Which of the following demonstrations best shows that solid water (ice) is less dense than liquid water?

• A. Heat water until it boils and observe the steam rising.
• B. Place an ice cube in a glass of water and observe that it floats.
• C. Add salt to water and observe it dissolving.
• D. Pour water into a container and measure its volume.

Answer: (B)

Verified step by step guidance

1. Understand the concept of density, which is defined as mass per unit volume, mathematically expressed as \(\text{density} = \frac{\text{mass}}{\text{volume}}\).
2. Recall that if an object is less dense than the liquid it is placed in, it will float; if it is more dense, it will sink.
3. Analyze the demonstration where an ice cube is placed in a glass of water: since ice floats, this indicates that solid water (ice) has a lower density than liquid water.
4. Compare this to other options: boiling water to observe steam, adding salt to water, or measuring volume do not directly demonstrate the relative densities of ice and liquid water.
5. Conclude that the best demonstration to show that ice is less dense than liquid water is placing an ice cube in water and observing it float.