What are some of the most important organisms on Earth? GREEN PLANTS! Plants provide oxygen for the atmosphere and at the same time clean up pollutants in the air such as carbon dioxide. What better month than March — with its first day of spring — to explore the power of plants!

Which Way Do I Grow?

Conducting an experiment, understanding geotropism

Do seeds know which wayis up and which way is down? To find out, enlist student volunteers to help you conduct the following experiment.

Supplies: glass jar with screw lid, 6 paper towels, water, 2 green bean seeds soaked in water overnight

Directions:
Step 1: Roll up six paper towels and place them in the glass jar.
Step 2: Moisten the paper towels with water.
Step 3: Insert two bean seeds between the paper towels and the glass so that each seed is visible from the outside of the jar as shown.
Step 4: Place the jar in a warm, sunny area. In about three days, observe the roots beginning to grow down from the seeds as shown. Keep the paper towels moist.
Step 5: When the roots are about one inch long and a shoot begins to push out of the top of the bean, screw the lid on tight and turn the jar upside down.
Step 6: Observe and record the growth of the roots and the shoots.

After three or four days, the roots turn and grow downward in a positive response to gravity. Meanwhile, the stems turn and grow upward in a negative response to gravity. This built-in growth response in plants is called geotropism.

Honey, I Blew Up the Plants

Observing plants, writing for a purpose

Allow your students to take a closer look at the plants they pass each day. Supply each student with a magnifying glass, two sheets of notebook paper, and a pencil; then take the class outside. Inform each student that he will be using the following KWL technique to observe each plant:

• K — Write down what you know about the plant.
• W — Write down what you want to learn about the plant.
• L — Write down what you learned about the plant after completing your examination.

Instruct each student to select a plant to examine using the magnifying glass. Suggest such plants as grasses, evergreens, or other spring-blooming plants that are emerging in your schoolyard. Instruct the student to observe the plant in its location and not to pick the plant or damage it. Have each student use the KWL method to record his observations on the first sheet of notebook paper and then illustrate his plant on the second sheet. Return to the classroom and have each student present his observations and illustration. Post these findings around the classroom for the duration of your plants unit.