This is supposed to help us understand that light is also a particle, along

with being a wave.

This part is really hard to understand.

This part is really hard to understand.

No matter how bright the light was, if it was the wrong frequency, no

electrons were given off.

It is like a solar calculator. If the light in the room is bright, the calculator works. If the

lights in the room are off and the room is dark, the calculator does not work.

If the lights are on “a little”, the calculator does

not work “a little.” It does not work at all.

It is all or nothing.

Digital Cameras

While this may be the very first time that you have heard of the photoelectric effect, you have certainly made some use of it many times in your life.

The photoelectric effect is what makes digital cameras work. Any digital camera contains a grid of little metal “pixels” that become charged when they are illuminated.

This grid sits on what is called a CCD chip. So when someone takes a picture with a digital camera, the camera shutter opens and light spills onto the CCD chip. The image is then stored as the information about the charge on each pixel in the grid.

Your eye contains a similar, but biological version of a CCD chip: the “rods and cones” of your retina. While the nature of your eye is a bit different, it also relies on the photoelectric effect to see the world around you!

Hot, glowing metal is throwing out packet of energy, not waves of

light.

This packet of energy is called a QUANTA.

This packet of energy is called a QUANTA.

End