Puzzle Corner

Though not a "puzzle" per se, this optical illusion has always unnerved me. Squares A and B are the same color.

This one is maybe too easy and well-known, but it's one of my favorites to do with my students...

A windowless attic contains three identical light fixtures, each containing an identical light bulb. Each light is connected to one of three switches in the basement. Each bulb is switched off at present. You are in the basement with the three switches. 

Before walking up to the attic, you have 15 minutes in the basement to touch the switches. But once you've left the basement, you may no longer touch a switch. After this, you go directly upstairs to the attic and must identify which light fixture goes with which switch. 

How can you tell which switch goes with which light?

Show contentSpoiler:

Heat.

Though not a "puzzle" per se, this optical illusion has always unnerved me. Squares A and B are the same color.

Ditto.

[Laird]

This one is maybe too easy and well-known, but it's one of my favorites to do with my students...

A windowless attic contains three identical light fixtures, each containing an identical light bulb. Each light is connected to one of three switches in the basement. Each bulb is switched off at present. You are in the basement with the three switches. 

Before walking up to the attic, you have 15 minutes in the basement to touch the switches. But once you've left the basement, you may no longer touch a switch. After this, you go directly upstairs to the attic and must identify which light fixture goes with which switch. 

How can you tell which switch goes with which light?

A clarifying question which might give the game away, thus hidden away in a spoiler:

Show contentSpoiler:

Are we assuming light filaments which transfer their heat to their bulbs over time?

This one is maybe too easy and well-known, but it's one of my favorites to do with my students...

A windowless attic contains three identical light fixtures, each containing an identical light bulb. Each light is connected to one of three switches in the basement. Each bulb is switched off at present. You are in the basement with the three switches. 

Before walking up to the attic, you have 15 minutes in the basement to touch the switches. But once you've left the basement, you may no longer touch a switch. After this, you go directly upstairs to the attic and must identify which light fixture goes with which switch. 

How can you tell which switch goes with which light?

It foxed me initially, but

Show contentSpoiler:

I suppose you switch one bulb on for 15 minutes, then switch that off and a second one on. The first bulb will be hot and dark, the second light and the third cold and dark.

[Laird]

Though not a "puzzle" per se, this optical illusion has always unnerved me. Squares A and B are the same color.

Maybe a way to reinnervate yourself: consider, perhaps, that your brain is doing you the favour of subtracting the shadow from B. Is this what's really going on? I don't know, but it sure is a possibility. I'm open to evidence that it can be disqualified if anybody has any.

During a recent census, a man told the census taker that he had three children. When asked their ages, he replied, "The product of their ages is 72. The sum of their ages is the same as my house number." The census taker ran to the man's front door and looked at the house number. "I still can't tell," she complained. The man replied, "Oh that's right, I forgot to tell you that the oldest one likes chocolate pudding." The census taker then promptly wrote down the ages of the three children. How old are they?

A clarifying question which might give the game away, thus hidden away in a spoiler:

[/spoiler]

Yes, exactly.

This one is maybe too easy and well-known, but it's one of my favorites to do with my students...

A windowless attic contains three identical light fixtures, each containing an identical light bulb. Each light is connected to one of three switches in the basement. Each bulb is switched off at present. You are in the basement with the three switches. 

Before walking up to the attic, you have 15 minutes in the basement to touch the switches. But once you've left the basement, you may no longer touch a switch. After this, you go directly upstairs to the attic and must identify which light fixture goes with which switch. 

How can you tell which switch goes with which light?

Show contentSpoiler:

This puzzle may no longer work in the setting of cool to the touch LEDs.

I did a little test. The base of a standard LED bulb got warm. I don't know if would stay warm enough to still be noticeable, after the climb from the basement to the attic.

It might. I just went and rechecked the base after typing the above and it still was noticeably warm.

Linda

During a recent census, a man told the census taker that he had three children. When asked their ages, he replied, "The product of their ages is 72. The sum of their ages is the same as my house number." The census taker ran to the man's front door and looked at the house number. "I still can't tell," she complained. The man replied, "Oh that's right, I forgot to tell you that the oldest one likes chocolate pudding." The census taker then promptly wrote down the ages of the three children. How old are they?

Question:

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Are we supposed to assume that he wouldn't refer to a twin as the "oldest one"?

Linda