What factors affect the distance traveled by a margarine tub?

GCSE Science

PLAN

Aim: To find out what factors affect the distance traveled by the margarine tub.

From previous research, I’m aware that there are other factors that affect the distance traveled by the margarine tub.

Variables:

Friction – If the tub has no force propelling it along it will always slow down and stop because of friction. To travel at a steady speed, the tub will need a driving force to counteract the friction. As friction increases, the speed increases. It converts potential to kinetic energy and wastes it as heat energy. There are things that will affect the amount of friction that occurs. One of them is the weight that presses the two surfaces together, and that friction is proportional to this load or weight that presses the surfaces together. The surface area of the object does not affect friction because the total area of contact at these points is small compared to the total surface area of the object. If the weight of the object increases, the pressure at the contact points also increases and the surfaces are pushed together. This leads to an increase in the friction force between them. I know from textbooks and from lessons that friction will affect how far certain object travel. Since I'm not going to change the friction or not going to change where I will do my experiment I don't need to worry about this factor.

Force – The force will affect the distance traveled because the greater the force, the greater the friction. As a result of increasing the force the speed will increase and the distance will be greater. The greater the force, the greater the acceleration. Any resultant force will result in acceleration and therefore this is the formula:

F=ma (Force = Mass x Acceleration)

This is showing the relationship between the force and the acceleration.

Mass – Mass is the amount of matter in an object. In our case it’s the amount of matter in the margarine tub. The greater the mass, the speed will decrease and the friction will increase. Also the bigger the smaller the acceleration. The friction acting on the tub will decrease as well. Therefore the mass has an effect on the acceleration and it can be shown using this formula:

a=F/m (Acceleration = Force/Mass)

For this investigation I am going to find out how changing the mass of the margarine tub affects the distance in which it is projected.

PREDICTION

This is a preview of the whole essay

a=F/m (Acceleration = Force/Mass)

For this investigation I am going to find out how changing the mass of the margarine tub affects the distance in which it is projected.

PREDICTION

I predict the greater the masses of the margarine tub, the shorter the distance it will travel. This is because as the mass increases, the frictional force is greater. This means that there is a greater pressure between the tub and the floor. The higher the pressure is the greater the amount of heat produced due to friction. This heat is lost quickly and so the tub travels a shorter distance. Whenever energy is transferred a force moves. Because the force is the same all the way through, the acceleration is going to decrease. This is due to the formula found in my research: a = F/m Therefore the tub will cover less distance each time. As the elastic potential energy is converted to kinetic energy that is converted further into heat energy. I predict that this should produce a smooth, curve on my graph, as this will show that as the mass increases, the distance travelled will decrease.

METHOD

Apparatus List

Newton Meter
10g weights
100g weights
Margarine Tub
Stool
Sellotape
Paper Strips
Elastic Strip
Meter Sticks
Ruler

PRELIMINARY WORK

First we did 2 preliminary tests to find out which force to use and to find out a suitable range of weights to use. For the first test we varied the weights to decide which weights to use. We did as follows:

Get an elastic strip and attach it to the bottom of the stool.
Put 10g in the margarine tub and fix the tub in front of the strip.
Get the Newton meter and hook it to the elastic and pull back until it is 5N.
Measure the distance.
Repeat each step until you have 4 readings of each weight. Repeat them for 50g, 100g, and 200g. Make sure you keep the force at 5N

For the second preliminary test we varied the force to decide which force to use. We did as follows:

Get an elastic strip and attach it to the bottom of the stool.
Put 10g in the margarine tub and fix the tub in front of the strip.
Get the Newton meter and hook it to the elastic and pull back until it is 2N.
Measure the distance.
Repeat each step until you have 4 readings of each force. Repeat for 4N, 6N, 8N, 10N. Make sure you keep the weight at 10g.

From my preliminary work, I found that the best force to use is 6N because it travels better than the rest. I will change the mass as a variable (0g, 20g, 40g, 60g, 80g and 100g). For the experiment I will keep the force the same at 6N and use weights ranging from 0g to 100g, going up every 20g. I will also repeat the test to get 4 readings for each weight and then get an average to make the experiment fair.

METHOD

After a preliminary run was carried out to find a suitable range of masses to use for this experiment, the following range was decided for the different masses: 0g - 100g in 20g masses (without including the weight of the tub). The experiment will be repeated at least 4 times to ensure accurate and reliable results. I am going to measure the distance travelled (meters) by the margarine tub, which contains various masses (g).

For our actual test we decided to use 6N and use weights from 0g for our control and go up in 20g until 100g. We did as follows:

Get an elastic strip and attach it to the bottom of the stool.
Don’t put any weights in for the first one but keep the force at 6N (Control). Fix the margarine tub in front of the strip.
Get the Newton meter, hook it to the elastic then pull back until it is 6N and then you release the Newton meter (the margarine tub should go).
Measure the distance.
Repeat the last 4 steps until you have four readings for each weight. Repeat for 20g, 40g, 60g, 80g and 100g. Make sure you keep the force at 6N.

RESULTS

GRAPH ON NEXT PAGE

CONCLUSION

From looking at the graph I can see that the graph is negative as it is going down. From the graph, I can also see a pattern. It’s telling me that as the mass increases then the average distance traveled goes down. The graph shows that the more mass there is in the tub, the less it travels. I have some anomalous results, which could be due to a number of reasons:

The stool sometimes moves.

Sometimes fingers can get in the way when the margarine tub is being projected.
The distance travelled by the margarine tub may not have always been measured accurately.

The line of best-fit shows that as the mass is doubled then the distance travelled by the margarine tub has decreased by nearly a half. This is because as the masses in the tub are increased, the friction/pressure between the floor and the tub also increases. This then creates an increase in heat due to friction, which is quickly lost and so causes the tub to travel a shorter distance. Also, if the force and the pull back distance remain constant and the mass is doubled, the distance travelled is nearly halved because the elastic potential energy is converted to kinetic energy, which is then converted to heat energy. A smooth curve can be seen on the graph, which is what I earlier predicted. A smooth curve can be seen because the graph shows that the more masses put into the tub, the less the margarine tub travels. Some of the frictional energy may also have been lost through sound and air resistance, as well as heat. Looking at the graph, I can also see that as the mass becomes even greater, there will be no distance at all covered. This now takes me back to my prediction. My prediction and research state that as the mass increases, then the distance the tub travels will decrease. The amount of friction acting on the tub as well increased. It tells me that if a big mass were to accelerate as fast as a small mass, it will need a bigger force. It’s like pushing a trolley, it has a bigger mass but yet the more force you put on it, the faster it goes. I also said that the acceleration would decrease as a result of the constant force. It is also affected by the mass and it can be shown by this formula: a = f/m. This confirms my prediction and tells me that it is right.

EVALUATION

I thought the experiment went fairly well. We got some accurate results but then again not entirely. My original plan did not change and I think that the method was good enough to produce results, but to make the experiment more accurate, the same people did the same job throughout, the tub was pulled back the same amount each time and the same equipment was used. Some of the results were not as accurate as they could have been. The way to improve this is by making sure the measurements are accurate by actually looking properly. If the experiment was to be repeated, I would not use just stools as we found out that they kept slipping because they were too light. Therefore, I would suggest using stools again but have a person sitting on each stool to make sure it wouldn't move. If this was to be done, you would have to make sure that the people who were sitting on the stool are of similar weights too make sure it remains a fair test. I think also sellotape should have been used to tape the weights down inside the tub as if the masses are loose, the masses may help the margarine tub by hitting the opposite end making it move further. Also the tub we used affected our results as well because it was quite rectangular and oval like and so the air resistance around the tub will be different. If we used a round tub the air resistance will be the same and so the speed will be different. The anomaly on the graph could have been due to the fact that the stool sometimes moved and fingers got in the way of the tub when it was projected. The tub also sometimes flipped over when released. To improve this in future, if the tub flips over or fingers affect it or the stool moves, I won’t count it and I will repeat that particular reading.