# The size of the ball Safety - Sample Essay

What Factors affect the height of the bounce of a ball? Aim: My aim is to determine how one factor that I control can affect the height of the bounce of the ball. Background Information: Before a ball is released, it is stored with gravitational potential energy, which is energy dues to height. It can be calculated with the formula: Potential Energy = mass ( g ( height (Where g stands for gravitational field strength, on earth it has the value of g = 10m/si?? ). As the ball is dropped the speed of the ball increases and the gravitational potential energy is converted in to kinetic energy, which is energy of movement.

It can be calculated with the formula: Kinetic energy = 1/2 ( mass ( velocityi??. When the ball hits the ground it begins to slow down and has no gravitational potential energy but it also starts to deform. But if there are no energy losses the total energy, potential energy and kinetic energy stays constant. The kinetic energy in the ball is used to deform the ball. Some of the energy is stored as elastic potential energy in the ball and some of the energy is converted into heat and sound.

When a ball reaches zero speed and maximum deformation, it has no kinetic energy and as some of the energy has been converted into heat and sound, it’s elastic potential energy is less than its initial gravitational potential energy. The total energy, potential energy, heat and sound stays constant. When the ball returns to its original shape, some of the energy that was stored as elastic potential energy is converted back into kinetic energy, heat and sound, this is when the ball starts to bounce therefore I predict that as I increase the height of which the ball is dropped at, the height of the bounce of the ball will also increase.

The reason I predict this is because I know that as you increase the height of the ball dropped, the ball has more gravitational potential energy stored within it. So as this happens, the amount of potential energy converted into kinetic energy has also increased. As the ball bounces back after touching the floor, there is a greater amount of kinetic energy being converted back into potential energy, so as this happens the height of the bounce will be also higher. Hypothesis: From my prediction, the reason I believe that if a ball is dropped at a higher height, then the height of bounce will be also higher.

This is because I know as you increase the height of a ball; the amount of gravitational energy stored within will increase. I know this because the formula for working the potential energy is: POTENTIAL ENERGY = MASS ( GRAVITATIONAL FIELD STRENGTH ( HEIGHT You can see from the formula, that the potential energy will increase if height increases. Also as the height increases the kinetic energy will also increase, this is because at a higher height, the velocity of the ball will also increase, we know by the formula that as velocity is increased so does the amount of kinetic energy:

KINETIC ENERGY = 1/2 ( MASS ( VELOCITYi?? The amount of potential energy being converted into kinetic energy is greater while the ball is falling down. When the ball hits the ground it has no potential energy, the kinetic energy of the ball is being used to deform the ball. When the ball reaches maximum deformation, it has no kinetic energy but some energy has been stored as elastic potential energy in the deformed ball. Also when the ball hits the ground, it gives out sound energy and also gives out heat energy because of friction against the ball and surface.

As some energy has been converted in to heat and sound, it’s elastic potential energy will be less than its initial gravitational potential energy. When the ball is returned to its original shape, the energy that has been stored as elastic potential energy is converted back into kinetic energy, heat and sound energy, this is when the ball starts to bounce. But as there was a greater amount of gravitational potential energy due to the height, the amount of elastic potential energy stored in the ball would also be greater.

So when the greater amount of elastic potential energy is converted back into kinetic energy, heat and sound energy will also be greater, so the height of the bounce will also be higher. But because some of its initial energy is converted into heat and sound energy, it will finish up with less gravitational potential energy then what it started of with, so the height of the bounce of a ball will be less than the starting height.

Key Variables: The variables in my experiment are: height of ball dropped mass of ball material of the ball surface area of the floor temperature of the ball The variable I am going to control is the height of the ball dropped. The heights of which I am to drop the bouncing ball are 25cm, 50cm, 100cm, 150cm, 200cm and 250cm. Fair Test: To keep my experiment a fair test, I am going to keep the following variables the same: consistent measurements of the height of bounce mass of the ball material of the surface area of the floor the size of the ball Safety:

To make sure my experement is safe, I will do the following things: always ties up long hair so it doesn’t get in the way when taking measurements keep bags and books away while the experiment do not mess around while the experiment is taking place Apparatus: The apparatus I am going to require to carry out my investigation are: bouncing ball (material: plastic, weight: 5. 7 grams) 3 rulers: these are to measure the rebound from each distance weighing scales: to measure the weight of the ball masking tape: to hold the rulers on place on the wall so accurate measurements can be taken.

Method: The following instructions are how I am going to carry out my investigation: Measure the ball on the weighing scales Stick the rulers on the wall with the masking tape Start of with the height 25 cm and let the ball go Measure the height of the first rebound Record the results Then measure the height of the first rebound of the ball dropped at 50 cm.