Why do ceiling fans accumulate dust even though they move so quickly?
Correct answer: D. The electrostatically charged fan blades attract dust particles
- A. Dust sticks to the rust in fans
- B. The momentum of the fan is so high that the dust particles which have low inertia are instantly caught in the motion of the blades and adopt the motion of the blades
- C. The dust settles in and sticks to fans when they are not moving
- D. The electrostatically charged fan blades attract dust particles
Explanation
The correct answer is that the electrostatically charged fan blades attract dust particles. As the fan blades move rapidly through the air, they generate friction with air molecules. This friction can lead to a static charge building up on the blades, which then attracts dust particles. This phenomenon occurs even when the fan is in motion, making this explanation the most plausible. The other options do not account for the electrostatic attraction: rust is not a significant factor, dust settling when stationary doesn't explain accumulation during motion, and momentum does not cause dust to adhere.
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Scientific reasoning evaluates hypotheses through observations, variables, controls, measurements and experimental results. Questions involve identifying independent and dependent variables, recognising a fair test, interpreting tables or graphs, distinguishing evidence from opinion, and deciding whether data supports, rejects or leaves a hypothesis unresolved.
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