Observing
Safety
As we were using masses, equipment which were quite high in the air (above the desk) and moving equipment, we were careful when participating in the tests. We used some fabrics at the bottom of the ramp so that the buggy did not come off the ramp and smash into any thing. The tests were in the presence of a qualified teacher.
Results
Measurements and Observations
Whilst we were doing the tests, we made careful measurements and observations of the apparatus and that we had measured the heights and set up the equipment properly. As we timed the buggy, we made sure that we started and stopped the stop clock on time while the buggy was in motion; this was to ensure accurate results.
Conclusion
What I found out
From this experiment I have confirmed that adjusting the height of the ramp of which the buggy travels down affects the speed of the buggy as it travels down the ramp (makes it travel faster down the ramp) also I have confirmed that when the mass of the buggy is adjusted, the speed at which it travels down the ramp is not affected (stayed the same). Increasing the mass did not affect the speed at all.
What my graphs show
My graph (graph sheet 1) shows that as I increase the height of the ramp, the speed increases, this is shown by the fact that the bars get smaller at the height increases.
My graph (graph sheet 1) shows that as I increased the mass of the buggy, the speed did not change; this is shown by the fact the bars on the graph stay level (the same).
My line graph (graph sheet 2) shows that as I increase the height of the ramp, the speed of the buggy increases, this is shown by the fact that the graph has negative correlation. My line graph (graph sheet 2) shows that as I increase the mass of the buggy, the speed did not change, this is shown by the fact that there is a horizontal line across my graph – this shows that the speed remained the same.
More about G.P.E
If we adjust the height of the ramp, and make it higher, this increases Gravitational Potential Energy. If we adjust the height of the ramp and lower it, there is less G.P.E.
Diagram
G.P.E = Mass of buggy x Force of Gravity x Height
G.P.E = 1Kg x 9.81N/Per Kg x ?cm
Therefore if the height of the ramp was 10cm high:
1Kg x 9.81 x 10cm = 98.1J
If the ramp was 30cm high:
1Kg x 9.81 x 30cm = 294.43J
Acceleration = Mass of buggy / Force of gravity
Acceleration = 1Kg / 9.81N/Per Kg
Therefore if the mass of the buggy was 100g:
100g / .981N = 101.9J
If the mass of the buggy was 400g:
400g / 3.924N = 101.9J
The above shows that as the height of the ramp increases, so does the G.P.E, and that the mass of the buggy is increased, the G.P.E stays the same. This confirms my prediction and conclusion.
Changing Variables
Height
At 10cm it took 4.47 seconds for the buggy to travel to the bottom of the ramp. At 15cm it took 3.42 seconds. This means that by increasing the height from 10cm to 26cm, the time it took for the buggy to travel the ramp decreased by 1.05 seconds.
At 25cm it took 2.51 seconds for the buggy to travel to the bottom of the ramp. At 30cm it took 2.1 seconds. This means that by increasing the height of the ramp by 5cm, it made the speed at which the buggy travelled to the bottom of the ramp decrease by a minute 0.41 seconds.
This happened because as the height of the ramp increases, the more G.P.E it gives to the buggy which will then travel down the ramp faster.
Supporting my prediction
My results backup my prediction because I said “I think that the higher the ramp is, the faster the buggy will travel down the ramp.” my results show that the higher the ramp, the faster the buggy travels down the ramp.
My results also support my prediction because I said “I think that no matter how much mass the buggy has it will always travel down the ramp at the same speed.” and my results show that no matter how we adjust the mass of the buggy, the buggy still travels down the ramp at the same speed.
Evaluation
How good are my results?
I think my results are good because there were no anomalies within them and they match my prediction.
Accuracy
We are not 100% sure of total accuracy within our results. The 1m measuring stick which we used was accurate to ± 0.5cm. The temperature of the room could be one of the factors which affects the accuracy of the results (affects the size of the ruler). The stop clock we used was accurate to ± 1/10 of a second – also ± the speed of the reaction time of the person pressing the button. The masses we used were accurate to ± 10g – this would leave us with a small margin of error, hence the dip in our results.
Strange results
We did not have any anomalies within our results; this is partly because we took an average of results, and partly down to the nature of the experiment: simple.
Testing ideas
This experiment allowed us to explore our ideas because it allowed us to interchange the masses and the heights quickly and easily. Each variant of variable was run three times so that wee could take averages. I pattern was seen in the results, expectedly.
Changes
To improve accuracy of the results:
- Do more heights and masses, like 10 instead of just 5.
- Do more averages for each height/mass of the buggy, like 10 instead of three.
- Ensure that the buggy could not run into the edge of the ramp as it travelled down, and ensure it travelled in a straight line – this caused us to have moiré friction and means that the results are not as accurate as they could be.
Reliability
If I were to repeat the experiment, I would get the same, or very similar results, so this means my results and experiment is reliable.
More experiments
If we were to do more experiments, we could repeat the whole bundle of experiments at different times of the day, or at different times of the year, when it was hot or cold for example, this could backup and confirm our results, but on the other hand, be consuming and quite pointless ☺
Improvements
To improve conditions for the experiments so that the results could be more accurate:
- Use a computer simulated run of our experiment, to backup the results.
- Use light gates so that the times are as accurate as possible.
- Use laser measurement equipment to get the distance of the ramp.
- Use electronic scales to measure the masses, so ensure they are accurate.
Future experiments
If we were to repeat these experiments to further support our conclusion, we could do the same experiments with the above improvements but use more variables and run them and take times for ten experiments instead of three. This would give us a broader, more accurate range of results which we could use to confirm the conclusion.