Physics coursework; Spinners

Introduction

My investigation is about how the number of paperclips added onto a paper spinner affects the time taken for the spinner to fall from a height of 3m. I predict that the time taken for the spinners to fall to the ground will decrease when the number of paperclips added increases. This is because heavier objects fall to the ground faster than objects that are lighter. The force of gravity is directly proportional to the mass of the object. The equation to measure the force of gravity is :

Fg                      =   M      x    Ag

Force due to gravity    =    mass      x       acceleration due to gravity (-9.8m/s)

Forces

To find out what is going to happen to the spinner when it is dropped from a height you have to look at what forces are acting on the spinner. There is always one force that acts on everything on earth and the force id called gravity. Gravity is a downward force that attracts everything on earth to its centre or core. The force of the gravitational pull is equivalent to the weight of the object. Theoretically the higher the weight the greater the force of gravity, so the spinner should fall to the ground quicker with more paperclips on it.

There is also another force called air resistance that pushes up on the spinner and when it falls.  Objects with a large surface area have a greater force of air resistance so the time they take to fall will be more.

Spinner

Preliminary results

Results table

For the first experiment no weight was added to the spinner so the weight is 0 grams but the spinner did have a weight. Each paperclip weighed 0.43 grams each so the added weight increases by 0.43 when a paperclip is added. The ‘average time’ in the graph represents the time taken for the spinner to fall to the ground. The weight of spinner is the added weight of paperclips.

Result graph

Data analysis and interpretation of preliminary results

When the spinner is dropped from a height it starts to spin as it is dragged down to the ground by the force of gravity. The force of gravity when the spinner is stationary

The average results decrease almost steadily and slowly until the fourth paperclip is added with a maximum decrease in time of 10 seconds. There is a 0.31 second difference from the fourth to the fifth paperclip; this could be due to wind as the window was not closed. It could not have been because of the wing span, material or weight because we used the same spinner for all the experiments and the weight is the independent variable so it has to change and I do not  believe it was easy to make mistakes with adding the weight. The only other explanation is that the height it was dropped from was different which is possible because I had to reach up to get the spinner to reach 2 metres. This could account for small changes that do not fit the trend, like the anomaly for the fifth paperclip.

The small differences in time taken to fall to the ground are probably due to the time it takes for the person to hit the start and stop button on the stopwatch and the slightly large differences are because of the person dropping the spinner is not timing the fall, so if he timed the fall instead of the person watching then we can get results that have a smaller range.

The graph shows quite a line of best fit with the plots close to it which is why there is a good r squared value of 0.9934 and the graph shows a negative correlation between the weight increasing and the average time taken for the spinner to fall. Because the r squared value is also good this supports the correlation that my graph shows and the theory that as the weight increases, the time it takes for an object to fall to the ground decreases.