Ever seen your reflection in a piece of aluminum foil? Much like a real mirror, the foil shows you your reflection by, um, reflecting visible light back at you. But what if that reflected light were to go astray? Breaking a mirror is too dangerous to do with a bunch of smelly kids around—not to mention seven years of bad luck—so use ye olde reflecting foil to teach your students (or whoever) about the properties of light and reflection.
Look At Those Ugly Mugs
For this handy dandy Demo Science science demo, all you’ll need is a roll of aluminum foil and a scissor. To start out, each student will need their own square of foil to act as their “mirror.” Kids’ faces are pretty small, so you can cut a piece from a standard-width roll in halfsies (width-wise) and still have it be big enough.
Definitely use a scissor to cut all your foil squares, as ripping or tearing the foil will likely produce wrinkles, and wrinkles must be avoided at all costs at this stage of the game. If you’re a real stickler for precision, you can get yourself some die cutting equipment and crank out perfectly-sized pieces over and over.
Now that each kid has his or her own foil mirror, and their reflections have doubled the number of ugly little faces in the room, have them play with the foil (shiny side facing them, of course), tilting it this way and that and watching as their reflections change with the direction of the foil. They should be careful to avoid wrinkles still.
Then, have them crumple their foil mirrors into loose wads. Make sure they know not to ball them up too tightly, as that will make the next step nigh impossible.
That next step? Flattening their crumpled foil back out. Students should be encouraged to smooth the aluminum foil out as much or as little as they like, as differently crumpled-and-flattened pieces will provide different results.
Have the kids look at the shiny side of the foil now. Their reflections will no longer be visible. But why?
Because Science, That’s Why!
By balling up their foil, your students broke the nice, smooth, consistently reflective plane its shiny surface provided. Now, post-crumpling, the ridge-filled surface still reflects light, just not in a straight line. Rather than reflecting your image back at you, the light now reflects in countless directions and at different angles.
By moving and tilting the foil as they did before, students may be able to recapture part of their reflections, but they’ll never again get as clear a view as they first did.