The Bouncing Ball Experiment

Authors Avatar

The Bouncing Ball Experiment

A Ball Drops:

Energy is needed to do everything.  Light, sound, movement and heat are all examples of things that need energy to exist.  Energy is defined as the ability to do work – to make something happen e.g. to move something.  If something can apply a force over a distance, it has energy. The easiest way to detect energy is when it is changed from one form to another.  To then measure how much energy is present, we can measure the amount of work done whilst the transformation is occurring.

An object can store energy as a result of its position.   When a ball is held at a height, it stores energy.  This stored energy is referred to as potential energy.  It is called potential energy because the ball has the potential to drop (converting the potential energy into kinetic/movement energy), if it is let go of.  The higher the ball is from the ground, the more kinetic energy it will need to fall back down.  The kinetic energy is converted from the Gravitational Potential Energy the ball has when it is elevated. Gravitational potential energy is the energy stored in an object as the result of its vertical position.  The ball falls to the ground due to the force of gravity by converting the gravitational potential energy (GPE) into kinetic energy needed for the ball to move.  The higher the ball is elevated, the more GPE it has.   As the ball falls down, its GPE falls as it is converted into kinetic energy.  The amount of kinetic energy stored in the ball increases as more and more of the gravitational potential energy is converted.  The more kinetic energy the ball has stored, the faster it moves.  The ball increases velocity until it is blocked by something.

Similarly, a drawn bow is able to store energy as a result of its position.  When it is not drawn, it has no potential energy.  When it is drawn and held, it is altered from its usual equilibrium position and it has the potential to fling back into place if let go of.  This is called elastic potential energy.  The further back the bow is drawn, the more elastic potential energy it is given.  This is because it has further to travel to reach its usual place than it would have done and needs more energy to convert into kinetic energy so that it can move back.  

Gravitational potential energy is the energy stored in an object as the result of its vertical position (i.e., height). The energy is stored as the result of the gravitational attraction of the Earth for the object.

The higher a ball is dropped from, the more GPE it has, which is converted into kinetic energy and stored, making its velocity rise further and further as the ball loses GPE.  The more velocity/kinetic energy a ball has when it hits the ground, the more energy there is to be converted.

When the ball hits the ground, there is friction, which transforms some of the kinetic energy into thermal energy (heat) and often sound as well.  All the rest of the kinetic energy that hasn’t been wasted as thermal energy or sound will be transformed into elastic potential energy when the ball comes into contact with the ground.  When a ball hits a surface, all the kinetic energy it has stored is immediately transformed.  The floor, the ball or both become slightly dented out of shape as a result of the velocity and force they collided with.  As the ball and floor try to regain their original shape, they repel each other and immediately transform the elastic potential energy they have stored into kinetic energy.  This energy, now stored in the ball sends it into the air.  The more kinetic energy there was in the ball to begin with, the more energy there will now be left to convert back into kinetic energy.  The ball will rise, or bounce higher.  

 

If a ball were completely efficient, no energy would be lost during the bouncing process.  For this to happen, no energy can be lost with sound or thermal energy due to friction.  If a ball lost none of this energy whilst being dropped and hitting the floor, it would bounce to the same height as it was dropped from.  The ball needed a certain amount of kinetic energy to move from the height it was dropped from to the surface it hit.  If the ball were completely efficient, it would still have exactly that same amount of energy needed to move it the same distance back to where it was dropped.  Obviously, we do not have the technology at the moment to create a completely efficient bouncing ball so no ball can do this.  However, some balls are more efficient at not losing energy than others.

There are many other factors other than dropping height that affect the bounce height of a ball.  These factors are:

        Surface area of the ball

        Pressure inside the ball

        Material of the ball

        Material of the floor

        The force at which the ball is dropped by

        Accuracy of measurement.

I chose to control the height that the ball was dropped from because with the equipment I was given, I considered it to be the easiest factor for me to control.  Also, I felt that the other factors would be relatively easy for me to keep constant.  If I used the same ball each time, the surface area would always stay the same, as would the pressure inside the ball and the material of the ball.  If I conducted the experiment in the same place on the same surface for each height, the material of the floor could be kept constant.  The person dropping the ball would be the same each time.  They would always drop the ball without exerting any force on it at all; they would hold it lightly, and simply let it go.  This way, all the factors I am not measuring will remain as constant as I can make them.

Join now!

 

Aim:

For my investigation I want to investigate the effect of dropping height on the gravitational potential energy of my ball.  I want to prove or disprove my hypothesis relating drop height with bounce height.  I also want to work out where any lost energy in the experiment has gone.

The Preliminary Experiments:

I have chosen to use a ping-pong ball to investigate.  I chose a ping-pong ball for my investigation because after quickly testing each ball’s bounce height, I found that its bounce height was most suitable for use with the equipment ...

This is a preview of the whole essay