elastic band experiment

Gravity pulls things together, everything has gravity, but most objects are not large enough for their gravity fields to have an effect. The earth is huge, about 5.98 x 1021 metric tons. Earth is large enough to have its own gravity field, the strength of this field is said to be 1g (one gravity) The moon too has its own mass, this is much less than earth's so its gravity field is weaker about one sixth of Earth's. The moon and Earth are pulling away from one and another, so each has an effect on the other. The moon's effects on Earth causes the tides. Earth's gravity exerts a downward force of 9.81N upon a 1kg weight, but because 9.81N is a complex number to do equations with it is rounded off to 10N so it is said that 1kg has a downwards force of 10N.

Another effect which may change the force needed to pull the block and masses along is Friction. Friction is caused by microscopic 'bumps' on the surfaces of the two objects. These 'bumps' run into each other when the two surfaces rub along each other. These collisions prevent the objects moving past each other smoothly, which means more force is required to keep the object moving at a steady speed. Also the less smooth the surfaces, the more friction will be caused meaning even more force will be needed to keep the object moving at a steady speed.

Diagram:

Conclusion:

My hypothesis was correct. As I added more weight the more force it required to pull the block of wood across the surface of the desk.

This experiment proves that the amount of friction produced increases as more mass is added which pulls the block closer to the surface making the collisions more severe and increasing the friction.

Theoretically the lines produced on the graphs should have been straight, as the weight and the amount of Newtons it took to pull the block at a steady speed are proportional. The lines on my graphs were not straight or the same and I will discuss why this is in my evaluation.

Evaluation:

There appears to have been a few problems with my experiments, as the results are not the same for the two experiments and the Newtons are not proportional to the weight, which should be the case.

With the two experiments there are a number of things that could have gone wrong to cause these slight differences:

It could be human error, small measurement errors compounding together until they become noticeable.

Lack of advanced measuring equipment may also have lead to slight measuring mistakes, which all together became noticeable.

As the experiments were carried out on separate days there was no way to guarantee the weights I received were the same. After the experiment I decided to check if the weights were all the same and I discovered that the weights did not weigh 100g, but most weighed about 97 or 98g this could also be held accountable for the errors.

Also there was no way to check that the block was travelling at exactly a steady speed so this again could have caused errors.

If I were to re-create the experiment I would attempt to correct some of these mistakes, although some would require more advanced equipment to stop them from effecting the results.

Expanding the Experiment:

To expand the experiment I could see how different surfaces, both on the block and desk would effect the Experiment.