This perplexing problem might take you back to junior high science class, where you learned about volumes, liquids, solids, and many of the physical properties they hold.
Hopefully you’ve retained some of that knowledge; here’s a problem that will put your understanding of physical properties to the test!
Just like science class, this puzzle has a few twists that may seem counterintuitive. Don’t let appearances fool you. See if you can solve the following problem:
Inspect the four glasses of water below. All are the same size and are filled to the same level. Which glass contains the most water?
Ponder the glasses and their contents, and when you think you know the answer, scroll down below to see the solution.
Need a hint?
You’ve probably realized that the law of displacement is at play here, and that will definitely affect the volume in each glass; what you might not have considered is that another property is meaningful in this situation. Think buoyancy.
Look again. Notice anything strange?
Answer: glass 4 contains the most water.
That’s right, a trick!
The rubber ducky bath toy was not inside the glass but hiding behind it. As all the glasses are the same size and filled to the same level, the glass with NO OBJECTS to displace the water inside it—glass 4—must contain the most water.
Unfair, you say? We say it’s fair! We hinted that buoyancy was an important consideration: keen observers would have noted that rubber duckies do not sink (unless they are pushed under); they float.
Therefore, the yellow ducky could not have displaced any water, and the only logical explanation would be that it was behind the glass (thus making transparency yet another important property at work here)!
If it’s any consolation, though, those who overlooked this deception and guessed glass number 2 were on the right track. The paperclip would have displaced the least amount of water—if only the rubber ducky were, in fact, a leaden ducky.
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