Energy can exist in many different forms. For example; light, heat, chemical, kinetic, potential and electrical.
If a rock is pushed off a cliff, potential energy is converted into kinetic energy. Potential energy is the energy a piece of matter has because of its position. (That is position in a gravitational, magnetic or electrical field.) Kinetic energy is the energy an object has due to its movement.
Observations made in the 19th century led to the conclusion that energy cannot be created or destroyed - just converted to other forms. This is known as the first law of thermodynamics or conservation of energy. Thus it is impossible to make a so called perpetual motion machine or a machine which generates energy.
Like the wind, it is impossible to see electrical energy, however its effects can be observed. (Try touching an electric fence - you will become aware of the energy very quickly!) Every day you use equipment which converts between energy types. For example a light bulb converts electrical energy to light energy. A car converts chemical energy to kinetic energy.
Test your understanding of these concepts using the Java Applet below. Click in the blank squares until the appropriate True/False answer is displayed. Once you've answered all three questions click on Check to have your answers marked.
Click the right arrow to continue with the next lesson.
You are person number to visit.