Rocks and Soils - Order In the Rocks
You know that rocks are made of minerals. Now it is time to find differences between various rocks.
You will learn about the three basic rock types. Then you can use that information to group rocks into these three types.Igneous rocks
It's Hot, Hot, Hot!
Do you might think that many summer days get a bit hot? Do you sweat as the thermometer creeps up to 38° Celsius (about 100° Fahrenheit.) These temperatures are nothing, compared to the heat within Earth. At depths of 60 to 200 Kilometers (36 to 120 miles) below the Earth's surface, temperatures reach over 1400° Celsius (over 2500° Fahrenheit) this temperature melts rocks. This is also where we will begin Rocky's (the rock) incredible journey.
Rocky was hanging out deep within Earth when he quickly began his journey upward. He traveled through a lava tube and blasted up out of a volcano. As he went through the air he began to harden. You know the saying, “What goes up must come down.” When he hit the ground he continued to cool and harden.
As soon as Rocky hit Earth, he began to move quickly down the mountain. "Wow, what a ride!" Not only was he part of a great river of red hot lava meandering through the tropical mountainside, he was also feeling a little chilled. He was cooling down. Little did he know that within a few short minutes he would get the "big chill." Rocky was heading towards the ocean. When Rocky met the great salty sea, he really cooled down. Before he could say "How cool," Rocky became a rock.
Taking it for "Granite"
You can make your own granite (igneous rock) by following the recipe below.
- One tablespoon of pink aquarium gravel
- One teaspoon of white aquarium gravel
- One-half teaspoon of black or any dark colored gravel
- White glue
- Paper cup
- Craft stick or a plastic spoon
- Mix gravel in a paper cup.
- Add the glue and mix well with the craft stick or spoon.
- Allow the mixture to dry for 24 hours.
- Compare your sample of granite to a sample of the real thing. How are they alike? How are they different?
Rocky and the Rockies
As millions of years passed, Rocky found himself being pushed higher and higher above the valley floor. Rocky was becoming part of the great Rockies. He liked the view from his home on the mountain side. It seemed he could see forever. But nothing lasts forever, not even a rock. One day after a raging downpour, Rocky lost his grip on the mountain side. He started tumbling down the mountain until he found himself in a stream of rushing water. Rocky's journey down the mountain creek was stop and go. Sometimes during the spring runoff, the stream rushed down the mountain carrying Rocky a long way. Other times Rocky remained stayed put for a long, long time.
The Big Splash!
One day a swift current threw Rocky on the banks of the stream. He looked at himself. He had changed. Rocky was a round mound of rock. Colliding with the other rocks in the stream had caused him to lose his "rough" edges. The stream eventually took Rocky to a river. During his journey down the mountain, Rocky found himself getting smaller and smaller.
Parts are Parts!
Now you may think that Rocky has "come full circle" in the great rock cycle, but he is not finished with his adventures yet. Rocky had become a tiny pebble. He had been worn away to almost nothing by the forces of nature on the Earth's surface. Parts of Rocky were scattered all about. As our tiny friend (and his parts) lay about on the salty ocean floor, he soon lost his view of the life that flourished around him. Rocky was once again being buried. Sediments from the river that brought him to the great sea and the remains of past ocean life soon covered Rocky.
The pressure of the sediments above him had cemented him together. He looked nothing like his old self, but was a "new kid on the rock." Eventually the mountain building processes had brought him to Earth's surface.
You're The Scientist!
This experiment will help you to understand more about sedimentary rocks and the processes that make them.
- One cup of sand or soil
- One half cup of small rocks or gravel
- Paper cups
- Several small sticks
- Other small objects you may want to add
- White glue
- Place the materials in a paper cup. Put hand over cup and shake.
- Mix glue with water about half and half. Pour into cup. Place the cup in a place where it will not be disturbed.
- The next day peel the paper cup off.
- Observe the sediments and draw a diagram representing the sediments in your cup.
- If the sediments were cemented together, what type of rock would you have?
Slowly - over time
The story of Rocky is a very "time consuming" one. Millions of years passed. Rocky was buried beneath tons and tons of rock material. The pressure from the rock above him was great. Eventually, Rocky started to warm up again. Over many millions of years, Rocky found himself changing again.
You have probably heard the word "morph" before. There is a very popular book and television series called "Animorphs©." These books and shows are about people who morph into animals. Do you know what "morph" means? Think about your answer and then highlight the box below.
Answer: The word "Morph" is part of the word Metamosphosis which means "to change."
Metamorphic rocks are formed under extreme pressure and heat. These conditions are not great enough to make the rock melt again, but the heat and pressure do cause the minerals within the deeply buried rock to change. Sometimes the minerals will become rearranged. This can cause the rock to become layered. As the temperature continues to rise, the crystals within the rock may grow in size. Chemical changes may also take place at even higher temperatures.
- Pancake/Waffle mix that needs only water
- One bag M & M® candy
- Large mixing bowl
- Waffle maker
- Measuring cups
- Vegetable Oil or Cooking Oil
Follow the steps below to make your own tasty rocks. (Make sure you have and adult to help you)
- Heat and oil your waffle maker. This represents the heat and pressure from the earth.
- Mix up the batter.
- Pour in the M & M’s® candy and mix well. This represents sediments or magma. You could add any other types of sediments you think would taste good such as coconut, walnuts, chocolate chips etc.
- Place the batter on the griddle. Make waffles.
- Notice how the heat and pressure changed your rock. Sedimentary to metamorphic through heat and pressure.
Read each question carefully. Then look at the photographs below the question. Click on the photograph of the answer you think is correct.
Which of the following rocks looks like it is igneous?
Which of the following rocks looks like it is metamorphic?