Lesson eLearning

When you leave an open glass of water in the sun, the water disappears. Why?

easy MCQ 1 mark Class 3 · EVS · Water O Water
  1. It is eaten by insects
  2. It turns into steam
  3. It sinks to ground
  4. It is used for drinking
Answer
It turns into steam

The correct answer is It turns into steam — So the water appears to disappear because it has turned into steam.

Step-by-step solution

  1. The glass is left open, so air can reach the water surface.
  2. Air around the glass contains water vapour.
  3. The sun heats the water, increasing its temperature.
  4. Heat causes water molecules to gain energy and move faster.
  5. Fast moving molecules escape from liquid as steam into the air.
  6. The water level in the glass therefore drops.
  7. So the water appears to disappear because it has turned into steam.
Common mistake: Thinking the water is absorbed by the ground

Concept tested: Evaporation

Published · How this solution was prepared and checked

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