Some poinsettia plants have green leaves that turn red. A garden club decided to study the color change of poinsettia plants. Knowing that poinsettias change color during the short daylight periods of winter, they decided to investigate the effect of different daylight lengths on color change. Design a controlled experiment using three experimental groups that could be used to determine if the number of hours of daylight has an effect on the color change of poinsettias. In your experimental
design, be sure to:
• state one hypothesis the experiment would test [1]
• state one way the three experimental groups would differ [1]
• identify two factors that must be kept the same in all three groups [1]
• identify the dependent variable in the experiment [1]
• describe experimental results that would support your hypothesis