Courseworks

An investigation to find out how different variables will effect the movement of a wooden block

Aim: Trying to find out how weight and the pull back of an elastic band will affect distance travelled on a wooden block on a particular surface.Prediction: I will predict that as the amount of mass applied onto the block, the faster the block will slow down and it will go less far. Adding on to that, I reckon if the weight applied on the block is doubled then the distance travelled will half. This is because there will be more friction between the block and the desk and there will also be more gravitational pull acting downwards on the block which will slow down the wooden block.Scientific TheoryWhen you pull back the elastic band, storage energy is made which is the potential energy of this experiment. And the more that the elastic band is pulled back or the more elastic bands used in the experiment, there will be more potential energy. After the block is released, some of the potential energy is transferred to kinetic energy when the block slides along the surface. The rest of the potential energy is transferred to heat and sound energy.Also in theory, as the weight placed on the wooden block increases, the distance travelled by the block should decrease. This is because the weights will cause a more downward force which increases the friction between the block and the surface acting against the kinetic energy, making the wooden block slow down quicker and come to a halt quicker compared to a block with less weight on. Basing on the general equation for work done, the more force that is exerted into the block, there will be more work done.W.D = F x d, work done = force x distance travelledWhich variables might be important? There are some variables which could greatly affect the outcome and the results of the experiment.* The surface of the desk that the wooden block slides on.* The numbers of elastic band used to fire the block.* The distance that the elastic band is pulled back.* The weight exerted on the wooden block.Preliminary ExperimentFor my preliminary experiment, the investigation was on the affect of different numbers of elastic bands on the total distance travelled of the wooden block. The elastic bands would be pulled back around 25cm from the front of the stool. One elastic band will be added on each stage of the experiment.Preliminary ResultsWhich Variable am I Investigating?The only variable being investigated in this experiment is weight. An investigation will take place trying to find out how weight exerted on a wooden block can affect the distance travelled of it.How am I going to make this a fair test?As with all scientific experiments, only one variable must be altered at one time. All the rest must remain constant to ensure good sensible results. By using present knowledge, I know that the following factors can affect the outcome and must be controlled and kept the same. Only the weight exerted on the block should be allowed to change, everything else, like the distance pulled back by the elastic band, the numbers of elastic bands and the surface that the block slides on must be kept exactly the same throughout the whole experiment.Apparatus* Rubber bands* Wooden block* Desk surface (wooden)* Meter rulers* A stoolSafetyThere will definitely be safety precautions to take when doing this experiment.Plan of InvestigationBased on the preliminary experiment, the investigation to find out how different amounts of elastic bands which was used to propel the wooden block affected the total distance travelled. But since there wasn’t sufficient space in the lab to undergo this experiment the investigation failed to achieve any usable results. This was because the block slid too far and recordings would’ve been inaccurate as there will be a gap between two joining tables, so the variable will be the weight in the proper investigation.To set up my actual experiment, a stool will be placed on top of the table. The rubber band which is used to propel the wooden block should be strapped between the front two legs of the stool. The wooden block will then be placed against the elastic band, in this particular type of experiment; the rubber band is going to be pulled back 25 cm. A meter ruler should also be placed along side of the surface used to measure the distance travelled by the block when it is fired.In this particular type of investigation, as mentioned above, only the weight exerted on the block should be changed, which is the only variable in the investigation. The rest of the variables, like the pull back of the elastic band and the surface of the table are going to be kept completely constant because it would affect the investigation otherwise.There is only one type of reading I will take in this and that is the total distance travelled by the wooden block. For my range, I have decided for the mass put on the wooden block to be between 0g and 700g and the pull back of the elastic band to be 25 cm. I am planning to repeat each step of the experiment three times and also noting down every result. So I could have a more even outcome which would result in a better average.There are steps to take to ensure the results will be accurate. Measurements will be made from the tip of the wooden block each and every time. The block will always be propelled from the centre of the rubber band so it would not slide to one side. Moreover, if the block spins around when it is propelled, the experiment will be restarted.ResultsElastic band pulled back (cm)Mass added (g)Results (cm)Average1232510093939192.3333333325200586365622530044444544.333333332540028343030.6666666725500212223222560017151716.3333333325700108119.666666667Below are the graphs for the three test results and the average of the three tests results, which has been done on the computer to show the precise accuracy of the numbers.Analysis of ResultsIn my prediction I said that the block would slow down quicker if more mass was applied on it.EvaluationThere were definitely some human errors and apparatus problems through put the experiment. The elastic band may have not been pulled back enough or even pulled back too much. The elastic band also may’ve stretched past its elastic limit which will cause a slight change in results. The surface of the desk is also important, as there will be graffiti marks and pen marks. But as my graph shows quite a smooth curve, meaning the errors would’ve been fairly minor.

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