Energy can take one of two forms: matter and light (called electromagnetic radiation). Light is energy in the form of either a particle or a wave that can travel through space and some kinds of matter, like glass. We’re going to investigate the wild world of the photon that has baffled scientists for over a century.
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NEW! Download the complete packet for this section here.
Low electromagnetic radiation (called radio waves) can have wavelengths longer than a football field, while high energy gamma rays can destroy living tissue. We’re going to have a look at the nutty fellow called the ‘photon’ and its very odd behavior during two important experiments that, at first glance, seem to be in conflict with each other. The behavior of light is so strange that scientists are still trying to work out the details.
Imagine tossing a rock into a still pond and watching the circles of ripples form and spread out into rings. Now look at the ripples in the water and notice how they spread out. What makes the ripples move outward is energy, and there are different kinds of energy, such as electrical (like the stuff from your wall socket), mechanical (a bicycle), chemical (a campfire) and others.
The ripples are like light. Notice the waves are not really moving the water from one side of the pond to the other, but rather move energy across the surface of the water. To put it another way, energy travels across the pond in a wave. Light works the same way – light travels as energy waves. Only light doesn't need water to travel through the way the water waves do - it can travel through a vacuum (like outer space).
Imagine tossing a rock into a still pond and watching the circles of ripples form and spread out into rings. Now look at the ripples in the water and notice how they spread out. What makes the ripples move outward is energy, and there are different kinds of energy, such as electrical (like the stuff from your wall socket), mechanical (a bicycle), chemical (a campfire) and others.
The ripples are like light. Notice the waves are not really moving the water from one side of the pond to the other, but rather move energy across the surface of the water. To put it another way, energy travels across the pond in a wave. Light works the same way – light travels as energy waves. Only light doesn't need water to travel through the way the water waves do - it can travel through a vacuum (like outer space).