Great idea @worriedguy. I wouldn’t be surprised to see that show up on the market one day.
I did a project in grade school that went over big time. This is applicable to 9th grade as well, if you understand the concepts. I grew up a photographers son so I understood the concepts very early on.
It would encompass Time Travel, Photography and Invisibility. The fun part is that the whole class could take part in it.
Basically, it’s an experiment in long exposure. Get your EV (exposure value) set for the time necessary for someone to cross a 10’ area. Let’s say that is 3 seconds. You will have to set your ISO and aperture to expose properly for a 3 second exposure, with no flash. You may need to use neutral density filters to adjust for that exposure. But with the classroom lights out, and shades pulled, I’ll bet your exposure would be somewhere around 3 seconds at f8 with 100ISO.
Have someone (or the whole freaking class) stand on one side outside of the frame. They are to walk from one side of the picture to the other during the image capture of 3 seconds.
Assuming my estimate is correct (you may have to adjust) the image should show a teachers desk and a chalkboard with a blurred wavy stripes running through it horizontally. That’s the people crossing the photo during a 3 second exposure. You are actually demonstrating time travel from point A to point B.
Now keep your EV the same but change settings of shutter and f/stop. Go to 6 seconds at f/11. The exposure will look identical, but the people won’t even show up this time. They will literally be invisible.
Now let everyone dance around in front of the camera at 12 seconds at f/16. Have some people stand perfectly still, but wobbling their heads only. Some people will be invisible, and some will have bodies but no heads.
The experiment is designed to determine how short or long of an exposure is necessary to capture a moving object on film, or make it invisible altogether. It would actually be more fun to have a camera tethered to a computer or even a projector so everyone could see the results right away.
I had to do mine with polaroid film 40 years ago. Have fun!