Changing Earth's Surface - Unstable
Have you been aching for some ocean front property? Just sit tight for several million years. You might get it. As you know, the earth is continually changing. The outer layer of the earth is called the crust. Under the continents, the crust is over 30 miles thick. Under the oceans, the crust is only about seven miles thick. The crust is broken into chunks known as plates. The plates move about on a fluid layer of the earth. Plates can move apart, come together, and push past each other. When they do, tremendous things happen.The Mighty Himalayas
This spectacular mountain range is the result of plates colliding. The 30-50 million years ago the continental plate that India is on came crashing into the Eurasian plate. The crust pushed up forming the some of the tallest mountains in the world. Mount Everest, in the Himalayas is 29, 028 feet tall and still growing!
This pushing up of the land is called uplift. It is one method of mountain building. You will learn others.
This experiment requires a Snickers® candy bar. It works best with a small, fun-sized one, but you don't have to tell your folks that. This candy provides you with a great and tasty model of Earth's structure and its plates.
Carefully unwrap and take out your Snickers®.
Bite off one end of your candy bar! Look closely at the layers of the earth!
Gently push your finger into the surface of your candy bar. Make sure that you crack the chocolate layer.
The cracks your finger makes represent Earth's plates.
Now it's time to play with your candy bar! Gently pull it apart. Notice how the "plates" move on the caramel. Push it together. Try to build your own little Mount Everest!
This is a Snickers® model of uplift. One plate pushed into another buckling the bar.
Once you finish testing how the plates move, destroy your evidence!
Have you tried sliding a heavy box around? If you haven't, you are really missing out. What usually happens is you are sliding along just fine when you hit a little bump or ridge. You push harder and harder until you conquer the bump. The box surges forward, much faster than before.
The box story is a simple example of how force builds up and is released in an earthquake. An earthquake is a shaking or trembling of the earth. Earthquakes happen at the edges or boundaries of plates. The earth moves along cracks called faults. If a fault builds up pressure, when the force is great enough it suddenly releases. The result is violent shaking.
You can simulate your very own earthquake. You'll need ... your two hands! Push your hands together with all your might. Try to slide one toward you and the other away from you while you push. Eventually one hand will win. There will be a tremendous release of pressure and your hands will move apart. As long as you have all your lab supplies, simulate all three types of faults at the right.
Pele, daughter of an island goddess named Haumea, knew she was different. She was quick-tempered with red hair and eyes. Her uncle, Lonomakua, was keeper of the flames. He knew Pele would be an apt student. He taught her all his secrets of fire. Pele's sister, Namaka was goddess of the water. She was jealous of Pele and forced Pele, her bothers and other sisters out of their home. They traveled across the sea to a new place called Hawaii.
But Hawaii already had its own god named Aila'au, or forest eater. Pele and Aila'au fought for control of Kilauea. They threw fireballs, erupted volcanoes and spewed smoke at each other. When the smoke finally cleared, Pele had won. People of the Hawaii respected Pele. Legend says that if you remove lava rock from the islands Pele will curse you. She's there today you know, whenever Kilauea, Mauna Loa, or Mauna Kea, the volcanoes of Hawaii, turn on the heat.
The Hawaiian Islands were created by volcanoes. A volcano is an opening in the earth's crust where rock and steam come out. The islands are located on a plate, which is moving northwest at a rate of about four inches per year. The plate is passing over a "hot spot" or volcanic vent. This vent has been spewing lava for millions of years. The vent spews lava and creates a volcanic island. The plate moves on. The vent spews more lava, creates another island, and the plate moves on. The evidence? The oldest islands are the northwestern ones - in the direction the plate is moving.
Photo courtesy of USGS .
Shield Volcanoes form from relatively quiet eruptions. The slides are gently sloping. It doesn't really look like a classic volcano.
Photo courtesy of USGS .
Cinder Cones have a classic volcano shape. They are smaller than composite or stratovolcanoes because their explosive eruption doesn't contain much material and that material is cinders.
Composite Cones also have the classic volcano shape. They develop from alternating explosive eruptions of cinders and quieter eruptions with accompanying lava flow.
Calderas are rounded depressions formed when the ground collapses from an explosive eruption. This caldera filled with water forming Crater Lake.
Volcanic Plateaus don't look like volcanic landforms, but they are. They are flat-topped, and built of volcanic flows. Remember the buttes from earlier in this unit? Their hard, flat top is often volcanic material.Quiz Time!
Read each question and answer it in your head. Check your answer using the drop down menu option.
- What volcanoes are created from alternating violent and calm eruptions?
- What mountain building force created the Hawaiian Islands?
- Which flat volcanoes indicate quite eruptions and lava flows?
- Crater Lake is actually one of these that filled with water.
- Who is the respected goddess of Hawaii's volcanoes?
- Which volcanoes are composed of cinders rather than lava flow?
- Volcanoes are classified as active, dormant, and extinct. Which would prove the least threat to us?
- How do we know the Hawaiian plate is moving?
a Volcano 1
- 1 warm bottle or can of soda
- Go outside!
- Shake the soda.
- Open it up.
The soda explodes out of the can much like a volcanic eruption. The contents of the can are under pressure. When the pressure is released the contents rush out.