1. CONDUCTING A CONTROLLED EXPERIMENT You perform an experiment to test a hypothesis. Controlled experiment includes 2 set ups. When you do a controlled experiment set-up: 1. CONTROL SET-UP: Contains all the factors (parameters) except the one you will be testing. 2. EXPERIMENTAL SET-UP: It is set exactly the same way as the control set up (has all the parameters) and one variable only, the one you will be testing.

2. EXAMPLE Controlled Experiment CONTROL SET-UP EXPERIME NTAL SET- UP TESTING THE EFFECT OF FERTILIZER BRAND A ON THE GROWTH OF BEAN PLANTS. Work in pairs and design an experiment to test the effect of the fertilizer brand A on the growth of bean plants. LISTall the parameters (table).

3. CONTROL SET-UPEXPERIMENTAL SET-UP Amount of sunlight Pot size and material Same type bean seeds 1/3 cup of water per pot per 2 days Temperature Soil type Same “area” 10 plants growing All factors must be the same as control set-up except add 1 teaspoon of fertilizer to each pot. PLANT 10 seeds

4. CONTROL SET UP The results of the control set up is used as a standard for comparison. The results you obtain from the experimental set up is compared with the results of the control set-up in order to see if the variable you have tested has any effect on the results. Any change in the results of the experimental set up is due to the variable you have tested ONLY TEST ONE VARIABLE AT A TIME IN EACH EXPERIMENT!