Food From The Sun (1966)

[Music] this is a story of how plants and animals get energy from food about how wild geese who travel hundreds of miles in a day get energy to fly so high and so far while migrating geese use a great deal of energy a caterpillar needs much less but still some energy is used even to move an inch just growing as well as moving takes energy even when a squirrel is not moving its heart and lungs are hard at work energy is needed for every kind of work whether it's flying crawling rowing or just living how do animals get the energy they need they get it from food how much food they need depends on how much energy they use the hummingbird is very active what it eats in one day weighs more than the bird itself such animals as alligators and turtles spend much of their time resting and for their large size they eat relatively little a fox like many animals gets energy by eating smaller animals while other living things may eat different kinds of food [Applause] a caterpillar for example eats only green plants some of the larger animals are also plant eaters but plants are living things too do they need energy with a special camera we can see that this Bean Sprat must push through the soil to grow though plants grow and move slowly they use energy all the time to stay alive so plants must need food too where do they get their food what does a green plant need to stay alive and grow it needs air it needs minerals from the soil it needs water but green plants need something else they must have light though a plant needs air minerals and water these things are not food in themselves they have no energy to give so where then do plants get their energy we know that animals get theirs from eating other living things but green plants cannot do this instead they make their own food and this is one of the big differences between plants and animals how can plants make their own food they do it with the help of energy from the Sun how do we know the sun has energy let's investigate with a simp simple demonstration these cells are sensitive to light when sunlight falls on them they change light into electrical energy which turns the disc what happens when we cover the cells sunlight shining through this sealed glass bulb gives us further proof that the sun transmits energy so there is energy in the sunlight falling on this Leaf energy that green plants need in order to live what happens to green plants that do not get light this board has covered grass which seems to have stopped growing is it because it did not receive sunlight perhaps we can find out with a simple experiment these two pots have seeds planted in them they both have soil air and water only now one will be cut off from the light will it grow as well a few weeks later one is growing the other barely surviving so it seems that somehow green plants depend on sunlight to live with energy from the Sun green plants change air water and minerals into food food for themselves and food for other living things how do cows depend on energy from the Sun how does a squirrel depend on the sun corn is another food the sun helped to grow sometimes we feed corn to chickens how do chickens get energy from the Sun playing takes a great deal of [Music] [Music] energy how do we get energy from the Sun some of our energy comes directly from plants from the fruits and vegetables we eat some comes from animals the energy we use to live and grow comes from Foods produced by energy from the Sun a super market is in a way a storehouse of the sun's energy a storehouse where we go to get energy for ourselves all living things depend upon the Sun for Life the sun which helps the corn grow tall which ripens apples in the fall the Sun for grass that cattle eat which gives us milk and cheese and meat the Sun that has so much to give without the sun we could not live [Music]