts, the rock and its minerals fall and roll to the ground. Glaciers are wicked heavy. So when they’ve been there as long as an Ice Age, it leaves a giant “footprint”. It’s like a when you press down on clay and it creates a ditch.
Mohs Hardness Scale is a scale based on how hard minerals are. It was devised by Friedrich Mohs. It goes like this.
Rating Description Mineral Example
1 Very Soft Easily crumbles. Can be scratched with a fingernail (2.2) Talc
2 Soft Can be scratched with a fingernail (2.2) Gypsum, Soapstone
3 Soft Can be scratched with a copper penny (3.5) Calcite
4 Semi-Hard Can be scratched with a common nail (5.2) Fluorite
5 Hard Can be scratched with a common nail (5.2). Apatite
6 Hard N. B. Mineral of hardness 6 or more will scratch glass. Feldspar
7 Very Hard Can be scratched with a concrete nail (7.5). Quartz
8 Very Hard Topaz
9 Extremely Hard Used in industrial tools for cutting, grinding & sanding. Corundum
10 The Hardest
This was probably made so people could know what to cut the minerals with.

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Delia
5/2/2012 06:25:40 am

I learned a lot about geology from Mr. Mashenko. I learned that rocks can tell many things about history because they can fossilize organisms. Sedimentary rock is usually were fossils are found. The bones of an animal lay on a layer of rock and then after years and years sediments cover it. That is how fossils are imprinted in rocks. Rocks can show many animals that lived and died at one time. Now days, scientists have found a way to date sedimentary rocks. For example, Mr. Masnenko has found a species of extinct squid. Thanks to the rocks, it is still here and we can figure out the species, the time period it lived in, and other characteristics. Sometimes you can find fish fossils on land. This tells us that long ago, that place was underwater. Rocks help us piece together the past and see what it actually looked like.
I chose to do the Mohs Hardness Scale for part B. The Mohs Hardness Scale was invented by a mineralogist from Germany named Fredrich Mohs in 1812. The hardness scale was later named after him. The scale goes from 1, a soft talc stone, to 10, a hard diamond. Although the scale is still in use today, it has a few odd things about it. For example, topaz, corundum, and diamond are next to each other on the scale, but when corundum is twice as hard as topaz, diamond is four times as hard as corundum. On the scale, if something is higher in hardness that means it can scratch anything below it. The Mohs Hardness Scale helps us learn how hard minerals and rocks are. (I used Ms. Scollins links as well as http://www.allabout gemstones.com/ Mohs_Hardness_Scale.html)

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andrew
5/2/2012 06:25:41 am

What rocks can tell us about the history of our earth? Well for example if you have a rock with a fossil in it you can see what animal it was and what time period it was from. Another way is the scientist can scan the rock to show how old the material inside the rock. All rocks are basically old because like the rocks in our town or neighborhood are made up of rocks made from glaciers that made it come down to our area. Another way is if their was a earth quake the scientists can identify when the earth quake or volcanic eruption happened.

Stalactite and stalagmite come from the Greek word stalassein which means to drip. Stalactite is formed from water dripping into the cave and mixing with carbon dioxide and making it solidify and hang down from a cave. Sometimes it only grows a inch a century. Know the stalagmites are formed from the water that falls down from the ceiling of the cave and hit the floor making the floor rise and kind of look like a stalactite except on the floor of the cave.

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Erin
5/2/2012 06:34:33 am

Rocks are very good thing to tell us about the earth history. Rocks are the reason that we have mountains and oceans. The earth is made by rocks. I do believe that rocks are the closed thing that will tell use about history before humans, other than dinosaurs. They could find rock from almost the being of the earth.

I do know that geologists mean the people that study the earth. What geologist does to draw conclusions about the past is the use the rocks and other things that they have, then analyzes it. Then they mix it in with the other geologists work to come to a big conclusion.

This would have happened in the ice age 12,000,000 years ago. Ice bergs leave souvenirs by going into a frost. In the frost it freezes rocks. When the ice age started to end, all of the rocks were left. That is how ice bergs left souvenirs.

What the Mohs Hardness Scale does is it compares the hardest of things. The hardest thing on the scale is minerals. What is it has Talc to Diamond from softest to hardest of the mineral.
I got this info from http://www.childrensmuseum.org/geomysteries/cube/mohs_scale_alt.html#a

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Leo R.
5/2/2012 06:41:26 am

Rocks are made from cooled off molten lava. Rocks have minerals, which each have one ingredient. Geologists study rocks to help them figure out facts about Earth. Rocks have depth, circumference and diameter that geologists study. Minerals can be like granite or even salt.

Stalagmites are sharp rocks and minerals that grow from the bottom up. Stalactites grow from the ceiling down. These are found in very deep caves. I have seen these at Luray Caverns in Virginia. We took a boat through the caverns and used a flashlight. There were bats there too.

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5/2/2012 06:50:31 am

Rocks can tell us about the earth by how old they are. For instance, it easier to tell how old a sedimentary rock is than a metamorphic or igneous rock. This is because a sedimentary rock has layer after layer built up within it so it is like a tree but with layers, not rings. Geologists draw conclusions about the past by looking at rocks and their carbon dating to see what might have happened to the rock and where they are from. For example, let us say that there was a lake but now it is a desert. Scientists can tell that there was a lake by looking at the rocks that were in there in the past.
Glaciers leave souvenirs [fossils and rocks] by picking up some fossils or rocks and preserving them as the glacier passes by. The glacier makes these souvenirs perfectly round and smooth. For example, Mr. Mashenko brought in some fossilized type of squid that had been preserved in a glacier and it was in perfect condition.
I researched stalagmites and stalactites and I learned quite a bit about them. A stalagmite is a rock that grows upwards. This occurs when a cave keeps dripping water in one place and the minerals start to grow upwards and form an upward growing rock. A stalactite is a rock that grows from a ceiling of a cave. This occurs when the water stays at the top of the cave, starts dripping downwards, and creates a downward growing formation.

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austin
5/2/2012 06:52:39 am

How Do Geologists draw conclusions about the past? Rocks can help draw conclusions from the past. One form of the three forms of rocks that help us is sedimentary form. Sedimentary rocks take a long time to form. This can tell us that it took thousands of years to form solid. It is made up of many layers that could have twigs, leaves etc. fossils also help us conclude. They can also help us include that a certain animal was found a long time ago.
What is Mohs hardness scale? Mhos hardness scale is a scale that can be used to find the hardness or the softness of a mineral. On the scale the higher the number the higher the mineral’s strength is and the lower the number is the mineral is softer. If a certain item can scratch a mineral, it is a lower number on the scale. This means that it is softer than something that cannot scratch a mineral. Like for instance your fingernail is a 2.5 on the scale. If it can scratch a mineral it is less than 2.5 on the scale.

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Vincent
5/2/2012 07:08:28 am

Rocks can tell us about the history of the Earth by telling us how old a rock is. It can also tell us if there was a lake or volcano present where the rock was found. Geologists draw conclusions about the past by studying rocks. They can gather information about what the earth was like long ago. By studying how the earth has changed geologist can better understand how the environment and the geography have changed. Glaciers have helped change and shape our geography. Glaciers are large sheets of ice that transport material as they move. They carve and reshape the earth beneath them. A glacier erodes the land surface and carries the broken rock and soil far from the original site creating new landforms. Long Island was made by glaciers.

Mohs Hardness Scale is a scale that was created in 1812 by Austrian mineralogist Fredrich Mohs. He got his idea from watching miners. The Mohs Hardness Scale ranks 10 minerals in the order of their hardness. The scale rates these minerals on a scale of one – ten. The rating of one is the softest and can be easily scratched. More durable and harder minerals such diamonds were given the rating of ten.

He tested each mineral to see if it could be scratched. He used various tools such as a fingernail, knife blade glass as well as steel files. Minerals that could be scratched by a fingernail were given the rating of very soft. Talc is a mineral that is very soft. Talc is often found in baby powder and is very soft. The scale proceeds from soft to very hard to the hardest rating of ten. Diamonds are the hardest minerals and can be used to cut all other minerals. The only thing that can scratch a diamond is another diamond. That is why a people will often say diamonds are forever. Diamonds are often used as a tool to cut other minerals.
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Meaghan
5/2/2012 07:28:55 am

Website: http://dsc.discovery.com/videos/assignment-discovery-shorts-stalactites-and-stalagmites.html

Glaciers leave souvenirs. They can leave souvenirs in many ways. One is actually the ice preserving the body. This one is actually pretty strait forward. Here's an example. You are a great big mammoth just before the ice age hits. You are very hot under your long, fur coat. You are so dirty bugs are starting to come and infest your skin. Your fur is getting heavier by the minute. Dragging your body down, while the sun burns its way through your skin. You then see what you have been traveling for. A watering hole. Big enough to fit you and your pack with a lot of extra room. You are so thirsty and dirty you just jump in. Un aware that a sea monster lurks beneath and then, SNAP! It drags you down, down, down. Until, black. You are dead. Once you are dead, the sea monster spots a more delicious pray, leaving you to sink to the bottom. The ice age then hits. The lake freezes, leaving your dead body preserved by the cold ice. Frozen in your death position. Flash forward to the twenty-first century. A mountain climber is the first to venture up to your death spot. And because of the cold preserving your meat, and the lack of animals to eat your fur and meat, there you are. Perfect. Almost the same as the day you died. Once the climber sees you and the fish beside you he is thankful to the ice to keep you. Preserved. His souvenir. Off to the Museum you go. Where others bask in the beauty of the preservation the ice has created.

I studied stalactites and stalagmites. Some facts I learned where pretty interesting like, the stalactites and stalagmites are created by lime stone and water. Stalactites hang where water drips, leaving calcium behind. Stalagmites form where these water drops fall. Some similarities consist of what they're made of, their shape (they're shaped like a shark tooth), and color. The only differences are that stalactites hang from the ceiling, and stalagmites are on the floor. Stalagmites are also the result of the droppings of stalactites, whereas stalactites are the result of underground streams or a body of water.

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gilly
5/2/2012 07:34:36 am

How do rocks tell us about the history of the earth? Is the question that I have chosen to write about. The way rocks can tell us about our history is they can contain fossils. For example you can find a fossil of an animal in a sedimentary rock or a metamorphic rock. This can tell you about past types of animals like the belomite that died out 40 million years ago.
I chose the Mohs hardness scale. Mohs hardness scale is used to compare the hardness of minerals. The higher numbers on the scale are for hard minerals. For example topaz is a eight on the Mohs scale. The website that I used is childrensmuseum.org

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Ethan
5/2/2012 07:41:48 am

Rooks and minerals can tell us a lot about the history of the earth. For example, by examining and extracting rooks and minerals from an area, a geologist thousands of miles away from there can tell what the place was like millions of years ago. The geologist could figure this out by knowing what type of rock it is along with how the rock was formed. All you need is a simple amount of logic to determine what the area was like. A good example is the gem called tanzanite which is only found in a remote area of South Africa. So, if a geologist finds tanzanite, then he knows that it was from that remote area.


Do you know the difference between a stalagmite and a stalactite? Well, by the time you are done reading this you will!
You see, a stalactite is a rock formation at the top of cave walls which is caused when dirty water continues to gather at one place on a rock. The water deposits the sediment onto the rock causing it to get bigger over thousands of years. A stalagmite is made when dirty water drips from the top of a cave onto the bottom causing a large release of sediment to form.

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Maia
5/2/2012 07:53:37 am

Rocks can tell us many things about the earth. They can help us discover how long the earth has been around, and what the inside of the earth has in it. Some rocks and minerals grow like trees, which means they have the lines on the inside indicating how old they are. You can also use rocks to look at what could have come from the layers of the earth. Geologists can draw conclusions about our past by looking at these rocks, and also looking at certain rocks with fossils.  They can examine rocks that might have been used as tools, and can look at rocks that were tools. Glaciers leave souvenirs by showing the imprints of old fish. You can see their fossil in the glacier, which is pretty amazing when you think about it. I mean, who thought a glacier could have fossils in it?
There are some very hard minerals ( diamonds) and some so soft, they would crumble if you held one(talc). But how can you tell? By using the MOHS scale, you can see examples of each number on the scale. The numbers go 1-10, 1being like talc, and 10 being like a diamond. A human fingernail can scratch a mineral softer than 2.5, since a human fingernail is a 2.5 on the scale. That means I could scratch talc and gypsum! As for anything higher than that, we cannot scratch. Anything higher than a 6 can scratch glass! That means that stuff like quartz and topaz can scratch glass. It's pretty amazing how tough some of these minerals are!

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Sophia
5/2/2012 08:05:28 am

What can rocks tell us about the history of Earth?

Rocks tell us a lot about Earth and its history. One thing is that sedimentary rocks contain bones and fossils and such. The fossils I n these rocks tell us about the creatures that lived here before us. Also sedimentary rocks have layers and layers of different sediments that were cemented throughout the years. Each layer is a different time period. For instance on layer might be around 300 years ago while another might be around 1000 years ago. A rock from 300 years ago can tell what happened to the land. The rock could have been igneous and that tells us that a volcano erupted near that place.


Stalagmites and stalactite

The words stalagmite and stalactite come from the Greek word “stalassein” which means “to drip.” Both stalagmite and stalactite form because of dripping water. For a stalactite the water drips off of the ceiling. The water is not fresh anymore. On the way down to the cave the water picks up calcium carbonate, CaCO3. When CaCO3 is mixed with water it makes a new chemical called Ca (HCO3). As the water continues to drip the stalactite begins to form. For a stalagmite the water drips off of the stalactite and onto the ground. As the water continues to drip the stalagmite grows.

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Lara B
5/2/2012 08:14:17 am

Rocks tell the story of the history of the earth. Rocks have been around for centuries. They may not look the same as they looked long ago because they have been chipped at, pressed and probably been through lots of storms, but they are still the same rocks. Rocks can tell us what went on, on earth when humans weren’t alive. Rocks can tell us if the town we are in right now, Croton, was under water, frozen, hot, or warm a long time ago. Maybe if there are igneous rocks, there may have been a volcano. Rocks could hold fossils of plants or bones. We could find out clues about the appearance of animals and plant life.

Geologists use the Mohs hardness scale to compare the hardness of a mineral. The higher the number on the scale, the harder the rock. The hardness of a mineral can also help geologists identify a mineral.
Any mineral can scratch only another mineral that is lower than it on the scale. A diamond with a number ten, can scratch a mineral with a number smaller than ten. Therefore a diamond could scratch almost any mineral. Another mineral, calcite can’t scratch any above a four.

As you can see, rocks and minerals are important to humans.

I researched minerals at this site: http://www.childrensmuseum.org/geomysteries/cube/b2.html

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Cassidy
5/2/2012 08:58:18 am

Part A:
How do geologists draw conclusions about the past?

Geologists draw conclusions from the past by studying the Earth. They also study rocks and minerals. You can tell a lot from the past by studying rocks. You can see how old the rocks are, what type of rock it is, and you can figure out where it came from. For example, if you find a 10,000 year old Igneous rock, you can see which volcano it came from, and when it erupted.

Part B:
Mohs Hardness Scale

Mohs Hardness Scale was devised by Friedrich Mohs the German mineralogist in 1822 to measure the relative hardness or scratch resistance of various minerals. He based it on ten readily available minerals. As it is an ordinal scale, you have to compare two minerals to decide which is harder. The scale is neither linear nor logarithmic. For example, corundum is twice as hard as topaz, but diamond is almost four times as hard as corundum. The hardest rock is the diamond. The least hardest is the rock Talc. Each mineral can scratch only those minerals below it on the scale. You can scratch a rock with a fingernail, (2.2) copper penny, (3.5) pocket knife,(5.2) piece of glass, (5.5) steel file or concrete nail (7.5)
piece of corundum. (9)

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maddie
5/2/2012 09:15:07 am

The rocks today can tell us about the past. One way they can do this is the shape. The shape of the rock can tell so many things. It can tell if it's an igneous, metamorphic, or sedimentary rock, or if it was in an ice glacier or was washed up on the shore of a beach. After the geologists look at these rocks to see their past, they draw conclusions. How they draw conclusions is they look at the qualities of the rock. The qualities would be things like if it was an igneous rock it would be formed from when magma cools. Or it could be something like a rock that 's made up of pushed together layers. Any of these qualities would help a geologist draw a conclusion. Speaking of qualities, these qualities have to come from somewhere. One way this happens is glaciers. Sometimes glaciers can leave rocks behind. What happens is after the ice age, which happened thousands of years ago, rocks got stuck inside of glaciers. Before the glaciers had the chance to melt, the rocks inside of them got shaped and pressed against from the ice. So when the glaciers finally melted, the rocks turned out to be either fossilized or smoothed down. That is the souvenir that icebergs leave behind.
The subject that I researched was the Mohs list. It showed the minerals in hardness order. Of course the most hardest one was the diamond. But the one that really interested me was the second hardest one, the corundum. This mineral comes in many different colors. A more common name for the blue or red version of it is sapphire and ruby. I think it's really cool how the ruby and the sapphire's real name is corundum. It's really weird to think that all this time we've been calling it two different names.
The actual Mohs list is: 1- Talc, 2- Gypsum, 3- Calcite, 4- Fluorite, 5- Apatite, 6- Orthoclase, 7- Quarts, 8- Topaz, 9- Corundum, 10- Diamond. My favorite is topaz. I think the color of it is really beautiful. It reminds me of summer and a little bit of spring. The color is really unique and happy. That's why it's my favorite. People usually say that the diamond is the prettiest, but I think it looks like any other crystal that you can find in the sand. My second favorite is the Fluorite. I think it's pretty because of the interesting details of it. Not only is it a rock, but on the rock are little gems. Fluorite is so soft that people can't even make jewelery out of it. That's okay though, I think it's better not as a necklace or a ring.


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Vishwanka
5/2/2012 09:34:56 am

What can rocks tell us about the history of the Earth?
Rocks tell us a lot about Earth's history. There are three main kinds of rocks. Igneous, sedimentary and metamorphic rocks each tell us about the Earth. The layers in a sedimentary rock can tell us how old the rock is or how many layers it has gone through. For example, sandstone is a sedimentary rock. Sandstone has many different layers and each layer has a different color. Sedimentary rocks are also made up of the fragments of other previously exsiting rocks. Igneous rocks can tell us a lot about the Earth too. Igneous rocks are formed when a volcano erupts and lava cools. When the lava cools, it hardens and an igneous rock is formed. The rocks are classified according to their compostion and texture. Igneous rocks help us learn about our planet by possibly telling us when the volcano erupted and other information. Metamorphic rocks are important too. These rocks are formed by pressure from heat and chemical reactions that cause them to change. These rocks can tell us how much pressure the rock has taken. This is how rocks can tell us a lot about Earth's history.

Stalactites and Stalagmites....
Limestone caves, where most stalactites and stalagmites are found, are mainly composed of calcite, a common mineral found in sedimentary rocks. Stalactites have to hold on to the cave. Stalagmites grow from the ground. Stalactites are formed when rainwater falls over a cave and trickles through rocks, it picks up carbon dioxide and minerals from limestone. The water carries the substance, basically dissolved calcite, through the cracks of the roof of a cave. Once water comes into contact with the air inside the cave, some of the calcium bicarbonate is transformed back into calcium carbonate, and calcite starts to form around the crack. Stalagmites are formed when the water dripping from the end of a stalactite falls to the floor of a cave and deposits more calcite into a mound. This is how stalactites and stalagmites are formed.

website: http://science.howstuffworks.com/environmental/earth/geology/stalactite-stalagmite1.htm

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max
5/2/2012 09:36:50 am

Glaciers do leave “souvenirs” behind. When glaciers shift they take up rocks, minerals, skeletons, and plants that get moved around. Some fossils from Asia are found in North America. This is because of glaciers. When glaciers shift and move they also deposit rocks, minerals, and fossilized plants.

Stalagmites and stalactites come from the Greek word, stalassein. Stalassein means drip. This explains what stalactites and mites are named after. Considering that stalactites and mites are formed by dripping and dropping water.

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Sierra Flores ;P
5/2/2012 10:13:12 am

Some of the oldest rocks ever found have been estimated to be about 3.9 billion years old. It is likely that these rocks were present when Earth was first formed. Geologists can usually draw conclusions from the rock themselves, when a rock has a bunch of cracks or looks kind of demented it most likely a metamorphic rock. If the rock is able to break into equal pieces them it’s most likely a sedimentary rock, if the rock was formed by magma it’s probably and igneous rock. Glaciers can leave souvenirs. They do this because their heavy weight and mass are so big that they actually can cause the land beneath to reform. The ice erodes the land and carries broken rocks far from their original places, which results in new unique glacial landscapes.
The Mohs Hardness Scale is a method that geologists use to figure out how hard a rock or mineral can really be. I learned from the website www.children’smuseum.org/ that your fingernail is exactly a 2.5 on the hardness scale so if you can scratch a rock with your finger nail it is less than or is a 2.5 on the hardness scale. A pocket knife is a 5.5 on the hardness scale so if a rock (or mineral) can be scratched by a pocket knife it is or is less than a 5.5 on the hardness scale.

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Darren
5/2/2012 10:15:34 am

Rocks can tell us many thing about the earths past in plenty different ways. One way is fossils and what kind of creatures lived in the before time. Fossils contained many different small creatures from insects to snails. Another way of telling about the history of the earth is volcanoes and what was produced from them and what the mixed with. There are many ways to figure out the history of the earth but these were just two.

1 Very Soft Easily crumbles and can be scratched with a finger nail
2 Soft Can be scratched with a fingernail
3 Soft Can be scratched with a copper penny
4 Semi-Hard scratched with a common nail
5 Hard scratched with a common nail
6 Hard hardness 6 or more will scratch glass.
7 Very Hard scratched with a concrete nail
8 Very Hard
9 Extremely Hard Used in industrial tools for cutting, grinding & sanding.
10 The Hardest Diamond is used to cut all minerals including diamonds.

Diamond is super hard to cut and requires tools and knowledge. That is the MOHS scale. I enjoyed the presentation in class today.

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damien
5/2/2012 10:29:52 am

Rocks can tell us that the rock is either sedimentary,igneous,or metamorphic.Geoligists draw conclusions by finding fossils and looking at the rocks and minerals and seeing their shape,size,color,and texture.Glaciers leave souveners by lets say an animal died in the ice age and froze it would leave fossils or if it was extremely greatly preserved the body will still be intact.
Stalagmites are rocks usually found in caves but are created by dripping water and are growing upwards.A Stalactite is also created by dripping water but they are usually found growing taller facing downwards.

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alexa (good1)
5/2/2012 10:46:09 am

Part A: what can rocks tell us about the history of the earth?
During the time of the ice age, the ice would form round rocks .but since the Ice age was a REALLY long time ago, rocks may not look so round since they go through changes that might include metamorphic and sedimentary rocks. Since rocks go through changes like metamorphic and sedimentary, it’s easier to date igneous rocks because they don’t go through those changes like metamorphic and sedimentary rocks. They are formed with magma and their basic types of textures are glassy, fine grained, coarse grained, and porphyritic. Also you can find fossils all over the world from ancient times. Ancient fossils are so small that sometimes you have to use a microscope to look at them. Also in ancient times they would use flint and it was very sharp they used it a lot for cutting and weapons. Also all Stone Age tools were made out of stone. Stone age people would also you any things they found locally.
Part B: Stalagmite and stalactite
The words stalactite and stalagmite come from the Greek word "stalassein," which means "to drip." Stalactites and stalagmites grow because of water running over and through inorganic material. Limestone caves are where most stalactites and stalagmites are found, are mainly composed of calcite, a common mineral found in sedimentary rocks. When rainwater falls over the cave and trickles through rocks, it picks up carbon dioxide and minerals from limestone. Stalagmite and stalactites all are different sizes and different textures. You usually find stalactites and stalagmites in pairs, and sometimes they'll even grow together to form one big column.
Website :
http://science.howstuffworks.com/environmental/earth/geology/stalactite-stalagmite1.htm

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5/2/2012 10:49:41 am

Rocks can tell us a lot about the history of the Earth. Rocks can tell us a lot about the history of the Earth because rocks don’t just magically appear on the Earth, there has to be a process of thing that has to happen like in the rock cycle. The rock cycle is a cycle of how rocks are made. Rocks provide us with many different things that are very useful to humans and even animals, for example, flint is used as a fire starter and in the stone age cave men used it for weapons, marble and granite are often in kitchens or around the house, a mineral called Sulfur is used in matches, fireworks and even gun powder. Rocks are helpful to us humans and tell a lot about Earth.

Stalagmites and stalactites are very interesting, they are almost like icicles! Stalagmites and stalactites are solid rocks that are formed when water that has minerals in them is constantly being dripped on the rock formation. Stalagmites and stalactites are hard to find on the surface but in caves, they are very common, so if you ever want to see one in person you better have good training!

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AVA
5/2/2012 11:12:05 am

The history of the earth could be found in a small rock. Depending on what type of rock it is you can find a piece of history. A sedimentary rock, since it’s made out of layers such as; mud, sand, pebbles, bones, leaves and shells may contain items from the past. There have been some rock forms that contain fossils from animals like Mammoths or a cyber tooth tiger. Not only fossils are found in rocks but crystals found in igneous rocks.
To help determine the type of rock it is with Moh’s hardness scale. A hardness scale is 1-10, 10 being the hardest and 1 being the softest. For example 1can be a talc rock (chalk) and a 10 would be diamond. A hardness scale is often used by geologists. Apitite, a 5 on the hardness scale is as hard as a pocket knife.

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Meagan
5/2/2012 11:13:25 am

Rocks can tell us about Earths past. They tell us by the fact that we can figure out how they were formed telling us roughly how long they’ve been around. Also they tell us about types of rocks they have been before they were the kind they were at that time. They also tell us what the Earth is made of. That can give us a rough estimate of about how long some parts of earth have been around. Geologists come to conclusions about the past by Figuring out how these rocks have been made and what has changed them, that tells them a few things that might have been going on at that time. Glaciers leave behind souvenirs. One way they leave/left souvenirs is that as they move they pick up rocks, the rocks freeze and change into different rocks. Also glaciers left behind lakes and rivers.
I’m doing the Mohs hardness scale. The Mohs hardness scale was developed in 1812, by German mineralogist Friedrich Moh. Friedrich Moh lived from 1773 to 1839. The scale grades the minerals from softest (1) to the hardness (10). An example for 1, is Talc, an example for 2 Gypsum, an example for 3 is Calcite, an example for 4 is Fluorite, an example for 5 is Apatite, an example for6 is Orthoclase, an example for 7 is Quartz, an example for 8 is Topaz, an example for 9 is Corundum, and an example for 10 is Diamond. Each mineral on the scale can be scratched by something of the same or higher level, nothing lower. One last example is your fingernail ranks a 2.2-2.5, so it can scratch any thing 2.1 and lower, nothing higher.
Sources:
http://www.amfed.org/t_mohs.htm
http://www.rockroost.com/Mohs-hardness-scale-tips.shtml
http://library.thinkquest.org/J002289/mohs.html
http://chemistry.about.com/od/geochemistry/a/mohsscale.htm
http://www.rocksforkids.com/RFK/identification.html

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Katie
5/2/2012 11:19:17 am

Today in class we learned all about geology, which is the study of earth. What can rocks tell us about the history of the earth? When a rock forms either from sediment or magma (lava) cooling, living things such as plants or insects can get trapped in the rock. When geologists cut through that rock, they can tell how things lived and when. The texture and composition of rocks can also teach us what they were made from. For example, different minerals make different rocks and rocks created from volcanoes contain magma and are called igneous. There are three types of rocks – igneous, metamorphic and sedimentary. Igneous rocks are the oldest and can tell us a lot about volcanoes and where they existed on earth.

You can use the Mohs Hardness Scale to compare the hardness of any mineral. The higher the number on the scale, the harder the mineral is. The Mohs Hardness Scale consists of 10 classifications - 1 being the softest and 10 being the hardest. The diamond is the hardest natural mineral so it is a 10. A way to use the scale is to scratch a rock with your fingernail and if you can make a mark on it, it is a 1.

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Meredith
5/2/2012 11:20:29 am

Part A

What can rocks tell us about the history of the Earth?

There are lots of rocks in the world. Some smooth, some shiny, some small, some big. Out of all the rocks in the world, there are three main types. Those types of rocks are called Igneous, Metamorphic and Sedimentary. These rocks can tell us about the history of the world because of fossilized animals and plants. When these animals get fossilized it helps us see what kind of animals and plants used to live on the earth and how long ago they were alive.

How do geologists draw conclusions about the past?

Geologists draw conclusions about the past in 2 ways. One is they look at the different types of rocks and see what has happened to them. If there smooth or if there rough. By feeling the texture, looking at the color of the rock and seeing the size this can help them see when the rock was formed. Also, fossils help geologists draw conclusions about things like dinosaurs, mammoths and cave men. If a fossil is found that has a dinosaurs bone they know that a certain kind of dinosaur live here or if the bones of a mammoth are found somewhere they know that the maybe lived there too.

How do glaciers leave souvenirs?

Thousand and thousands of years ago the glaciers of the Wisconsin Ice Age made 5 beautiful fresh water seas called; Lake Superior, Lake Huron, Lake Michigan, Lake Erie and Lake Ontario. These lakes stretch thousands and thousands of miles through the U.S. and Canada. These lakes also contain an estimate of 35,00 islands!!! (http://seagrant.wisc.edu/glaciers/) Another gift from glaciers is that a glacier can pick up a very rare rock or a rock that’s usually only in a certain state and bring it to another. This is a very cool souvenir! Imagine going down to the water and finding a very rare and pretty rock I would love that, as I love rocks!


Part B


What’s Stalagmite and Stalactite? Stalagmite and Stalactite are types of rocks that look amazing, that are HUGE (can be as big as the grand central station) and as a website stated, they look “life-like and kind of creepy”. They are formed because of water running over and into inorganic material. The running water makes them different sizes and different shapes and it gives them different marks and holes inside the rocks and on the surface of the rocks. These two types of rocks are usually found in limestone caves. The main mineral the cave is made out of is called calcite. Calcite molecules are made out of calcium and carbonate ions. When it rains outside and the rainwater falls into the caves surface, it moves through the rocks picking up carbon dioxide and minerals from the limestone. All of these gets turned into this equation: H20 + CO2 + CaCO3 = Ca (HCO3)2. Ca (HCO03) is called calcium bicarbonate. That water is full of the substance; H20 + CO2 + CaCO3 = Ca (HCO3)2, this carries through the cracks of the roof and the ceiling of the cave. Some of the calcium bicarbonate turns back into calcite and this starts to form around the cracks in the cave. As more and more water drips the thickness and the length of the calcite becomes bigger and the thickness wider and eventually stalactite forms of the ceiling. The water that drops from the stalactite rocks drops to the cave floor, this is where stalagmites comes in. This deposits more calcium into a mound on the ground of the cave and this forms the stalagmite rock. The shape of the rocks are cone like. These rocks are in caves all over the world and they take centuries to form.

Reply
Leo $
5/2/2012 11:22:11 am

I will be answering the question how do glaciers leave souvenirs? Glaciers leave rocks and even some times lakes as souvenirs. The glaciers cut scars in the earth that later on filled up with water. Glaciers also can carry rock and then they leave them behind or when it melts it leaves them wherever it melts. These rocks are carried from one place to another by the glaciers and it helps geologists under stand the patterns of the glaciers and where some rocks are most commonly found.
I am going to write about stalagmites and stalactites. A stalactite hangs from the ceiling of a cave and is ussually met by a stalagmite. A stalagmite come upward from the rock and sometimes meets the stactite to form a collom. A stalagmite is formed by watter dripping from the ceiling and leaving a deposit that builds and builds over many many years. A stalagtite is formed by when the water is dripping dow it leaves a deposit on the top and the bottom.

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Hannah G
5/2/2012 11:26:48 am

Rocks can tell us a lot about the history of the Earth. There are 3 main types of rocks. Those types are Sedimentary, Igneous and Metamorphic. Igneous rocks are rocks formed when magma cools. An Igneous rock can tell us a lot about history. One way is that it can date back to when the volcano erupted. If there was an ancient volcano that isn’t there anymore, it would tell us a lot about it. Metamorphic rocks are rocks that has been changed by pressure, heat or both. Metamorphic rocks tell us about history of the Earth. One way a Metamorphic rock can tell us a lot about the history of the Earth is that when they have pressure heat applied to them they could break apart causing the middle of the rock to be exposed. When the middle of the rock is exposed it has rings that represent a certain amount of years like a tree. When you see these rings you can count them (it is gonna be a while!). With a metamorphic rock, you can feel the edges of it to see if it has smoothened because of the see or other things. A Sedimentary rock can tell us a lot about the history of the Earth. A Sedimentary rocks are rocks that are formed when layers of rock are cemented together. One way a Sedimentary rocks tells us a lot about the Earth is that they can include shells bones and other things. If a rocks has fossils in it, it can tell us about an animal that has been extinct for many MANY years. The fossil may be as old as 10 million years old. When you find a fossil, it tells you a lot about what happened back 10 million years ago.

Minerals can either be very hard or very soft. On a scale of one to ten chalk would be the softest an diamonds would be the hardest. This scale is called the Mohs scale. If you can scratch the minerals then you can tell it isn’t that hard on the Mohs scale. All minerals can scratch minerals with a lower hardness scale then theres. If i were to take 2 rock an rub them together I would have a white line on one of the rocks ( the softer one) it would look like chalk.

Sources: My notes
http://www.rocksforkids.com/RFK/identification.html
http://www.childrensmuseum.org/geomysteries/cube/b2.html

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jacob
5/2/2012 11:41:52 am

What can rocks tell us about the history of the Earth? The way rocks can tell us about the history of the world is by layers (sediment), temperature and size (igneous) and by how compressed or how deep it is (metamorphic). If hypothetically a metamorphic rock is 10-25 km’s deep it must have been formed centuries ago by an igneous and a sedimentary rock.

The MOHS (named after German mineralogist Frederich Mohs scale measures the hardness of all objects (mainly rocks and minerals). If you were to scratch something with your fingernail, which is a 2.5/10 on the MOHS scale, in order for it to make a mark, the object would have to be a 2.4 or lower on the MOHS scale. A diamond, on the other hand, is a 10 on the MOHS scale, which makes it virtually impossible to mark, and can cut or scratch any material.

Reply
Taylor C.
5/2/2012 11:48:07 am

How do glaciers deposit rocks?

As a glacier forms it picks up rocks. Say a rock is picked up in Canada. It is then slowly, over tens of thousands of years, that rock is dragged by the glacier and is deposited in to a riverbed when it melts. This is how glaciers deposit rocks.

What is the Mohs scale?

The Mohs Scale is a scale devised by a German Chemist, Freideric Mohs. This scale measures scratch-ability. This scale ranges from the scale of 1 (talc) to 10 (diamond). When a certain rock or mineral scratches another one, that mineral goes higher on the scale. The Mohs scale is a very unique way of determining hardness and scratch-ability that is a prime way of measurement today.

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chris
5/2/2012 12:01:41 pm

• Glaciers leave souvenirs when they pick up rocks and drop them back off at a different location. They do this when they cut though the ground and make a river or valley. They trap the rocks that were originally on the ground and then take the rocks to a different location. Then the rocks that were taken and dropped off are called souvenirs.

The hardness scale goes from 1-10. 1 being weak, 10 being hardest. 1 is something you can break off with your fingernail. 10 is the hardest of the hard. It is called diamond. The first 3 are easy to break, number 4 is semi hard so not to easy and not to hard. 5 and 6 are hard, 7 and 8 are really hard, 9 is extremely hard and 10 is the hardest.

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Maccray R.
5/2/2012 12:01:49 pm

I think that rocks can help geologists tell the past because there are ways to study the rock to see where it came from and how it got to where it is now. For example if sandstone had some of its side chipped away you could infer it was in the water or part of a glacier. Another way geologists are able to understand the past is to dig a foot or two under the surface and find rocks. This may mean that maybe some time ago the ground was a little bit lower. Finally I think that rocks are a big help to geologists when they want to know about the history of a certain area. For instance with igneous rock, the geologist could infer that there is a volcano nearby. Studying them can teach us about the history of the Earth.
I decided to research the Mohs scale and used this website http://www.childrensmuseum.org/geomysteries/cube/b2.html and http://www.gemselect.com/gem-info/gem-hardness-info.php. Friedrich Mohs, a German meteorologist, created the Mohs scale in 1822; it was created to measure the hardness or scratch resistance of minerals. I learned that the scale goes from 1 to 10, 1 being the softest and most crumbly. For example Talc is the softest rock and is rated a 1. An example of a 10 on the scale would be diamond. It is the hardest rock and nothing but another diamond can scratch it. The Mohs scale can help geologists understand different types of rock by scratching it, if it is rough it can be decided that it is a 6 or a 7. If you take a rock that is a 7 on the scale, such as quartz, and scratch an 8 rock, such as topaz, the topaz would not scratch. But if you use the quartz to scratch another 7 it will scratch the other rock, it will also scratch the other rock if it has a lower grade.

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Emily
5/2/2012 12:12:12 pm

Rocks are able to make fossils. These fossils show us what animals lived millions of years ago. When we study how rocks form and change we get a better understanding of the rocks and the history of our earth. In the study of geology there are 3 categories of rocks igneous, metamorphic and sedimentary. Rocks also showed us the several ice ages that happened years ago. The oldest ice age occurred around 120,000 years ago. Many rocks were left by the ancient ice ages. Glaciers went from regions to regions scarring the bedrock and creating lakes. We all know this thanks to rocks. Most fossils found are left from animals.

Stalagmites formation appears under an evident pH conditions within the underground cave. Stalagmites should usually not be touched skin oils can change the surface where the water clings then affecting the growth of the formation. Stalagmites can also form on concrete ceilings and floors, although they from stauncher and earlier in a natural cavern. They occur in limestone caves and they grow in pairs the water dissolves some of the limestone, carrying it downward if it grows on a ceiling.

Geologist can tell by seeing and feeling the texture, form, shape, size and the color. They can analyze it and make educated guesses on how the rock could turn out in which divided category you would place it in.

Reply
Ellie
5/2/2012 12:30:29 pm

Today, Mr.Mashenko came in to do a presentation on geology. Here are some of the things we learned. Rocks can tell us plenty about the history of the earth. For one thing, by dating rocks we can find out the time of a volcanoes eruption or an island or mountain's creation. Also, fossils of animals that used to live on our planet can be found in sedimentary rocks. Geologists can draw conclusion about the past by find what type, and dating rocks than applying that information to conclude about super continents, and landforms.
During the ice age, there were glaciers in the hudson valley. Glaciers leave behind souvenirs when they melt. Glaciers carve through the ground and make rivers, valleys, and fjords. Glaciers can scratch rocks too, which can help scientists find that the glacier came through.
I did some research about stalagmites and stalactites. They're created by mineral rich water dripping from the ceilings of caves, then leaving the minerals behind, which creates stalagmite and stalactites. To remember which is which, the trick is that stalactites have a c in the name and they protrude from the ceiling, which starts with a c, stalagmites have a g in them and they protrude from the ground which starts with a g. It takes thousands of years for these structures to form. Limestone caves are where stalagmite and stalactites are most often found. When they are formed in limestone caves, they are mostly made up of calcite, or calcium bicarbonate.

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Yesenia M
5/2/2012 08:58:35 pm

Rocks can show the history of the earth by what you see in it, One example of this is a rock with a crack in it. The crack’s are researched to determine or get an idea from the past, present and a possible future. This normally happens by the pressure of the earthquake expanding the rock leaving a trace of history regarding the time period and the evidence of what could have occurred. Another kind is a sedimentary rock. That rock has a lot of layers that shows the earths past. The rock demonstrates the different layers within that type of rock only. No other rock has been known to show the same characteristics.
I decided to research stalactite and stalagmites. Here are a few of my notes about them. Stalactite is made from disposition calcium carbonate and other minerals. Every stalactite begins with a single mineral-laden drop of water. A stalagmite is a type of spelethen that rises from the floor of a limestone cave. This stalagmite formation occurs only under certain pH conditions within the underground cavern. Stalactites and stalagmites can also form on concrete ceilings and floors, although they form much more rapidly there than in the natural cave environment. The resource that I used was wikipidia.com

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Charlotte
5/2/2012 09:20:12 pm

What can rocks tell us about the history of the earth?  Rocks can tell us many things about the history of the earth including which animals lived thousands of years ago.  A fossil of a dinosaur could be lying around thousands of years ago and eventually could have formed into a rock.  Eventually scientists will wind the rock and they can analyze how that animal got there, and where it is from.  Another way rocks can help us tell how old the earth is, is by looking and analyzing sedimentary rocks.  Sedimentary rocks have layers and layers of different aged rocks, so if you looked at or almost tried to break apart the rock, you could tell what the earth was like along time ago.  



 Stalagmites come from the ground, and stalactites come from the ceiling.  Stalagmites and stalactites come from the cave ceiling dripping and dripping.  They don't form in just a few minutes, it takes a very long time to get how tall they are or may get.  In some stalagmites pearls can even form!  How it happens is that water keeps on dripping and eventually forms a little basin full of water and a little pearl forms.  Stalagmites are very interesting!

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Riley <3
5/3/2012 06:37:55 am

Rocks can tell us a lot about the history of the Earth. Sometimes geologists find fossils in rocks. Fossils can tell us a lot about the history of the Earth. They can tell us what kind of animals used to live on Earth. Geologists can also date rocks. By doing that they can find out what types of rocks were on the earth at what times.
Mohs hardness scale was a scale of how hard different minerals are. It also says what they are in are used for. The hardest mineral is the Diamond. The least hard is talc. Which is used in talcum powder.
The website I used was www.amfed.org

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Matt Harris :/
5/3/2012 09:46:43 am

* What can rocks tell us about the history of the Earth?
Rocks can tell us about the history of earth because they have been around for so long. Some rocks have been aroung for over 20,000 years. Also by looking and feeling the rocks you could tell the diffrent things it has gone threw. If it came from lava burning or layers of moving crust. Some rocks have a diffrent kind of feeling than others.
How do geologists draw conclusions about the past?
Geologists draw conclusions from the past by studying the Earth. They also study rocks and minerals. You can tell a lot from the past by studying rocks.

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