Two different experiments are presented, each experiment using a different pair of models:
Experiment 1: Models A and B, where A is the control, and the cover (B) is the variable.
Experiment 2: Models B and C, where B is the control, and water (C) is the variable.
Your teacher will tell you which experiments to do and which models to use. Directions for
building the models are given on the next page. Note: Prepare each model out of direct sunlight.