Fred's Fan Experiment

Experimental Design and Review

Fred studied electric fans to see which fan produced the greatest wind force. He tested four different brands of fans; Remington, Twister Fan, BlownAway, and FANS-R-US. Each brand was tested two times and the results were averaged. All fans used 120 volts and were run on the high setting. To measure the wind speed, he used a wind gauge which was placed 30 cm from the center of each fan. The fans were turned on and allowed to warm up for one minute before the wind gauge test was conducted. All the fans tested had diameters of 35 centimeters. Three fans had four blades and the BlownAway Fan had three blades. Fred determined that the Remington fan produced the most wind.

Fred's Data:

Remington Fan: Average speed 6 meters per second

wind speed 5 meters per second and 7 meters per second

Twister Fan: Average speed 4 meters per second

wind speed 2 meters per second and 6 meters per second

BlownAway : Average speed 5.5 meters per second

wind speed 6 meters per second and 5 meters per second

FANS-R-US Fan: Average speed 5 meters per second

wind speed 9 meters per second and 1 meter per second

Fred's experiment has some flaws. What could he do to make his experiment better?

Fred should have only tested fans with four blades. The BlownAway fan only had three blades so he introduced a second variable into the experiment besides the brand of the fan.

Fred should have also tested each fan more than two times. Two times is not a significant amount to base a conclusion on.

Fred should check his wind gauge. In several cases the results varied wildly. In the FANS-R-US experiment; how could he get 9 meters one time and 1 meter the next for the same fan?

Can you also identify the independent variable?

The independent variable is the one thing that Fred is changing on purpose to see how it affects the experiment. In this experiment it was the brand of the fan.

Can you also identify the dependent variable?

The dependent variable in this experiment is the wind gauge reading. It depends on the brand of fan you are testing. The wind gauge numbers vary depending on which brand you test.

What was the purpose of the experiment or what problem was Fred trying to answer?

The purpose (problem) of the experiment was to find out which fan produced the greatest wind.

What were the controls in Fred's experiment?

The Controls of Fred's experiment were the things that he kept the same to make the experiment fair for all the fans being tested.

1. All fans were tested two times.

2. All fans tested were 120 volts.

3. All fans were run on the high setting.

4. The wind gauge was always placed 30 centimeters away,

5. All the fans tested had diameters of 35 centimeters.

6. All the fans tested were allowed to warm up for one minute.