Science of Light

Science is Illuminating

Today 3rd graders learned that light travels in a straight line.  You can demonstrate this with a flashlight and a little dust in the air.

When light hits a new substance it might bend or bounce!

We tested this out with water and a Popsicle stick.  It looked like the stick was bent, but it was just light bending when it went from air to water.  Water slows light down so it changes direction.  We also made a penny disappear using refraction!

We explored reflection while bouncing a light off of two (or even more) mirrors to hit a target!

White light is actually made up of all the colors of the rainbow, just ask Roy G. Biv

We used special glasses to break up white light, but you could use a prism, a CD, bubbles or even a garden hose to see this!

Really, only Roy G. Biv's initials are needed to make white light.  Red, green, and blue light are the primary colors which combine to make white light.  We used our red, green, and blue lights to make white light on our desks.

Reflection also tells our eyes what color an object is.  If an object is blue, it will absorb all the colors of light EXCEPT blue.  Blue is reflected to our eye.

White light touches the object, only blue light is reflected, the rest of the light colors are absorbed.

White light touches a red object, and the red light is reflected.

White light touches the object, but only green light is reflected.

A white object reflects all of the colors, so we see white.

A black object absorbs all the light (including some we can't see).
That is why you are hot when you wear a black shirt on a hot day!

Interestingly, if you shine a green light on a red shape it looks black (because there is no red light to reflect and the object absorbs the green light.)  

We explored a shape of a mystery color and used different colors of light to find out what color the shape was!

Try your hand at moving mirrors in this fun activity from Science Kids (click on the link below.)  There is also a game called Khet you can buy which uses this same concept.
Mirror activity

The University of Cambridge Department of Engineering also has a game you can use your light knowledge to arrest an alien!
Engineering and Light