Next week I'm supposed to teach a unit on light. Can any of you give me some topics that might be covered in this unit? Our science curriculum doesn't offer much, and I want to be creative with some hands-on activities.
When we studied light two years ago with some friends, we just got some light from the library and what we walked away with was what I call "the three B's:"
1. You can block it. Play with shadows. Use opaque things, and things like wire window screens.
2. You can bend it. Use a prism.
3. You can bounce it. Use a mirror and have the kids direct a flashlight beam, "bounced" by a mirror, on the clock, the doorknob, etc.
After the three b's have fun learning about the speed of light. It takes about 8 mins. and 20 seconds for light to travel from the sun to the earth. Don't tell how long it takes, but tell the students that you will start a timer when you say "go" and you want them to guess when the light that left the sun on the word "go" will hit the earth. Say go and 8.33 mins. later the timer goes off. Did they guess right?
Get those little light paddles and have kids "mix" light. Light mixes differently than pigments.
Kids like doing those sun-art papers. They are blue photosensitive papers you can get from some school supply places. You put objects on the papers and put them in the sun and the sun fades the exposed paper, leaving shadows of the objects. The paper is a bit pricey. You can do the same thing, with less dramatic results, using dark construction paper. Natural objects like ferns look really nice, but you can also use things like combs, keys, and paper clips. Do this on a sunny, windless day.
Or, make silhouettes of the students' profiles using a large bright light in a dark room.
Show the students a laser pen. Remind them not to fool around with lasers and never to point the at someone's eyes.
See if you can find refraction grating glasses. I think either Edmund Scientific or Home Science Tools sells them by the dozen. They cost around a dollar each, if I remember right, maybe a little less. They have paper frames and cheap refraction gratings as lenses. Look at different types of light (fluorescent, incandescent, candle light, a spot of light from a laser pen, neon signs at night) and see the different halos each makes. If you have some chemicals around (and a book on safety!) you can burn crystals of copper, etc. and see that the flame is a different color and produces a different refraction grating halo. If you get enough of these glasses, you can send a pair home to keep with each student. That would be fun.
I have to teach that light travels in a straight line until it hits an object in which it is either absorbed, reflected or refracted. I show that light travels in a straight line by getting 4 different index cards and putting a hole in the middle of the 1st three. Then you line up the cards and shine a flashlight on the holes. The light should go though the wholes and hit the last card. Then we take one of the cards and move it so that the light will be absorbed. This is an investigation from my textbook.
The kids LOVE to see reflection. I normally take the kids to a bathroom that we can turn off all the lights and it has a mirror. I shine a flashlight into the mirror and have the kids find where the light BOUNCES (or reflects) onto the wall. Then we block the light (making shadows). For some reason they like to see the light bounce. It is like they get what reflection means.
I had my students figure out what materials would block light, let it through (somewhat), and let it through completely. I set up the center with baggies with aluminum foil, wax paper, tissue, cardboard, glass, add any others you think are interesting. (water)
give them a flashlight and let them figure it our by checking a list off.