Skip to main content

Which Hurts More?

212° F
Let's play a little game. I'll list a bunch of possible actions. Each action will have 2 variations, (a) and (b). You choose either (a) or (b), depending on which would be safer (or less painful). Each of the questions will involve an oven hot enough to bake a cake (350° F), and a pot of boiling water (assume we're at sea level). So... would you rather:

1.
    (a) Stick your hand in the oven
    (b) Stick your hand in the boiling water
  ... for a period of 10 seconds


2.
    (a) Leave a fork in the oven
    (b) Leave a fork in boiling water
  ... for a period of 15 minutes. Then hold the fork tight with your bare hand.


3. Fill a jar to the top with cool tap water. Then:
   (a) Place the jar in the oven
   (b) Place the jar in the boiling water
  ... for a specific, but unknown, period of time. Then remove the jar and put your hand in it.


First see if you can figure these out yourself. They shouldn't be too hard. If you have trouble, heat up your oven and boil a pot of water, and see for yourself what hurts more. (NOTE: I take no responsibility for any resulting injury.)

My solutions to the questions are: 1.a 2.b 3.a. Now answer this: is boiling water hotter than an oven? Or is the oven hotter?

As with any problem, the answer depends on the meaning of the question. In this case, the answer depends on the definition of "hot". If the definition of "hot" is "having a high temperature," then the oven is clearly hotter, because water boils at 212°.

That's boring, though. Let's try another definition from the online Merriam-Webster dictionary: "capable of giving a sensation of heat or of burning, searing, or scalding." Or in other words, "burns when touched."

What's hotter now? Let's try each question. In question 1, the boiling water is hotter. This is because the water burns a lot worse when you stick your hand in it.

But in question 2, the oven is hotter, because it gives a greater sensation of heat (via the fork). This is because the temperature of the oven is higher than the temperature of the boiling water; given enough time, the fork can slowly reach 350° in the oven, but will only reach 212° in the water.

In question 3, the boiling water is hotter. It quickly heats the jar to a temperature of 212°. The oven also heats it; however, unlike in question 2, the oven is not capable of heating it above 212°, because the water will boil away before it gets that hot.

As you can see the situation affects what we perceive as hot; sometimes, things feel hotter than they really are, and other times, things feel cooler than they really are. The reason for this has to do with how quickly the heat is transferred into our skin. If the heat is transferred slowly enough, an object with a temperature of hundreds of degrees might feel barely warm. This effect is what happens inside an oven, because air is not a good conductor of heat. On the other hand, if heat is transferred quickly, a much cooler object may feel much hotter. This is the case with the boiling water - although it has a temperature of only a couple hundred degrees, it can cause severe burns if it spills on skin.

This principle results in some weird consequences.

For example, a couple days ago I was changing the transmission fluid in my dad's car. After draining the black oil into a pan, I accidentally dropped a metal socket extension into the liquid. After a couple of minutes carefully tipping the container back and forth, trying to isolate the piece, I finally reached in and pulled it out.

The oil felt soothingly warm. As I wiped the oil off of the socket extension, however, I realized the metal piece was burning hot. The oil had heated it to the point where it was painful to hold.

I'd had no idea how hot the oil was. If somebody had asked me, I would have said it was warm. But after feeling how hot the bolt was, I knew what was really going on.

Sometimes our senses can deceive us, and we perceive a reality that is much different from what it really is. Humans simply aren't perfect. Which is why scientists rarely rely on one person's observations or calculations when attempting to prove or disprove a theory, and why testimonials aren't nearly as trustworthy as experimental analysis.

With a little knowledge and experience, though, people can learn about their weaknesses and compensate for them. So step outside a little, and try some new things. Maybe shove your hand in a pot of boiling water. Don't worry - it's not as hot as it feels.


New posts every month - subscribe for free!
Labels:

Comments

Post a Comment

Popular posts from this blog

Pluto No Longer on the Horizon

This morning, New Horizons became the first spacecraft to make a flyby observation of the Pluto system. During the mission, the spacecraft captured the most detailed photographs of Pluto's surface we've ever had, and possibly ever will have. It also found many new properties including size, mass, atmosphere, and surface composition. In a period of a few hours, we discovered more about Pluto than we've found in the 85 years since Clyde Tombaugh captured its first photograph. Before After  (images credit: NASA) To complete this mission, the spacecraft flew for more than 9 years through the emptiness of space. This may sound like a long time, but it's actually amazingly quick. In fact, New Horizons set the record for the fastest speed at launch, and during the flyby, the spacecraft was moving at a rate of over 30,000 mph, or roughly 50 times the speed of sound. Picture an object twice as heavy as a grand piano moving 25 times faster than a bullet from a gun. Yikes. The man...
2 comments
Read more

Flipping Quarters

Here's an interesting puzzle involving chance: A man in a park asks you to play a game with him. It's a form of gambling. To play, you must pay the man $5, then flip a coin repeatedly until you get heads. As soon as you get heads, you stop flipping. If you only flipped the quarter once, he'll give you $1. If you flipped it twice, you get $2. Three times, $4. Four times, $8. Each extra flip gets you twice as much money, so the longer it takes before you get tails, the more money you get. Should you play, if you have a lot of time and the man will play as many games as you want? How much money, on average, would you gain (subtracting the $5 fee)? I will give the solution in a later post .
1 comment
Read more

Should Tau Replace Pi?

The digits of π, organized in a very new way Happy π-day! And happy π-month! Today's month and day - that is, March 14 or 3.14 - includes the first 3 digits of π. And today's month and year - March 2014 or 3.14 - also includes the first 3 digits of π. We won't have another double-day for π for the next 100 years, so enjoy this one! For the special occasion, I'm posting two π-related posts - one for π-month, and the other for π-day. In both posts, I'm setting the font size to approximately π * π + π + π. This is the first post, for π-month; to see the second, go to http://greatmst.blogspot.com/2014/03/pi-month-pi-day-post-2-5-common-pi-myths.html . In this post, I am including an essay I wrote about whether π or τ is the more superior constant. This was written for people who know very little about math, so the basic idea should be easy to understand even for people who are not mathematically inclined. Should Tau Replace Pi? A constant is any number or value that ne...
Post a Comment
Read more