The theory of plate tectonics describe the large motions of Earth’s lithosphere, made up of ridges and trenches that move on the Earth's crust. This theory is based on the concept of continental drift, and the evolutionary ideas are complex. Scientists and oceanographers monitor how continents are able to move around by using modern technology. They employ advanced equipment to map and measure the ocean floor in order to explain how the earth has formed and continues to change. To help kids understand the causes and effects of evolution on plate tectonics, scientific videos, visual explanations, and creative projects can help.
According to the Continental Drift theory, the Earth was made up of a single continent over most of geologic time which eventually separated into what we now call our continents. These seven continents drifted apart. According to German meteorologist Alfred Wegener, the lighter rocks that make up the continent rest on heavier crusted material making them move very slowly through water. This is thought to be at a rate of one yard per century. Scientists believe that the Earth’s surface is broken into a number of shifting plates that lie between these continents and are about 50 miles thick. These lie in North America, South America, Eurasia, Africa, Indo-Australia, Pacific, and Antarctica. These plates move relative to each other, sometimes at an average rate of a few inches per year.
Ridges and trenches
On the seabed, almost exactly halfway between continents, lie raised areas known as ridges. These ridges are similar to mountain ranges but are located deep beneath the waves. Scientists have also found extremely deep trenches that can stretch to thousands of feet deep. The ridges, many scientists say, demonstrate areas where new crust is formed as hot magma is released from the Earth's core. The seafloor then spreads outward from the area where the magma escapes, making the continents also move outward across the sea, on top of the lower layer or the 'sima crust'.
Fault lines and volcanoes
The location where the plates meet is known as the fault lines. The movement of the plates can cause one plate to move under the other - underthrusting - or moving apart - spreading. A strike-slip fault is where the plates slide horizontally past one another. Most of the world’s active volcanoes are located along or near the boundaries between the shifting plates. These are called plate-boundary volcanoes. The peripheral area of the Pacific Ocean Basin contains the boundaries of several tectonic plates. This is dotted with many active volcanoes and is therefore known as the Ring of Fire.
Pictures, maps and charts
Help kids understand the theory of Plate Tectonics by drawing examples of how the plates move against one another. This can help kids visually understand a complex concept that is not visible in daily life. Make a cross-section of what happens on the seabed and label each part clearly - ridges, trenches, magma, and the Earth's core and crust - to explain the details of the topic. Use a map to explain where the fault lines lie.
Using Plasticine or clay, help kids create models of the different elements. Have them use different colours for each section and make three-dimensional volcanoes and ridges to understand the movement of the tectonic plates. With the use of moving parts and layers, kids can understand how continents on top of the tectonics will inevitably move if magma is released. Making models by hand will help children understand about the formation of mountain ranges, volcanoes and the processes that take place on the Earth.