Photosynthesis

What is Photosynthesis? The word photosynthesis can be separated to make two smaller words: “photo” which means light “synthesis” which means putting together Plants need food but they do not have to wait on people or animals to provide for them. Most plants are able to make their own food whenever they need it. This is done using light and the process is called photosynthesis.

Photosynthesis is the process by which plants make their own food.

To make food plants need: - carbon dioxide - water - sunlight

Let’s take a look at how these are collected by plants.                                                          Carbon dioxide from the air passes through small pores (holes) in the leaves. These pores are called stomata. Water is absorbed by the roots and passes through vessels in the stem on its way to the leaves. Sunlight is absorbed by a green chemical in the leaves.

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The Process of Photosynthesis Photosynthesis takes place in the leaves of plants. The leaves are made up of very small cells. Inside these cells are tiny structures called chloroplasts. Each chloroplast contains a green chemical called chlorophyll which gives leaves their green color.

Chlorophyll absorbs the sun’s energy. It is this energy that is used to split water molecules into hydrogen and oxygen. Oxygen is released from the leaves into the atmosphere. Hydrogen and carbon dioxide are used to form glucose or food for plants.

Some of the glucose is used to provide energy for the growth and development of plants while the rest is stored in leaves, roots or fruits for later use by plants. Here is the process in greater detail: Photosynthesis occurs in two stages commonly known as Light dependent Reactions and the Calvin Cycle.

Why is Photosynthesis Important? Photosynthesis is important because it provides two main things: - food - oxygen

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EXPERIMENT !!!!!

The Importance of Leaves Now you can understand what a plant needs to complete photosynthesis. This experiment can help you to learn about the parts of a plant involved in this process. You'll need: Plants Paper String Scissors Directions: The students should cut some shapes out of their paper. You can use whatever shapes they'd like, but you shouldn't be much larger than the leaves of the plants. Have the kids place the paper over some leaves on the plants. They can use string to secure them if they need to. Have them leave these shapes on for several days and then remove them. Discussion Points: What happened to the leaves? They should be faded and drooping beneath the paper, where they couldn't get any sunlight to complete photosynthesis. You can continue this experiment by having your students note the number of days it takes for the leaves to recover. Students can focus on finding out more about leaves and their role in photosynthesis with this lesson on the structure of leaves.

FINALLY… Answer these questions: - When you think of the sun, what do you think of? - What are some fun experiences you have with the sun?  Share them with a peer in class. - Do you think the sun is important?  If so, why?  If not, explain why? - Do you think we could live without the sun?  Why, or why not?  - When you look at the word photosynthesis, can you see the prefix photo? _ Do you know what photo means?  Can you make a guess?