Our Round Earth - its Land (1971)

the land looks hard and dry hardly any plants mostly Solid Rock many parts of the earth's land show Mostly Rock in some places the rock may be in giant slabs in other places the rock may have cracked into smaller Boulders Boulders in turn May Crack or be worn down into smaller stones and Pebbles on a desert rock Rock has broken into even smaller pieces into fine grains of sand each grain of sand is a very tiny bit of rock Sand by itself isn't so good for growing things a part of the earth's land that's much better for growing things is soil soil is a mixture of sand and clay and bits of plant and animal matter soil is one of the most important parts of the earth's land do you know why soil is needed to grow crops these food plants wouldn't be here without soil C cattle from which we get our meat wouldn't be here without soil either cattle feed on grass and grass grows in soil can you see how we depend on soil for the milk we drink can you see how we depend on soil for the fruit that we eat and what about the wood we use none of these things can grow without soil you may know that only a small part of the land is made up of soil just the top few inches or so and what's below the soil below the soil we find clay sand gravel and solid rock rock is what most of the earth's land is made of this is a rock quarry where rock is mined Rock by itself is not as important as soil but it has many uses rock is used in building construction crushed rock mixed with sand and cement forms concrete probably the most widely used building material other uses for rock have to do with minerals that make up the rock you can see different kinds of minerals in this rock these minerals have formed tiny crystals large attractive crystals of some minerals are known as gems these include diamonds sapphires rubies and emeralds here's a mineral not so pretty as the gems we've seen but in some ways it's more valuable this is salt that's right the kind of salt you use on food Salt is another important mineral that comes from the earth's land other important minerals include Metals this mineral contains the metal lead this one contains gold another metal this rock contains another metal iron many different kinds of metal come from rocks rocks which are dug from the lands of the Earth can you think of other useful substances buried in the land core l large amounts of coal from the Earth are burned to generate electric power coal is also used to make steel another fuel found in the Earth is oil giant drills are used to dig Wells thousands of feet into the Earth pumps are then used to bring oil to the surface where it can be used to find more oil men have begun drilling wells in the sea such Wells go below the water into land at the bottom of the ocean land lying below the Earth's oceans contains valuable materials that have hardly been used because they're so hard to get at parts of the sea bottom are covered with loose sand and soil soil which has been washed into the ocean from the shore large amounts of soil are carried into Oceans by Rivers soil is washed into rivers by heavy rains that pour over the surface of the land it takes thousands of years for soil to form yet it can be washed away in just a few years if it's not protected how can soil be protected how can men conserve soil so it won't be washed away how can men conserve other materials from the land what can be done for instance with Cinders and Ashes left over from coal after it's been burned what can be done with things made of metal once men are through with them what can be done with paper glass and other materials from the Earth are there better ways of getting rid of these materials are there ways of using them again what can we do so that the lands of the earth will continue to supply us with the things we need how can we make the best use of the lands of our Earth