Light Energy

Light is a form of visible energy emitted by hot objects.

waves-the way light travels

visible spectrum – the light energy that humans can see

beam, ray – stream of light pointed in one direction

concave lens–  thinner in the middle and thicker at the edges, examples:  found in eye glasses, binoculars

convex lens- thicker in the middle and thinner at the edges, examples:  found in microscopes and telescopes 

transparent – a substance that allows most of the light to pass through it

translucent – a substance that allows some light to pass through it

opaque – a substance that does not let light travel through

absorption-when an object soaks up some of the light waves and transfers them to heat energy

diffraction – how light bends as it passes around an object

reflection – when light bounces off of an object

refraction – when light is bent as it moves through one kind of matter to another

rainbow – arch in the sky formed by the refraction of sunlight through raindrops

shadow – shape produced by light being blocked by an opaque object

prism – something that bends light, but is not a lens

color- wavelengths visible to the human eye as a result of the way the object reflects or emits light, example: a red apple reflects red light 

​Light waves travel in straight lines called rays.

Light must have a source that the waves travel from.  The Sun, fire, flashlights are a few examples.

Light does not need a medium to travel through.

The colors in the rainbow are called the visible spectrum because humans can see them.

Remember ROY G BIV, the rainbow colors by wavelength.  (red, orange, yellow, green, blue, indigo, violet)

Red has the longest wavelength and violet the shortest.

White contains all the wavelengths of the visible spectrum, so when most of the light is reflected, you see white.

A black object absorbs all colors equally and reflects none, so it looks black to us.

Reflect means bounce back to our eyes.

The smoother and shiner the object is, the better it reflects.

Some objects absorb light and turn it to heat energy.  Think of wearing a black shirt in the summer.

Refract means that light waves bend as they move from one medium to another.

 Lenses bend light to help us see things better.

Light waves travel way faster than sound waves.

Objects you can see through are called transparent.

Objects you can't see through are called opaque.

Objects that scatter light and cause a distorted image (think wax paper) are called translucent.