How can a cave form from solid rock? Most caves are found in limestone, a rock made of materials of calcium carbonate. This rock is unusual because the solid minerals it is made of easily dissolve in weak acids. The most common weak acid in the environment is actually water!
What is sea ice? It is simply frozen ocean water.
Why is sea ice important? While it occurs mainly in polar regions, sea ice influences our global climate. Changing amounts of sea ice can affect ocean circulations, weather patterns, and temperatures around the world. Sea ice insulates the relatively warm ocean water from the cold polar atmosphere, except where cracks in the ice allow for the exchange of heat and moisture. The exchange of salt between sea ice and the ocean alters the density of ocean waters, thus influencing ocean circulation. Many animals, such as polar bears, seals, and walruses, depend on sea ice for their habitat. These species hunt, feed, and breed on the ice.
Satellites provide the best way to observe sea ice, the factors that affect sea ice, and the ways sea ice affects global climate. Scheduled to launch in 2010, NASA’s Aquarius mission will measure global sea surface salinity with unprecedented resolution. Even small variations in sea surface salinity — the amount of salt present near the ocean’s surface — can have dramatic effects on sea ice, the water cycle, and ocean circulation.
This activity from the Environmental Protection Agency will give children the opportunity to see how changes in sea level effect coastlines, animal life, and community development.
Scientists use seismic technology to map patterns of rock formations below the surface of the Earth. Different types of rocks affect sound waves. Geologists use these sound waves to locate rocks that may contain oil and/or natural gas.
You can explore this principle with a tuning fork and various rocks. Gently strike a fork against the rocks. Note variations in sounds produced by different rocks. How could scientists use this information to help map the rock layers underground? In the following activity, you will explore one way scientists find oil beneath the Earth’s surface.
Earth processes such as volcanic eruptions, floods, landslides, and glaciers leave behind evidence of their passing in the form of layers known as deposits. By studying deposits of recent geologic events, geologists are able to better understand older deposits and identify the processes that caused them.
In this activity, learn how sinkhole formations in rocks form and the danger they pose to communities.
In this activity, students will conduct experiments or participate in demonstrations to answer questions about sky and weather phenomena. Students also will analyze and present data.
Where is the water in soil? Solids, liquids, and gasses, the three phases of matter, are always present in soil. Small mineral and organic particles comprise the solid fraction, and there are spaces (pores) between the solid particles. Some pores are large, and others are very small. Air and water, the gas and liquid phases, exist in the pores. The size of the soil particles and pores affects how much water a soil can hold, and how that water moves through the soil.
Discover more about soil properties in this excellent outdoor activity from the National Park Service!
Soil is often overlooked as a natural resource. Like fossil fuels, we depend on it for energy in the form of foods. And, like fossil fuels, it is nonrenewable. Soil is a delicate balance of inorganic minerals, organic matter, living organisms, soil water, and soil atmosphere. The natural development of soil is an exceedingly slow process. In a few hours, a heavy rain falling on exposed soil can remove inches of what took hundreds of years to form. Here is a simple exercise that will allow you to compare the rates and amounts of erosion that result from various land uses.