Lesson eLearning

Which of the following is the best way to keep a 1‑litre bottle of water cool while playing outside on a hot day?

medium MCQ 2 marks Class 5 · EVS · Blow Hot Blow Cold
  1. Place it in a sunny spot.
  2. Keep it inside a plastic bag.
  3. Cover it with a wet cloth and keep it in shade.
  4. Fill it with ice water.
Answer
Cover it with a wet cloth and keep it in shade.

The correct answer is Cover it with a wet cloth and keep it in shade. — Evaporation removes heat from the water, keeping it cooler.

Step-by-step solution

  1. Heat from the sun tends to warm the bottle.
  2. Covering it with a wet cloth increases surface area and promotes evaporation.
  3. Keeping the bottle in shade reduces direct solar heating.
  4. Evaporation removes heat from the water, keeping it cooler.
Common mistake: Choosing a sunny spot instead of shade

Concept tested: Heat transfer by evaporation

Published · How this solution was prepared and checked

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