photosynthisis

BY lilly G

what it is

Photosynthesis may sound like a big word, but it's actually pretty simple. You can divide it into two parts: "Photo" is the Greek word for "Light," and "synthesis," is the Greek word for "putting together," which explains what photosynthesis is. It is using light to put things together. You may have noticed that all animals and humans eat food, but plants don't eat anything. Photosynthesis is how plants eat. They use this process to make their own food. Since they don't have to move around to find food, plants stay in one place, since they can make their food anywhere as long as they have three things.

what you need to know about photosynthisis

  • Humans and animals do the exact opposite of photosynthesis. They breathe in oxygen and breathe out carbon dioxide. This means that we give plants more carbon dioxide, and they give us more oxygen. Without plants we wouldn't be able to survive, but there is enough carbon dioxide in the atmosphere that plants would still exist without us!
  • Before there was photosynthesis, there wasn't much oxygen in our atmosphere. So before plants evolved the ability to turn water and carbon dioxide into sugar and oxygen, there was no way for plants and animals to exist. Before photosynthesis, bacteria and other living things used other chemicals to make their food. But when photosynthesis started, it worked really well, so organisms (living things) that had photosynthesis thrived and evolved into plants and trees. As more plants grew across the planet, more and more oxygen went into the atmosphere, meaning that animals were able to start evolving! We would never have existed without photosynthesis.
  • The atmosphere is full of carbon dioxide. Carbon dioxide is a greenhouse gas, meaning that if it is in the atmosphere, it holds heat close to the earth, which makes our planet warm. If we didn't have carbon dioxide, we wouldn't be a warm planet, we would be cold like the moon. If we had too much carbon dioxide, we would be like Venus, which is a really hot planet. Plants keep our atmosphere from getting too much carbon dioxide and heating up by turning a lot of it into oxygen.
  • how do plants capture sun light

    Plants capture sunlight using a compound called chlorophyll. Chlorophyll is green, which is why so many plants appear green. You might think at first that it's green because it wants to absorb and use green light. However, from our study of light, we know that the color we see is actually the color of light that is reflected. So chlorophyll actually reflects green light and absorbs blue and red light.

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