Does More Powerful Really Mean More Power?

Physical Science

John KellyHugo Suarez

Problem Statement

Does an electric motor that is sold as being “more powerful” really provide more power?

Power is defined as the ability to do work

The project will use the ability to move an electric buggy across the floor as a measurement of work.

Project Overview

The project will compare the power of 3 different motors by measuring the distance traveled by an

electric buggy in a set period of time.

Variables

Independent variable: The type of motor (weak, medium and strong) Dependent variable: The distance traveled (in meters) by the buggy in 5

seconds

Constant variables: time (5 seconds), location - floor surface, same vehicle

Control group: Medium Motor because it was the average between the small and large motors.

Hypothesis

Small, hobby type electric motors cost more for motors that are considered to be more powerful. In Science Olympiad competitions it was observed that vehicle design has more to do with vehicle speed than the type or size of motor used.Hypothesize: if a larger motor is used then it will not travel as far as the other motors because the motors are sold as more powerful do not actually provide more power in all situations.

Materials

1 electric buggy 3 different power electric motors (weak, medium, strong) 6 volt power supply Timer Metric measuring tape

Procedure1. Place vehicle at starting point2. Start timer and vehicle at same time3. At 5 seconds mark location of vehicle on floor with

masking tape4. Measure distance traveled from starting point with

metric measuring tape (in meters).5. Record distance in data table.6. Record distance for a total of 5 trials.7. Install a different motor in vehicle.8. Repeat steps 1-7 to collect data for the three

different motors

Data/ObservationsAnalyzes

motor 1 motor 2 motor 3trial Weakest Middle Strongest

1 6.7 7.6 4.92 5.8 5.8 5.53 5.5 5.5 5.84 3.9 3.9 5.25 5.2 5.2 7.0

Average 5.70 5.60 5.68

distance traveled (m)

Data/ObservationsAnalyzes

0.001.002.003.004.005.006.00

1 2 3

dist

ance

(m

)

motor

Motor Comparison

Conclusion

Based on the results of our experiment, our hypothesis was correct. In this experimental set up there was no difference in the power provided by the three motors. Each motor was able to power the buggy essentially the

same distance (within 10 cm) in the 5 second time limit.

Possible Experimental ErrorsThere were some values for distance that were

inconsistent with the other measurements we took for the distance values. For example, motor 1 had a measurement of 3.9 meters and one distance of 6.7 meters. All other measurement were close to

each other. The most likely reason for these would be an error in marking the vehicle location when time stopped or starting the timer and the

vehicle at the exact same time. By conducting multiple trials and using the average of the trials

the results are close to actual and reliable numbers.

Applications and Recommendations

The results are only valid for motors used to operate a small, light weight vehicle on a smooth and level surface. If experiments were conducted using heavier vehicles, uneven surfaces or climbing up a hill the results could be different and would justify buying a more powerful motor for those situations.