Make Running Spiders
Wrap a marble in foil, draw a spider on top, and watch it skitter across the table.
Materials you'll need
- aluminum foil
- black permanent marker
- scissors
- glass marbles (one per spider)
- metal baking pan (optional, as a tray and a play arena)
Step-by-step tutorial
Step 1: Tear off a sheet of aluminum foil and lay it flat. Use a black permanent marker to draw several fat, leggy spiders on it, leaving space between them so you have room to cut.Step 2: Cut around each spider with scissors, making a rough circle of foil. The circles don't need to be neat, and you want extra foil around the drawing to wrap with.
Step 3: Turn a circle over and set a marble in the middle of the plain side. Lightly fold the foil up around the marble so it's held loosely with the spider facing out, and resist the urge to squeeze it tight. Marbles are a choking hazard, so keep this project away from kids under three.
Step 4: Repeat with the rest of your circles until you have a whole batch of spiders. A metal baking pan makes a handy tray for corralling your marbles and your finished spiders.
Step 5: Set your spiders on a smooth, flat surface and give each one a gentle push. Watch them skitter, wobble, and veer off course like they're running.
Learn more
The secret is the marble. When a flat object slides across a table, its surface rubs the whole way, and that rubbing, called sliding friction, brings it to a stop almost immediately. A round marble rolls instead of rubbing, so it loses far less energy and keeps going long after your push is over. That's inertia at work: a moving object keeps moving until a force like friction slows it down. The crinkled foil is what makes it look alive, because its bumpy, lopsided edges catch the table at random spots, so your spider wobbles and swerves instead of rolling in a neat straight line.If running spiders were a hit, Marble Roller Coaster levels up the marble game with a track kids build themselves, where the height of the first drop decides how fast the marble finishes.