Cool Science: How Refrigerators Work & Old-Time Ice Secrets

This week on Discovery Rangers, we're exploring the cool science of how refrigerators keep food fresh and how people kept things cold before electricity! Your mission is to become a heat detective and see how heat moves around your home.

The Big Question

How does heat move, and how can we "trap" the cold?

What You'll Need

• Two identical glasses
• Water
• Ice cubes
• A kitchen towel or cloth

Mission Steps

1. Fill Glasses. Fill both glasses with the same amount of room-temperature water.
2. Add Ice. Add the same number of ice cubes to just one glass.
3. Wrap One. Tightly wrap the glass with ice cubes in the kitchen towel. Leave the other glass of ice unwrapped.
4. Observe. Check on both glasses every 15 minutes for an hour. Feel the outside of each glass.

Talk About It

• What did you notice about the glass that was wrapped in the towel?
• Where do you think the heat came from that melted the ice?
• How is wrapping one glass like how a refrigerator works?

Take It Further

For older rangers, try this: place one glass of ice in a sunny spot and the other in a shady spot. Which melts faster and why? This helps explore how different environments affect heat transfer.

FAQ

Q: My ice melted really fast, even in the wrapped glass. What happened? A: Even with the towel, some heat from the room still reached the ice. Towels slow heat transfer, but don't stop it completely. Q: Do I need to use a real towel? A: Any thick cloth that can trap air will work well to show how insulation helps. Q: Can I do this with warm water instead of ice? A: Yes! You could wrap one glass of warm water and see which glass stays warmer for longer.