This is a simple yet cool thing to do that creates a very neat effect with dust. This is my first instructable so go easy :)
Step 1: Materials!
1. a rectangular cardboard box (size is up to you)
2. air compressor
3. a nozzle with a button on the compressor hose (optional i guess)
4. dust (i got mine at a baseball field)
5. x-acto knife
6. something to sift the dust
Step 2: Begin
First we want to cut any flaps off the open end of the box. Then cut a hole about the size of your nozzle in the closed side. You can carry this out however you want.
Step 3: Attach Hose
Just put the nozzle into the newly cut hole in your box. It should fit somewhat snug. Give it a test it you want (most of the air should come out the open end)
Step 4: Get Some Dust
I "borrowed" some dust from a baseball field. Anything you want works really (I don't suggest rocks) Then put it into a container. I used a net to sift the dust (you don't really HAVE to do this but it helps). That way there's no rocks in it.
Sorry no pic for this one (it just rained and everything was wet at the time)
Step 5: Prepare the Cannon
Now just put some of the sifted dust into the box. Make sure you put the hose in so it doesn't run out the other end. Turn on your compressor and let it build some pressure. Now the final step! Press the button on the nozzle (or whatever) and watch the dust fly!! It's almost like a fog machine to give you an accurate picture. Move the nozzle or the box around to get maximum effect. After a few minutes you should still have quite a bit of dust in their. DISCLAIMER: I TAKE NO RESPONSIBILITY OF ANY INJURIES DUE TO THIS PROJECT. DON'T BE STUPID WITH THIS. AIR COMPRESSORS CAN BE DANGEROUS IF MISUSED. DO NOT AIM IT AT SOMEONE. THE DUST OR ANY ROCKS COULD DAMAGE SOMEONE'S EYES.
Not great pics I know. But that's all I could get.