Buggy Lab (Example)
Purpose: To determine the graphical and mathematical relationships between position and time for a toy buggy moving at a constant speed.
Hypothesis: As time increases, the position of the toy buggy increases at a constant rate.
Parameters: Starting positions (m) and car number.
Independent Variable: Time (s)
Dependent Variable: Position (m)
Equipment: Toy buggy, measuring tape, stopwatch, masking tape, meter stick (optional)
Procedure: Stretch out the measuring tape to at least 5m.
Part1: Place the buggy at the 0m mark pointing forward. Start the timer and let the buggy go at the same instant. Measure the buggy’s position in meters every second for 10s. Repeat two more times.
Part2: Start the buggy at position 5m pointing backward. Start the buggy and stopwatch at the same time. Measure the buggy’s position in meters every second for 10s. Repeat two more times.
Measured: The measuring tape measures the position of the buggy in meters. The stopwatch measures the time in seconds.
Data: (Should be written in pencil. Lines should be drawn using a straightedge).
Forward: Parameters: Car 3, Starting Position 0
Time (s) / Trial 1 (m) / Trial 2 (m) / Trial 3 (m) / Average Position (m)1 / 0.26 / 0.28 / 0.27 / 0.27
2 / 0.54 / 0.55 / 0.55 / 0.55
3 / 0.80 / 0.76 / 0.77 / 0.775
4 / 1.04 / 1.01 / 1.01 / 1.02
5 / 1.30 / 1.31 / 1.29 / 1.30
6 / 1.55 / 1.60 / 1.56 / 1.57
7 / 1.85 / 1.90 / 1.87 / 1.87
8 / 2.12 / 2.16 / 2.14 / 2.14
9 / 2.40 / 2.43 / 2.42 / 2.41
10 / 2.69 / 2.68 / 2.70 / 2.69
Backward: Parameters: Car 3, Starting Position 4m
Time (s) / Trial 1 (m) / Trial 2 (m) / Trial 3 (m) / Average Position (m)1 / 3.72 / 3.72 / 3.74 / 3.73
2 / 3.46 / 3.45 / 3.45 / 3.46
3 / 3.19 / 3.18 / 3.20 / 3.19
4 / 2.90 / 2.93 / 2.93 / 2.92
5 / 2.66 / 2.65 / 2.65 / 2.65
6 / 2.36 / 2.41 / 2.39 / 2.38
7 / 2.08 / 2.15 / 2.12 / 2.11
8 / 1.77 / 1.90 / 1.85 / 1.84
9 / 1.50 / 1.65 / 1.56 / 1.57
10 / 1.11 / 1.28 / 1.19 / 1.19
Evaluation of Data:
Average Calculation:
At t=1s moving forward, Average Position = (0.26s + 0.28s + 0.27s)/3 = 0.27s
(One calculation is necessary. The rest of the values can be put in a table in the “Data” section).
Slope Calculation: m=y2-y1x2-x1 =2.690-0.27010-1=0.269ms
Y-intercept Calculation: y=mx+b
1.57m=(0.269m/s)(6s)+b
1.57m=1.61m + b
b = -0.04m
Math Model: x = (0.269m/s) t
General Equation: x = vt + x0
Slope Calculation: m=y2-y1x2-x1 =1.570-3.4609-2=-0.27ms
Y-intercept Calculation: y=mx+b
1.570m=(-0.27m/s)(9s)+b
1.57m=-2.43m + b
b = 4.0m
Math Model: x = (-0.27m/s) * t + 4.0m
General Equation: x = vt + x0
Conclusion:
While the toy buggy was moving in the positive direction, we found that as time increased, position increased and that position was directly proportional to time. As time increased by 1s, position increased by 0.269m.
While the toy buggy was moving in the negative direction, we found that as time increased, position decreased at a constant rate. As time increased by 1s, position decreased by 0.276m.
This proved our hypothesis incorrect since position did not increase as time increased when the buggy was moving in the negative direction.
The general equation for the motion of the toy buggy was x = vt + x0 where x is position, v is velocity, t is time, and x0 is initial position.
The y-intercept is x0, the initial position, which is the position of the buggy when time is 0.
The slope, v, is velocity, which is speed and direction. Position is the location of an object. Distance is how far apart two objects are. Initial position is the location of an object at time 0.
Error Analysis:
The biggest source of error was lack of precision in measurements. The stopwatch may have started slightly before or after the buggy was released. Also, it was difficult to measure the position precisely without more sophisticated equipment. Finally, we assumed the buggy traveled at a constant speed in a straight line, but ours turned slightly to the right as it drove.