# Energy > energy transfers

Examples of apparatus and demonstrations that can be used to illustrate different energy transfers and generate discussion.

The classic experiment to show that light can radiate across a vacuum, but sound requires a medium through which to travel.

Students make measurements on the energy transfers involved when a falling mass drives an electrical generator, and calculate the efficiency of the process

Students make direct measurements of power in various electrical circuits using an energymeter, and use values of voltage and current to calculate power.

Simple demonstrations to introduce the concept of kinetic (motion) energy.

The simple pendulum used as a stimulus to discuss energy transfers.

Roll a ball on a curved track to explain Galileo's idea, which in turn led to Newton's First Law of Motion.

Electric current transfers energy from the battery or power station to a lamp.

Simple demonstrations to stimulate discussion about transfers between kinetic (motion), gravitational and other forms of energy.

Students ‘experience’ forces and reinforce their understanding of force and energy units.

Using a dynamics trolley on a steep ramp, where the energy transfer is not easily measured.

Measuring the gravitational potential energy transferred to kinetic (motion) energy with a dynamics trolley.

Comparing the energy supplied from a stretched elastic band with the kinetic energy gained by a dynamics trolley.

Comparing the energy stored by two rubber bands.

To move along a horizontal plane there is no net transfer of energy from potential energy to kinetic (motion) energy.

The transfer of energy through an electric motor to potential energy of a load.

Collisions between trolleys that result in energy being dissipated to the surroundings.

Energy transfers using a model steam engine.

In elastic collisions the kinetic energy (KE) is conserved. In inelastic collisions the KE 'goes somewhere'. But where? This demonstration helps students picture a possible route for loss of KE.

When a pendulum is displaced, it gains gravitational potential energy due to its increased height. When subsequently released, this energy becomes transferred to kinetic energy. This datalogging experiment explores the relationship between these changes of energy.

Friction spoils the downhill and uphill experiment of a rolling ball on a curved track. This is Galileo's almost frictionless version of it.