In this activity, students test various vegetables to see if they give off an electrical charge. It is most appropriate for older elementary and middle school students. Students should chose from a variety of vegetables and a couple of kinds of fruits. They should have several samples of each type of fruit or vegetable -- some fresh and some older. Students use an amp meter to measure the electrical charge each vegetable has. They should measure the current flow using the micro amp scale on the meter, and measure resistance using the ohm scale. Discuss their findings -- resistance should be less for vegetables with more water in them; while acidic vegetables will register the greatest current.
This science activity gives students some hands-on experience in the parts of a plants. It is appropriate for students in middle school and older elementary students. Let students choose from a variety of vegetables. Students choose a vegetable and use a magnifying glass and a child-safe knife to locate the vegetable's different parts. Students can then discuss how each plant is adapted to its habitat. Older students can prepare tissue slides from their vegetable and examine the slides under a microscope.
Here, students can practice laboratory techniques while making a useful product. Remove the skins from yellow, white and red onions and keep each color skin separate. Fill three pots with around three cups of water each and add one type of skin to each pot. Bring the water to a boil and boil the skins for 10 minutes. You can also place the skins in glass containers and heat them in a microwave on high for five minutes. Allow the water to cool, and strain the dye to remove the skins. Dip white cotton cloth in each dye to check the color. Repeat the activity, this time boiling for 30 minutes. Discuss whether the length of boiling time affects the color of the dye and whether the dye color was the same for each type of skin.
This activity is appropriate for elementary school students. Give each student three stalks of celery and three cups of water. Students should add one tablespoon of sugar to one cup and one tablespoon of salt to a second cup -- leaving the third cup with plain water. They then add about 10 drops of food coloring to each cup, using a different color in each cup. Students place each celery stalk into one of the cups of water and leave the stalks for two hours or more. Remove all of the celery from the water and peel it to expose the inside of the celery. Students should see colored lines on the inside of the celery. These are capillaries. Discuss how the celery absorbs water through the capillaries and whether sugar or salt makes any difference in the rate of absorption.