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27 votes
Accepted

How does the mirror know what’s behind the paper?

Perhaps a diagram would help? Excuse my poor artistry: Clearly, you can see that there is a trajectory a ray can take which starts at the top of the egg, hits the mirror, and then intersects your eye....
Riley Scott Jacob's user avatar
17 votes

Rotating a Pot of Boiling Water on a Stove

When you rotate the pot, you are jiggling the pot and stirring up the boundary layer between the pot surface and the bulk water. Shaking & stirring the water increases the chances of temporarily ...
niels nielsen's user avatar
15 votes

How does the mirror know what’s behind the paper?

The other answers are quite right, of course, but I thought it might be helpful to know the comic has a second page in which Aki Hayakawa explains how mirrors work. This prompts a rather... crude ...
Sturrum's user avatar
  • 424
6 votes

Rotating a Pot of Boiling Water on a Stove

Bubbles generally need a focus point to determine where they form to nucleate the formation of the bubble. If you happen to have a pot that has an imperfection such as a scratch on the bottom, you ...
KDP's user avatar
  • 4,473
5 votes

Rotating a Pot of Boiling Water on a Stove

What is the type of stove you have? Gas flame? Electric burner? Other? Your description fits excellently with an exposed electric burner stove. The pan does not sit perfectly on the burner. ...
BowlOfRed's user avatar
  • 40.4k
5 votes

How does the mirror know what’s behind the paper?

Is it not just a matter of at which angle you are and how is constructed the reflection? The reflection is just the brain trying to reconstruct the position of the object by continuing the ray of ...
Syrocco's user avatar
  • 1,123
5 votes

Why can you hammer a hole into an underwater ceramic cup?

Not an answer, but I did the experiment and it works (mostly) and you can't put photos in comments. The nail drove a neat looking hole in the cup. Turning the cup over revealed that the interior had ...
g s's user avatar
  • 13.8k
3 votes

Does a rubber mat reduce the impact to the floor below?

If dropped, the falling barbell will carry a considerable amount of kinetic energy when it hits the floor. Preventing damage to the floor involves managing that impact energy. Here is how to do it: A ...
niels nielsen's user avatar
1 vote
Accepted

Why clothes keep us warm?

Your thought experiment is to have only thermal conductivity to draw heat away from someone. In one case, the thermal layer is air. In another, it is a layer of clothing. This is a problem with a ...
Jeffrey J Weimer's user avatar
1 vote

Why clothes keep us warm?

Air next to your skin gets warm and then carries heat with it as it moves away. Reducing this is key. Down does it by trapping air between feathers. One cotton shirt is very little help on a cold day. ...
mmesser314's user avatar
  • 39.6k
1 vote

Is it possible to see thermal columns?

The refractive index of air is often taken to be one, but in fact it's slightly higher. Under normal conditions it's about $1.0003$. To a good approximation the refractive index minus one is ...
John Rennie's user avatar
1 vote
Accepted

Why do large trucks have a longer stopping distance than cars?

The stopping distance difference between large trucks and cars is what you'd expect based on the sources cited in the question. If a typical passenger car initially travelling at $55$ mph stops in $...
David Bailey's user avatar
  • 11.4k
1 vote

Can a pot become hotter when the stove is on?

You're thinking about it wrong. For this scenario, think of heat as a process, not a state. You are not "setting" the temperature to 400; you are setting the rate at which heat goes into the ...
fectin's user avatar
  • 111
1 vote

Doubt in pitch of screw gauge

Consider a screw that has been partially driven into a block of wood. The screw has cut a thread in the wood and the when the screw is rotated the helix of the screw itself remains in the precut ...
KDP's user avatar
  • 4,473
1 vote

Would placing sand bags over the top of a car's strut housing reduce the jarring impact felt when the car hits a pothole?

For a given spring stiffness, adding mass to the body of the car (this is called sprung mass) will inertially clamp the car body, reducing its tendency to bounce up sharply when you run over a pothole....
niels nielsen's user avatar

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