Question

p.5.5.4.4 - make and test predictions about how the density of an object affects whether it sinks or floats when placed in a liquid. q1. why does a log float in a river? a. it is denser than water b. it is less dense than water c. it has no density d. its mass is larger than water

Explanation:

To determine why a log floats in a river, we use the principle of buoyancy: an object floats in a fluid (like water) if its density is less than the fluid's density.

• Option A: If an object is denser than water, it sinks, so A is incorrect.
• Option B: A log floats because its density is less than water's density, so B is correct.
• Option C: All matter has density, so C is incorrect.
• Option D: Floating depends on density (mass per unit volume), not just mass. A large - mass object with low density (like a log) can still float, so D is incorrect.

Answer:

B. It is less dense than water