My PBL Project

Driving Question: How much longer would it take an ice cube to melt on the cold block, as compared to one put on the warm block?

Concepts:

• Heat versus temperature

• Thermal conductivity

• Heat Capacity

Introduction: The blocks look very similar to each other. However, once they are handled observations can be made about the similarities and differences of the two blocks.

Materials: Ice Melting Blocks with O-rings, ice cubes

Procedures:

1. Touch both blocks. Which feels warmer? Which block will cause ice to melt faster?

2. Place the O-rings on the blocks to prevent water from flowing off. Place an ice cube on each block.

3. Observe the rates at which the ice cubes melt. Which material is conducting heat into the ice faster?

4. After a few minutes, remove the ice and water, and touch the blocks again.

5. The aluminum block felt cool at the beginning for the same reason that it melted the ice faster. It is better at conducting heat away from your hand, and makes your skin feel cool. Energy stored as heat inside the block was transferred to the ice when it melted. Now the block has less thermal energy than before.

Scientific Principles: The aluminum block has more heat capacity which is heat being transferred into the ice increasing the temperature causing it to melt. The wooden block is a poor conductor of heat that is why the ice is not melting as fast the aluminum block. An ice cube on the verge of melting is a °C. Transferring heat to the ice cube is necessary to melt it. Both of the blocks are at room temperature much warmer than °C and are able to conduct heat to the ice. However, the high heat conductivity of the aluminum block allows it to conduct heat rapidly on to the ice, resulting in rapid melting, whereas the low conductivity of the plastic causes very slow melting.

Pictures

ICE MELTING BLOCKS