The Earth and Its Movements
The earth is in constant motion. The first two, and more noticeable movements are that which turn day into night, and which bring the seasons. Day and night is the effect of the earth spinning or rotating on its axis every twenty-four hours. When the earth faces the sun it is daytime on one side and night on the other, as it rotates, day and night shift. This is also the reason behind time differences. The second movement is the earth's rotation around the sun. It takes 365 and ¼ days for the earth to complete its orbit around the sun. Depending on the position of the earth, how far away it is from the sun, the seasons change accordingly, making it either cooler or hotter.
Studying the earth's movements is science made fun. From the above mentioned movements alone, many science projects can already be thought up. These two are not the only movements of the earth, though, and the other movements on earth can be found deep within it.
Reviewing the parts or layers of the earth, you should remember that there is an inner radioactive core which is a source of incredible heat. Some scientists also speculate that the radioactivity is what causes the earth to rotate on axis. After the inner core is the outer core, which is also very hot. Next comes the mantle, also divided into upper and lower. The mantle is mostly composed of a burning liquid rock known as magma. We see magma or lava when a volcano erupts. This magma is constantly moving, like underground rivers of liquid fire. Finally, the earth's crust is what covers all of this, but this crust sometimes be moved by large pieces of land known as “plates.”
The theory of plate tectonics is a lot of science made fun. It theorizes that the earth's crust is sometimes divided into plates. These plates can move (some theorize on the rivers of magma) and reshape the earth. Some people believe that the land on earth was once all connected, and the plates began to move away from each other causing the land to split and create the many different islands and continents.
Today the effect of moving plates is best seen through earthquakes, which is considered to be any seismic event that happens on earth. Some plates have created fault lines or cracks in the earth, and when these move against, towards, or away from each other, the earth shakes or tremors, and the tremors are felt at the surface. Sometimes we see the effects of earthquakes that occur out at sea when huge waves known as tsunamis come crashing into shore. The study of earthquakes is also science mad fun. In the projects section, you will find out how to create an earthquake diorama and study the effects of earthquakes on earth.