Step-by-step tutorial
Step 1
Prepare the gelatin as directed on the package. Pour about one inch into a clear cup and allow it to set.
Step 2
Add the same amount of water to a second cup.
Step 3
Hold the laser pointer against the side of the water cup and turn it on. Look straight down into the cup. What do you see?
Step 4
Do the same for the gelatin cup. What do you see?
Tip
Remember, don’t point the laser directly into your eyes!
Fact
Did you ever wonder why you can’t see a laser beam as it travels across the room? We only see things when light hits our eyes. When the super-focused laser beam crosses the room, there’s nothing in the air to reflect some of that laser light back to your eye. So the beam is invisible!
Point the laser at the gelatin cup, however, and you DO see the laser beam. That means that something is getting in the way of the beam and bouncing some light into your eyeballs. And that something is the gelatin! Desserts made with gelatin are soft and jiggly because there are tiny pockets of liquid trapped inside a kind of gelatin skeleton. Light can pass through the liquid (like it does with the water), but it reflects off the solid gelatin. That reflected light is what lets you see the laser beam as it shines through the cup.
Try shining the laser at the gelatin from different angles. What do you notice? The laser beam bends! That’s because light can change direction when it passes between different materials (like air to gelatin).
