By Tricia Lobo – Updated Aug 30, 2022

This hands‑on activity bridges classroom thermodynamics with everyday life. By building a homemade ice keeper, students apply the core principle that heat flows from hotter to cooler regions, and they learn how insulation can delay that transfer.

Step 1

Seal a 3‑by‑3‑by‑3‑inch block of ice in a resealable plastic sandwich bag. Ensure the bag is airtight to prevent moisture loss.

Step 2

Choose an insulating material and line the interior of a shoebox. Common options include newspaper, plastic foam, or foam packing peanuts. Experiment with different materials to gauge their insulating performance.

Step 3

Place the sealed ice bag inside the shoebox. Keep the lid closed as much as possible; frequent opening introduces warm air that accelerates melting.

Step 4

Every hour, gently peek to see whether the ice is melting. Measure the ice block’s dimensions each time and calculate its volume. Plot time against volume to visualize how well your design preserves the ice. A slower rate of volume loss indicates better insulation.

Step 5

Use the graph to evaluate the effectiveness of your ice keeper. Identify the most successful insulating material and consider additional ways to further slow the melting process.

Things Needed

• Shoebox
• Resealable plastic sandwich bag
• Insulating material (e.g., foam packing peanuts, plastic foam, newspaper)
• 3‑by‑3‑by‑3‑inch ice block

TL;DR (Too Long; Didn’t Read)

Promote sustainability by using only recycled materials for insulation.