So even though the four glasses may look equally full, their actual amounts of water can be different.
The Correct Answer Is Glass A
Glass A, the one containing the paper clip, contains the most water.
Why?
The paper clip is much smaller than the other objects. It occupies less space inside the glass and therefore displaces less water.
The baseball, eraser, and wristwatch all take up more space.
So, in simplified form:
Smaller object → less displacement → more room for water
That’s the trick.
Why Is This Puzzle So Easy to Get Wrong?
Our eyes naturally focus on the water level.
When four glasses appear to have the same level, the immediate assumption is that they contain the same amount of liquid.
But the objects inside the glasses change the amount of available space.
This is a great example of why visual puzzles can be deceptive: what you see first isn’t always the whole story.
The Science Behind the Trick
Imagine removing every object from its glass while keeping the glasses otherwise unchanged.
The glass that contained the smallest object would have the least displaced volume. If the visible water levels were initially the same, that glass would therefore have the greatest volume of water.
