Electricity and Magnetism - Sample Essay
Investigation: To See if the temperature of a squash ball and the height it is dropped from affects the height of the bounce and amount of energy used up. Choice of Equipment: I have chosen to use a video camera to measure the bounce of the squash ball. A Meter ruler to measure the height the ball is to be dropped from and the height of the bounce. A heat proof mat, tripod stand, a beaker, a Bunsen burner and a thermometer to use as a water bath to heat the squash balls to set temperatures. I also need a clamp stand to hold the ruler vertical to improve the accuracy of my measurements.
Precision scales to measure the mass of squash ball accurately. I will also need a constant surface to drop the ball onto to make the results fair. This is because if one time the ball drops onto a groove or a uneven surface more energy cud be wasted and the results wouldn’t be fair. Preliminary Work: As I know from previous work that, potential energy lost is equal to kinetic energy gained I am able to measure the energy loss after the squash ball has bounced from varying heights and changing temperatures (of the ball).
I can do this by measuring the potential energy the ball has at the height it is to be dropped from found by Mass x Gravity x height and then measure the amount of energy it has at the height it bounces to also found in the same way. I can look at this for different heights and temperatures, allowing me to see if temperature and height effects energy loss. I have decided to use two variables temperature and height I will adjust both one at a time. 30 – 50 degrees will be the range for temperature and there will be intervals of 5 degrees meaning 5 different temperatures (as I found anything over 50 degrees may be dangerous to handle).
The Range For height will be 60cm – 1m in intervals of 10cm meaning 5 different heights. I found this range appropriate as I found if I dropped it from a smaller height the bounce would be too small to measure accurately and these heights gave the easiest and most reliable bounces to measure. I will repeat each reading 3 times. This will allow me to take an average to improve the reliability of my results. Also from previous work I know that the higher an object is above the ground the more potential energy it has.
This means the higher The ball is dropped from the higher it should bounce, as most of the potential energy it has is converted to kinetic energy as it falls “Assuming that no energy is lost in the process the decrease in gravitational potential energy equals the gain in kinetic energy”. This means the higher the ball is dropped from the more kinetic energy it has when it reaches the ground, and if the ball has more kinetic energy as it bounces there is more to convert to potential energy so the higher the ball bounces. This should show that the higher the ball is dropped from the higher it should bounce.
I also know that as temperature increases, the molecules in the ball gain more energy and begin to move more, as the molecule vibrate more and as rubber has a positive temperature coefficient the ball has more energy the hotter it becomes. This increase in energy should increase the height that the ball bounces as it will have more energy in total as it initially reaches the ground than a cooler ball would. Method: 1) – Collect equipment listed above and set up appropriately making sure ruler is perpendicular to the horizontal surface the ball is to be dropped on to, by using a set square and level.
2) – Weigh the squash ball 3 times on the scales and take an average of the masses. This mass will then be used as the mass of the squash ball. 3) – Place the squash ball in the Water bath and heat to the desired temperature (30 then 35 then 40 then 45 then 50 degrees). 4) – While waiting for the ball to reach the temperature desired, work out the amount of Gravitational potential energy the ball as at each set height and record them in a table. This is found by Average mass x height to be dropped from (50,60,70,80,90 and 100 cm) x 9. 81 (gravity).
5) – Set the video camera up so that it can see the area where the balls are to bounce and press record. 6) – When the ball has reached its desired temperature remove it from the water bath and Drop it from each height. 7) Replay the video camera and record the results to where the top of the ball bounces to, then work out the potential energy of the ball at the point it bounced to. This is done by Average Mass x Height Ball Bounced to x 9. 81(gravity) 8) Work out the energy loss 9) Repeat steps 3 – 8 two more times and record all results in a table. 10) Take an average of all the repeated steps and record in the same table.
11) (errors) 12) Plot graphs of the results To ensure accuracy and precision of my results I will use fiscal marks in order to help me measure bounce more accurately. They will be placed at 10,15, 20,25 and 30 cm as I found the squash ball would not bounce much higher than this. I will also use a constant surface as if the ball bounces onto a rough surface more energy could be used on one bounce compared to another, this should improve the accuracy of my results. I am also aware of measurement errors, which can occur, and this is why I have set a margin of error on each reading.
This will be + or – 2mm when measuring bounce. By measuring in mm I will be able to calculate more accurately the energy loss. It will be + or – the Average Mass x 0. 2(cm) x 9. 81 (gravity). Safety To ensure the safety of everyone around I will firstly work in a clear area. I will also be vigilant and watch the experiment to make sure nothing is going wrong. As my experiment involves fire I will keep all flammable things away from my experiment and will also use tongues or tweezers to pick the squash ball out of the heated water to avoid burning my hands.
Finally I will remove all obstacles around my experiment such as chairs and bags to avoid people tripping up and accidentally injuring themselves.
Bibliography Teachers – Mrs Karadia/Mr Heath Textbooks – A level physics (Roger Muncaster) Physics One Websites – squash association website Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Electricity and Magnetism section.