My aim is to investigate what factors affect the period of a Baby Bouncer. The factor that I will be varying will be the mass on the end of the spring.

Equipment Used

• Spring
• Clamp Stand          
• Stopwatch
• Weights
• Ruler

Method

• Equipment will be set up as in diagram above.
• The weights will be dropped from the top of the spring. The stopwatch will be started when the weights are dropped.
• We will count 5 oscillations. When the fifth oscillation has been recorded, the stopwatch will be stopped.
• This will be repeated 5 times for each mass, and we will be using weights from 100grams to 1000grams, increasing each time by 100grams.

Fair Test

To make the experiment a fair test, the following precautions will be undertook:

• The same spring will be used for every experiment.
• The same person will be operating the stopwatch, so the reaction times are the same.
• The weights must be dropped straight; otherwise they sway instead of going vertical. If the weights do begin to sway, then the experiment will be stopped immediately and repeated.

Safety

There can be safety problems while experimenting. To keep safe, we will:

• Wear safety goggles, as the springs could be dangerous to our eyes.
• Do not place hands underneath weights, as they are heavy when dropped from a high height.
• When using the heavier masses, the clamp stand is on the edge of the desk, and the weights fall down off of the sides. The clamp stand is very liable to tip over at this point, so one person must hold down the clamp stand while the experiment is in place.

Results

For 5 oscillations

For 1 oscillation

Results Graph

(On separate page)

Conclusion

From my results, I can see that as the mass is increased, the time for each oscillation is increased. This ties in with my prediction and with Hooke’s law. There is a steady curve. The graph is at its steepest at the beginning, but as more and more weights are added, the flatter the curve becomes. The graph flattens out because the elastic limits of the spring have been reached. The spring is only capable of stretching so far, and the 1000 gram weights nearly stretch it this far. If it would have been stretched to its elastic limits, the line on the graph would be horizontal with no gradient. If we were to go past the spring’s elastic limit, then the spring would be deformed, and would not be able to return to its original shape, meaning that we would not have been able to use the spring again for future experiments.

Evaluation

The experiment went well, and in the end, our results matched our prediction. The results were mainly good, and I can only spot one major anomaly, which is highlighted in blue. Although this result was an anomaly, it did not show up on the graphs. This is because we took an average on the graphs, and the rest of the results leveled the anomaly out when we took the average. The anomaly could have been there because the stopwatch was started slightly later, or maybe because the weights were swaying slightly. We could see from the results that as the force was increased, the period of an oscillation was increased. The spring did not reach its elastic limits in our experiment, as, after all of the results were taken, the spring was still at the same size as it was originally. The experiment was a success because only one variable was changed. Only the mass on the end of the spring is changed, because otherwise the results would have been more random.