In the case of an emergency:
- If burn on skin – Place under a cold tap and leave for approximately 10-15 minutes depending on the severity of the burn. Inform a member of staff immediately and seek medical attention, if necessary.
- If water is spilt on electrical equipment – Do not touch any of the equipment and immediately inform the teacher of the spillage.
- If water is spilt on the bench/floor - Don’t immediately wipe up the spillage, as the water will be hot, wait for the water to cool and then mop up the spillage with a cloth.
Also, the experiment deals with handling glass such as beakers. Glass can cause nasty and dangerous cuts to any part of the body and can also contaminate blood if the glass is unclean or contaminated with chemicals. The control measures to reduce the risks of breaking are:
- Place glass wear such as beakers away from edges of tables. Place thermometers in a book to prevent it rolling on the table.
- Wear protective eyewear in case of any breakage happening.
In the case of an emergency:
- If broken glass on floor/bench – scoop up any pieces using a dustpan and brush. Inform a member of staff about the breakage and dispose of the broken glass.
- If broken in sink – Pick up any big pieces of glass and inform a member of staff about the breakage. Again, dispose of the glass.
- If there is a broken thermometer – Inform a member of staff immediately. Remove the broken thermometer from the spillage area and dispose of it.
- If a student is hurt due to a glass breakage – Immediately inform a member of staff and seek medical advice.
REMEMBER: When conducting any experiment in the lab, you should always try and minimize the risks of any accidents happening such as taking coats and outside wear off in case of spillages/burns, placing bags under benches and tucking stools in to allow clear passage ways to be used around the classroom so no one trips and injures themselves, and clearing the desks where the experiment is being conducted in case of any spillages and accidents etc. If you are dealing with chemicals or are heating substances ALWAYS wear protective eyewear. You may also wear gloves and a protective lab coat, as they will minimise the hazards of any chemical spillages on your cloths and skin.
Preliminary Work
Preliminary work has to be done in order to determine what the final method of the experiment will be and how it is conducted. It will help decide appropriate measurements that will be needed in the final method making results reliable, sensible and accurate and appropriate testing period times which will also be needed. Different aspects of the experiment have to be tested first which are discussed below:
- Investigating the type of Ball Used
This preliminary work will help decide which type of ball is best to use for the experiment. The aim is to use a ball, which will have a higher average bounce rate as the higher it bounces, the easier it will be to record the result from the metre rule allowing less room for human error and anomalies and more accurate and precise results (as the higher it bounces, the less you or your partner has to crouch down to see where the ball bounced to on the metre rule allowing for less inaccuracies and repeats which initially saves time to ensure more experimentation can be done). Also, the higher the ball bounces, the less percentage error there is because the larger the number the less chance there is of an error for example a range of 1 or 2 at 1 metre (1-2% error) would be less significant compared to a range of 1 or 2 at 40cm (2.5-5% error). Again this ensures that the results are more accurate and of a sensible nature.
Method
- To see the difference in how high balls bounce according to the material they are made of, try to find a small range of different balls (2 or more).
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For each ball, using the tongs to hold the ball under the water, heat it to about 300C (add ice if necessary to cool the temperature).
- Set up your metre rule in a clamp (to keep it stationary whilst performing the experiment) and collect the bounce test results. For each ball, test it about 10 times to get a sufficient number of results.
- Finally when the data has been collected, arrange it into a table so that results can be compared.
To make the test fair, both balls were heated at the same temperature (so that both balls were supplied with the same heat energy), the temperature they were heated at was measured accurately with a thermometer and both balls were tested 10 times each so that the results could be fairly compared.
Results
Calculation of Average
As you can see from the results, there isn’t a huge significant difference in the bounce back height of Balls 1 and 2 and their averages are very close in value too which also implies that there wasn’t that much of a difference in their bounce back height.
Having discussed above about how I will choose a ball for the experiment, I chose Ball 1 as it has a higher average than Ball 2 which means it’s bounce back height was slightly higher than Ball 2’s bounce back height. Using this ball will enable us to get a better set of results as there will be less percentage error in the larger bounce back height figures.
- Investigating the Height at which the Ball is to be Dropped at
This preliminary testing was done in order to find out at which height the ball would give a large bounce back height and produce the fewest inaccuracies. In order to do this, a range of heights were taken from 40cm to 100cm and bounce tests were carried out 5 times each for each individual height. From the range of the results, the height will then be looked at.
Method
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Using the tongs to hold the ball under the water, heat the ball at 300C (add ice if necessary to the water to cool it).
- Set up your metre rule in a clamp (to keep it stationary when performing the experiment) and then drop the ball from the height of 30cm. Collect the data.
- Repeat this procedure five times to gain an average and range of results.
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Repeat the entire experiment again (i.e. heating the ball at 300C and then dropping it) for heights 40cm, 50cm, 60cm etc going up in 10 cm’s till you reach the height of 1 metre.
- Arrange the collected data from the experiments in a table so that they can be compared and find the average and range for the results.
To make the test fair, the ball was heated at the same temperature for each height that it was tested for (again, the temperature it was heated at was measured accurately with a thermometer), for each height it was tested at five bounce tests were conducted each so that results could be compared fairly and the height at which the ball was to be dropped was measured accurately (to the nearest centimetre) using a metre rule.
Results
Calculation of Average
Having looked at the results and discussed them with my partner, we initially thought that the best height to test from would be from the height of 70cm as it had the least inaccuracies (based on the range) and the ball seemed to produce a good bounce back height at 70cm also. But the teacher stated that the amount of inaccuracies (based on the range) was far to inconclusive and therefore would not help in deciding which height is best to test from.
So we then looked at which height produced the best bounce back height giving us less percentage error again in the larger value of height. This was, from our results, at the 1 metre height, as the average bounce back height was the highest for 1 metre. We then chose to experiment at this height and decided to incorporate it into the final method.
Ideally, heights above a metre would have proven to give us better results with even larger bounce back heights of the ball but because we were limited to perform the test on a bench surface, any height above a meter would prove to be too difficult to carry out as a ladder or other such device would be needed to help drop the ball from the height and this was not practical in the lab.
- Investigating the Time to Heat the Ball
This final preliminary experiment was conducted in order to find out at which time the bounce back height became constant so that it could be heated for this amount of time and then be tested at different temperatures.
The ball would be heated for a range of different times and its bounce back height was observed until it seemed to become constant.
Method
- Using tongs to hold the ball under the water, heat the ball in a water bath (glass beaker full of warm water) to 300C (add ice of necessary to cool down the temperature of the water) for 15 seconds.
- Set up the metre rule in a clamp (to hold it stationary while you perform the experiment) and hold the ball exactly 1 metre above a hard surface (i.e. desk top) and then drop the ball. Ask your partner to measure where the ball bounced up to.
- Repeat this bounce test for the heated up ball three times to gain an average result and record the results in a table.
- Then re –warm the ball in the water bath to 300C for 30 seconds (using the help of tongs to keep the ball under water and adding ice of necessary to cool the temperature of the water).
- Again, hold the ball exactly 1 metre above a hard surface and then drop the ball. Ask you partner to measure where it bounced up to.
- Re- drop the heated ball three times to gain an average result and record the results in a table.
- Continue on as above, increasing the time you heat the ball by 15 seconds each time until the height of the bounce seems constant.
To make the test fair, we kept the temperature of the water at a constant of 300C for each time we held the ball under water (so that each time the ball was supplied with the same amount of heat energy) and the ball was dropped from exactly a metre high each time (measured using a metre rule to the nearest centimetre).
Results
Calculation of Average
From the results, it is evident that at 60 seconds the height of the balls bounce remains constant after the ball has been heated. Therefore, 60 seconds seems to be the ideal time for the ball to be heated up for before it is tested out at different temperatures. It seems that after 60 seconds the ball is completely heated up. It noticeable that after the first drop there is a fall in bounce back height. This could be because as the experiment was conducted, the ball cooled down as it lost the heat it had from being warmed up in the water bath.
Final Method
Having conducted the preliminary tests, I’ve established certain measurements which will suitable to use in the final method to get a good set of result such as the time the ball will be heated for before it is tested at different temperatures, the height at which it should be dropped to obtain good results and finally, which type of ball to use. These will all be incorporated in my final method as shown below:
- Collect the required equipment (mentioned in the apparatus section).
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Fill a large beaker half way up with hot water and using a thermometer make sure it’s at 850C.
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Using tongs to hold the ball under water, heat the ball in the beaker full of water at 850C (add ice if necessary to cool down then temperature of the water) for 60 seconds.
- While the ball is being heated, set up your 1 metre rule on a hard surface and clamp it so that it will remain stationary when you perform the bounce test.
- Once the ball has been heated, hold it exactly 1 metre above the hard surface and then drop the ball. Ask you partner to measure where the ball bounced up to.
- Repeat this five times for the same temperature to gain an average height.
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Repeat the experiment again but lower the temperature by 50C. Keep doing this until you reach 200C. Then take a final result at 100C.
- Collect the data from your experiment and arrange it into a results table.
(See diagram on next page)
Fair Testing and Variables
Testing has to be done fairly in order to achieve accurate and reliable evidence, which a correct and scientifically sound conclusion can be made from. A number of factors, which could affect the height of the bounce of the ball, are:
- Type of Surface
- Angle of Surface
- Angle at which Ball is Dropped
- Material of Ball
- Mass of Ball
- Diameter of Ball
- Temperature of Ball
- Pressure of Air in Ball
- Air Resistance
- Height of Drop
- Force used to Drop Ball
- Acceleration Due to Gravity
To make the test fair, certain variables have to be kept fixed and at a constant otherwise the results would not be right and a conclusion cannot be drawn from the anomalous results.
Basically, all the variables listed are to be kept at a constant apart from the temperature, as this is the variable I am investigating. Additional issues to take into account to produce fair testing are that the same equipment is used throughout the experiment i.e. the same surface (reasons about why is discussed above), same metre rule etc. Also one person will be appointed to read off values from the metre for the bounce back height of the ball as different people will approximate the height values differently making the results slightly anomalous.
My fixed variables, which will ensure that testing is fair and results are accurate and reliable, are:
According to how much force is applied to drop the ball, it will bounce higher or less. If suitable equipment was available in the school, students may be able to automate the “dropping of the ball” process so that a machine drops it from a given height. This would eliminate the possibility of human error, as we would not be able to drop the ball with an equal force each time making the results unfair. However, such equipment is not available to use and so the next best thing to do is to simply hold the ball at whichever height you wish to test it at and then let go of the ball, applying no force and letting gravity pull the ball down to the hard surface. This will be done to all the balls when dropping them to ensure fair results.
- Acceleration due to Gravity
The gravitational pull is lower in areas of high altitude, so if the experiments were carried out at different altitudes, the results would be unfair as there is less gravitational force acting on the ball. However this is very unlikely to happen, as all tests will be carried out in the lab, at a constant altitude making the tests fair and the results reliable!
As seen in the preliminary work, the higher the height at which the ball is dropped from, the higher it will bounce back. This is because as the ball travels down, it has more time to gather speed if dropped from a higher height due to the acceleration of gravity and this will increase the height at which the ball bounces back up as the ball will bounce up with a greater force. For all experimenting, the height will be kept at a constant i.e. if I was investigating the bounce of ball heated at 300C I would test each bounce at the same height to ensure the result is fair.
This variable affects the bounce of a ball in a number of ways:
- According to what material it is made of, its molecules may melt and reduce the height of the bounce earlier or later than other balls.
- Some materials may be better insulators of heat which would mean that they would bounce higher than those balls made of materials which are poor insulators as they will not loose the heat energy as quickly.
- Some materials may have a molecular structure that allows a lot of space for air molecules which would result in an increase of air pressure within the ball affecting its bounce back height (the higher the air pressure, the higher the bounce back height).
To have fairness in the testing of balls, I will use the same ball each time for any kind of testing ensuring that the material of the ball is not different giving accurate, reliable results. To be very fair, a different ball made of the same material should be used each time as using the same ball which has been heated several times may affect the results slightly.
The heavier an object is, the faster it’s acceleration rate. This can be shown using the equation F=ma where m is the mass of the object and a is the acceleration rate. To understand why the mass of an object affects the acceleration rate, when we rearrange the formula to make a (acceleration) the subject, we get a=F/m, force divided by mass gives acceleration. Because F is constant, this means that the bigger m is (or the mass) of an object, the bigger the acceleration is. Knowing that the mass of the ball will affect the results, I will be using the same ball (of the same mass) to ensure that its acceleration rate will be constant throughout the experiment.
A larger ball with a larger diameter will have a bigger surface area meaning that when it hits the floor, more of its area will be in contact with floor at impact and this will affect it’s bounce back height. For this reason, to make the test fair, the same sized ball with the same diameter will be used.
Different surfaces have different smoothness and changing the surface half way during the experiment will make the test unfair as some surfaces according to their smoothness will allow a nice, neat bounce whereas other surfaces will alter the bounce due to indentation in the surface and bumps etc. To make the test fair, all testing will be done on a bench surface throughout the experimenting procedure.
The angle of the surface at which the ball is bounced on will affect how it bounces back up and how far too. To overcome this, a surface, which is horizontally straight, will be chosen to experiment on. This same surface will then be used so that there will not be any change in its angle making the test fair.
- Angle which Ball is Dropped at
Changing the angle at which the ball is dropped half way through the experiment would make the results unfair again as it would affect how the ball bounces back up (at what height). For my experimenting, I will simply drop the ball perpendicular to the hard surface each time ensuring that this is the angle at which it is always dropped throughout the experiment.
As the squash ball moves through the air, the air in front of it experiences a rise in air pressure and pushes the ball in the direction opposite its motion. While there are various other changes in air pressure around the ball's surface, this rising pressure in front of the ball remains largely unbalanced and it slows the ball down. The higher the air pressure was to start with, the greater its rise in front of the ball and the stronger the backward push of air resistance. Because the experiment will be conducted in the same room (where the air pressure is the same) the testing should be fair as the air resistance will also be the same.
Different balls will be able to hold different capacities of air and so using one ball will ensure that its air capacity is the same throughout the experiment. If the amount of air in the ball was to be changed, when heating the ball, if there is more air then the pressure of the ball will increase (as more particles collide in the ball faster and faster as they are supplied with extra energy from the heat) thus increasing the height at which it bounces back up at. Balls with more air capacity will bounce higher than those will less air capacity. Therefore, to keep the testing fair, the same ball will be used to ensure it has the same air capacity all throughout the testing.
Results
To ensure that a wide range of results would be taken so that a good conclusion can be formed from them, we chose to take 15 different readings of temperatures and tested the squash ball at each temperature five times. This thorough approach will help give a good range of results and with the variables being kept all constant apart from temperature; the results produced will be fair, accurate and reliable.
(See graph on next page)
Calculation of Averages
Analysis of Results
Looking at the graph it is clear that as the temperature is increased, the bounce of the ball also increases proving the first part of my prediction to be right. This can be supported the Kinetic Theory as it deals with molecules vibrating and breaking their bonds as they receive more energy. When the ball is heated, the heat energy given to the ball will affect the air molecules inside it, giving them more energy to collide and move faster and faster. This would result in more collisions of the air particles with the particles of the ball thus increasing the ball’s overall air pressure. With this increase of air pressure within the ball, the ball will deform less when it comes into contact with the floor than it would when it has a lower air pressure because constant, rapid collisions of the air molecules inside the ball help maintain the shape of the ball better at this higher pressure. Due to the ball deforming (or flattening) less, it loses less sound and heat energy and therefore has more energy to be used in motion resulting in the ball bouncing higher.
However you would think (by seeing the straight line of the graph) that the relationship between the temperature and the height of the ball is proportional as it begins with a straight line. If this were the case, part of my prediction would be wrong, as it would mean that as the temperature is doubled, the height of the ball is also proportionally doubled.
Nevertheless when looking at the actual points of the graph in relation to the line of best fit, it is quite evident that the effect of doubling the temperature does not make the ball bounce proportionally or more than double, it in fact less than doubles. To support this, look at the temperature 200C. Its bounce back height is about 21 cm (if read off the line of best fit, it’s bounce back height should be about 19 cm) and the bounce back height for 400C is about 29 cm (again, reading off the line of best fit, it should be about 31 cm). As you can see, even though the temperature is doubled, the bounce back height is not doubled (if it was doubled, then at 400C the point should have been on 38 cm but even the point on the line of best fit shows that according to my results it should be on about 31 cm which is a lot less).
On the sketch made in the “prediction” section, I drew a steep curve, as I believed that the gradient would be far bigger as the ball will bounce back more than double when the temperature is doubled. But the calculated gradient on the graph also supports the fact the ball bounce less than doubles when the temperature is doubled, as it is a far smaller value. This is happening because the energy lost as the ball hits the surface is far larger than I initially thought it to be effecting the bounce back height of the ball, making it bounce back less than double due to the significant energy loss. It seems that far more energy than initially expected is lost through heat and sound when in contact with the hard surface and the heat energy that the ball is provided with when it is being warmed in the water bath does not account for and outweigh the energy lost as originally thought, it merely balanced out the energy lost producing the straight line on the graph. It could depend on what type of material the ball is made out of, rubber polymers are more loosely arranged and rub together more when the ball deforms after it has been dropped. This additional movement results in motion being converted to heat energy; instead of the ball bouncing, it gets warmer resulting in a smaller bounce back as less energy is left to use as motion.
Further up on the graph, the straight line develops into a small curve, as predicted in the graph sketch made earlier in the “prediction” section. This is because, as stated in the prediction, after a certain temperature, the molecules of the ball will begin to melt and deform in shape, reducing the overall bounce of the ball making the curve less steep as its gradient is decreased. My prediction stating that the kinetic theory may help explain this is correct. As the atoms get more and more energy in the form of heat, they speed up moving faster and faster in the ball. After an excessive amount of heat, in our case, about 650C, the bonds between atoms break and this causes the “melting” effect of the ball. Because the molecules are beginning to melt, when the ball is bounced, it no longer bounces back as well as when the molecules were not melted and thus we see the smoothening out of the curve on the graph as the gradient is decreased.
Towards the very end of the graph (after the 850C point) the atoms of the ball are rapidly melting resulting in an almost straight line on the graph. Because of the melting of atoms in the ball, the height of the bounce back is affected as when the ball is bounced, its surface is no longer solid and does not hit the surface but almost sticks to it resulting in a much lower bounce.
Also, my sketch of the graph showing the line not going through the origin is also correct. As you can see on the actual graph, if the line of best fit clearly doesn’t go through the origin of the graph (0,0 point) because there is still some molecular activity happening at 00C. If the graph was extended backwards, as suggested before, we may be able to see at which point no molecular activity is taking place. But because the graph would have to be extended backwards, it suggests to me that the temperature at which molecular activity stops would be at a negative value (below freezing).
From the analysis of the results we can conclude that most of my prediction was correct and:
- The balls bounce does increase as the temperature increases. This is explained by the Kinetic Theory (discussed in detail above).
- That I was wrong in thinking that the effect of doubling the temperature would more than double the bounce of the ball. In fact, when the temperature doubles the bounce less than doubles due to significant energy loss through heat and sound as the ball hits the surface. Originally, I thought the heat energy given to the ball whilst heating it in the water bath will compensates for this energy resulting in a more than double bounce but as seen by the graph it merely balanced out the energy lost producing the straight line on the graph.
- At higher temperatures the ball does in fact stop bouncing as high due to excessive heat melting the atoms of the ball (as more and more energy is given to them to break their bonds), resulting in a curve on the graph proving this part of my prediction to be correct.
- The graph line did not begin or go through the origin, as there is still molecular activity happening. Only if we look at negative temperature values will we be able to see exactly where the molecular activity stops (or begins).
Evaluation
I will be evaluating the evidence obtained from my experimenting in four ways, which will cover if the results were accurate, reliable, and how they could be made more precise by altering the method in certain ways. The three aspects that I will be evaluating are Quality of Evidence, Reliability of Evidence (here the suitability of the procedure will also be discussed), and Further Work and Improvements.
The quality of the evidence seems to be very good as the graph produced showed that nearly all points plotted followed the positive trend shown by the line of best fit concluding that my prediction stating that the higher the temperature of the ball, the bigger it’s bounce. Also, the points were situated fairly near the line best fit (showing that the results were of a high quality and accuracy as the line of best fit shows where the points should have been had the experiment been immaculately perfect).
In our method, we made sure that results would be of a high quality and accuracy by testing the ball’s bounce at each temperature five times so that an average can be gained minimizing the chance of any anomalies. This made the quality of the results better as the range of the repeats was 1,2 or 3, which is very precise for our results that we had obtained from our method.
Of course, because the procedure was done in a classroom by humans and wasn’t automated by a machine, some results were plotted a bit further away from the line of best fit; however, these are not anomalies but are merely less accurate results as they are not situated ridiculously far away from the line of best fit such as the points at the temperatures 250C and 300C, which were situated more above the line than most points and the points at 400C, 450C and 500C, which were situated more under the line than most points. If these points were more accurate, the distance between the line of best fit and the point would have been less than it is on the graph.
The only point, which is an anomaly, is that at the temperature of 650C. It didn’t follow the trend as well as the other points as it was situated a significantly large distance away from the line of best fit in comparison to other points implying to me that there was some sort of fault whilst conducted the experiment at this temperature. Had it been an accurate result, it should have been plotted nearer to the line of best fit at the height of about 46-48cm. This was the only result that produced a range of 3 in comparison to other results that had a range of mostly 1’s or 2’s.
So overall, we can conclude that the results were very accurate considering the process wasn’t automated and therefore did not reduce the chance of human error as nearly all points expect one followed the positive trend of the graph and were nicely situated near the line of best fit showing they were accurate and precise.
Here I can discuss why there was an anomalous result at 650C and how it could have been made. As discussed in the “fair testing and variables” section, every effort was made to make the testing of the ball fair by testing the same ball made of the same material (using the same ball ensured that the amount of air in it was the same so air pressure was not affected, it’s diameter would be kept the same and also its mass), testing on the same surface, dropping the ball at the same height, testing in the same lab (so that air resistance and altitude was the same), making sure the angle of the surface tested on was kept at the same angle, dropping the ball at the same angle and finally, letting go of the ball rather than using force to drop it each time. Keeping these variables as accurate and as constant as possible did make the results reliable and precise as seen on the graph and it ensured that the results were fair overall. However, the anomaly at 650C could have been caused by:
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The temperature of the water. Keeping the temperature constant proved to be difficult as it kept dropping rapidly. This may have affected how much heat energy the ball received, affecting its bounce according to whether it received less or more heat energy than it should have. For the anomaly at 650C, the ball may have been heated up more than 650C as it’s average bounce back height was higher than the other results around it (for example at 600C, the average bounce back height was 45cm and at 700C the average bounce back height was 49cm so ideally, had the anomaly been a “normal” result, the bounce back height for 650C should have been in between 45cm and 49cm and not 50cm) proving it to be situated further away from the line of best fit.
- Increase in room temperature. Because the lab was occupied with many students carrying out a similar experiment with hot water, the room got warmer. This could affect the air molecules in the room, which could also possibly affect the speed of the ball as it is dropped due to the change in air resistance.
- Inaccurate reading of the height. Even though a metre rule was used to ensure the height could be measured to the nearest centimetre, when the ball was bounced, it bounced back very fast and reading the height at which it bounced back proved to be difficult. All efforts were made to ensure that the reading was a close to the bounce back height as possible. But again, the procedure would have been far more reliable had it been automated and the value at which the ball bounced back was read by a machine to get an accurate result.
- The height at which the ball is dropped. Even though a metre rule was used, holding the ball exactly at a metre was difficult as the metre rule was set up on the bench and we could just barely reach above the metre point. Some drops of the ball may have been done at a distance slightly less than a metre affecting the bounce back height of the ball.
- The surface on which the ball was tested. Ideally, we would have liked to have as smooth surface as possible to test the ball on making sure that no indentations or dips (changing the angle of the surface), affected the ball’s bounce but because we were using a bench surface which had been used many times before to conduct different experiments, there would inevitably be scratches and other such distortions on the surface, which may have affected the bounce back height of the ball.
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Mass of the ball. Because the ball was heated in water, the water droplets left on the ball may have changed the mass of the ball resulting in a difference in it’s acceleration speed as it was dropped (more mass = higher acceleration rate). This could explain why the ball bounced higher at 650C because if it accelerated more, its bounce back height will have been higher.
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Force given to the ball when dropped. Even though we tried our utmost best to merely drop the ball from the metre distance, some drops may have had more force applied to them than others resulting in the ball bouncing back higher. This could again, explain why the ball bounced higher than expected at 650C.
Apart from this one anomaly, results were overall very reliable. The points which were not quite as near the line of best fit as expected could also have been effected by the same aspects discussed above such as keeping the temperature constant and the difficulty in reading off the bounce back height etc.
The reason as to why most of the results are reliable is that wide ranges of results were obtained in total, 15 different temperatures were tested and each was tested 5 times. This highly reduced the chance of inaccurate results as a good average was obtained and by looking at this wide range of temperatures, a complete trend was visible rather than a small part of the trend, which could have been misleading and lead to a wrong conclusion. For example, as discussed in the analysis, if we had only tested between 100C and 600C, a straight-line trend between the temperature and the bounce back height would have been seen which could have suggested that the relationship is proportional when in fact it isn’t. From these wide ranges of results a good conclusion was made, as the complete trend is visible.
- Further Work and Improvements
The anomaly was evidence that the whole procedure could have been improved to produce better results. As mentioned before, if the whole procedure was automated so that a machine would drop the ball at exactly a metre, would apply the same force when dropping the ball and would measure exactly where the ball bounced back up to using a laser or a similar device then the results would have been far more accurate and reliable as the aspect of human error could then be eliminated.
Also, if an electrical water bath was used, keeping the temperature of the water would have been far easier and would again eliminate the possibility of human error, as the water bath would accurately heat the water to the right temperature. It would also keep the temperature constant ensuring that the ball receives exactly the amount of heat required for its bounce test.
If enough balls of the same type were available, it would have been better to use a different ball for each temperature that needed experimenting on so that the same ball would not get overheated by re-heating it constantly at different temperatures affecting its bounce back height.
Also, if an immaculately smooth surface was used, it would decrease the chance of any anomalies, as it would ensure that the ball bounced onto the surface at the same angle, giving more accurate and reliable results.
Basically if the equipment could have been more advanced such as the electronic water bath, lasers to measure heights, machines to drop the ball with the same force, electronic thermometers that read off values accurately etc, the results would have been far more accurate and the chance of producing anomalous results decreased substantially.
Further work that could be done to investigate deeper into the experiment is to see at exactly which temperature the molecular activity ceases. This would have to be done by automation as at negative temperatures the ball wouldn’t bounce very high and therefore to measure the height it bounces at would have to be measured using a laser. You could try increasing the range of temperatures so that you are experimenting every 10C so that a clear, gradual change in bounce height (and therefore molecular activity) can be seen to prove that even at 00C there is still molecular activity happening and that the exact temperature at which it stops can also be observed with this higher range of temperatures that are investigated. Again, a number of repeats can be done to gain an average and better, more accurate results.
Investigation could be done as to how much the pressure of the ball increases as the temperature increases. Does the relationship with the bounce of the ball and the height match the relationship with the pressure and the temperature? The results could be plotted and then analysed to see what the trend is and how it compares with that of the balls bounce and the temperature.
Because this experiment involves a variety of variables, they could all in turn be tested, i.e. what is the effect of different sized balls being heated up at the same temperature and then being bounced? At what angle would a surface have to be to affect the height of the bounce significantly and does heating the ball before changing the angle of the surface affect how it bounces off the surface? A higher height could be tested, so instead of dropping the ball at 1 metre, you could drop it at 1.5 metres etc and see the effect of the bounce. Different surfaces could be investigated to see just how much they alter the bounce of the ball.
Balls of different materials could be heated and then tested to see how their material affects their bounce height. Endless other such experiments could be conducted at different altitudes, in areas of different atmospheric pressure etc.