BACKGROUND:

The plant kingdom includes seed plants, ferns and mosses. Plants can have one cell or many cells. Plants make their own food by producing simple sugars through a chemical process called photosynthesis. Most of the food produced by plants is made in the leaves. The leaves provide ample surface area for the absorption of light energy and contain many chloroplasts and it is in the chloroplasts where photosynthesis occurs.

Leaves are often modified to help the plant in other ways. Cactus leaves, for example, have spikes to protect the plant, and most of the food production occurs in the stem. Some leaves are waxy to help conserve water, and some are hairy, making them less palatable to animals. Venus fly trap leaves help capture insects, which provide nitrogen to the plant.

Roots help anchor the plant to a substrate and draw water and minerals from the soil. Some roots form a shallow network underneath the soil surface, while others have tap roots that can go quite far down to find water and anchor the plant.

We eat a number of different kinds of leaves and roots. We eat the leaf blades of spinach and lettuce, and the stalks of celery leaves. Onions are layers of leaf bases (the lower part of the blade) that have been modified to store food for the plant. Carrots and radishes are examples of roots we eat.

PROCEDURE:

1. Ask your students why they think plants have roots. Mention the different kinds of roots and discuss why it is so hard to pull up certain plants such dandelions which are anchored by their roots.
     
2. Show different kinds of leaves and have the students notice the different patterns of veins, different leaf edges, and overall shapes and sizes.
     
3. Ask the children why plants have leaves and talk about a plant's ability to make food and how this makes it different from an animal.
     
4. Show the students how to make a leaf rubbing, by using the broad sides of their pencil leads or crayons. Use news stock, onion skin, or other soft paper. Put the leaf under the paper and softly rub the crayon over the leaf. Have them notice how the veins and leaf edges come through. Let them make rubbings of a number of different leaves. Talk about foods from leaves and roots and show them some examples.