If you’ve browsed around my blog, you might have noticed a link at the top called Random Ideas. As the name suggests, it’s a page where I write down random ideas I have that aren’t big (or relevant) enough to warrant a blog post.
I usually update it when I think of something cool, which is once every couple of months. And just a few days ago, I thought of two things in one day. So I figured I’d throw them into a blog post for you 
(My blogging’s been a little lazy lately because I’m in the middle of my exams. Don’t worry, in a week and a bit, I’ll be back to usual.)
Why does hot soup cool down?
We were discussing this with a friend. It all started with the simple question:
Why does blowing on soup make it cool down faster?
My explanation is that hot soup cools by evaporating. Blowing on the soup replaces the humid air above the soup (already pretty saturated with evaporated soup) with dry air, which lets the soup evaporate faster, and so cool it down.
The soup cools down in the same way that a wet t-shirt makes you really cold. Evaporation literally sucks away heat energy from the unevaporated parts.
So I posted the question on twitter. And several people argued that hot soup cools by heat conduction. I mean sure, it does. But how much, really? Air is a notoriously bad heat conductor – it’s why clothing keeps you warm. The clothing itself does very little, but the layers of air between clothing act as a great insulator!
So I was thinking, maybe we could design an experiment. Have:
- A bowl of soup under normal conditions
- A bowl of soup with a fan aimed at it, thus producing constant blowing
- A bowl of soup in a small, closed container, which would quickly saturate with humid air and stop further evaporation
Unfortunately, the small container would not only stop evaporation, it would stop hot air from leaving, which would keep the soup hot even if the Heat Conduction Soup Cooling Hypothesis supporters are right
Oh well, I guess one of the greatest mysteries of the universe remains unsolved…
(Note: I am by no means convinced hot soup cools mainly because of evaporation. I just wanted to present my arguments for why it might do.)
The dirty laundry metaphor for life
I was doing my laundry the other day, and somehow I found myself contemplating the phrase “Eternal cycle of dirty laundry”. Which lead me to make a bunch of metaphors between laundry and life, just for the fun of it 
Here they are:
- Life is like doing dirty laundry. Shit will always keep piling up, and whenever you think you’re just about done, a whole new bunch of shit will come along. It’s okay, that’s how life works. It makes it more fun
- Troubles in life are like dirty laundry. They keep coming, and if you don’t deal with them, they’ll just pile up until they stink so much you will HAVE TO deal with them. So treat trouble like dirty laundry – whenever they come up, just deal with them, and then get back to your life. There’s no point in complaining about dirty laundry, it will keep coming anyway.
- Problems are like dirty laundry. They seem disgusting and smelly, but when you take the time to deal with them, they turn into a heap of fresh, wonderfully aromatic laundry that makes you happy and proud. And without dirty laundry, there would be no freshly washed laundry either!
And a bonus one about food:
- Life is like food. It tastes SO much better when your friends are around!
And that’s all! If you want more of my Random Ideas, just check out the page. Find out why I think lectures should have TWO lecturers, or learn about the time I was sold a hot chocolate with a dash of placebo effect…
###
My January Habit Change:
I’ve wanted to try meditation for a while. Thus, as I was thinking about my January Habit Change, I decided to try meditation. So here’s my mission:
From January 15th to February 13th (30 days), I will spend at least 10 minutes every day meditating.
I’m counting on you guys to keep me accountable!
 |
||
 |
|
|
{ 6 comments… read them below or add one }
The soup question is interesting !
You could just try to put oil in it so that the water won’t evaporate easily, then compare with a normal bowl
Of course the oily soup would probably taste different …
@Kevin:
That’s a pretty damn good idea! Maybe I’ll try that
I see my idea of the soup-cooling heat conduction vs. evaporation discussion contribution made it into a blog. =D
Well, wouldn’t, in theory, the conduction part of that experiment be conducted by having a topless container of some sort, to allow evaporation to take place, yet have the heat be conducted through the container? (The container would have to be able to hold ice or cold water within its walls, so I suppose setting the bowl inside a salad bowl of ice would work best to test the theory.) This is assuming that the evaporation-test part of the experiment (the bowl with the fan) is meant to test if there was something constantly blowing on the air above the bowl, which the bowl inside a salad bowl of ice would lack. So, if you understand what I just wrote, wouldn’t that be a practical test of the experiment?
Clyde Machine´s last blog ..Free Music (and Fire) For Everyone!
“Unfortunately, the small container would not only stop evaporation, it would stop hot air from leaving, which would keep the soup hot even if the Heat Conduction Soup Cooling Hypothesis supporters are right”
I’m pretty sure the same is true for the fan.
The oil idea sounds nice through. Assuming oil boils at a higher temperature than water which I really don’t know anything about.
@Clyde:
I’m not entirely sure what you mean. I was thinking of somehow testing two bowls that:
a) can evaporate and heat conduction takes place as normal
b) cannot evaporate and heat conduction takes place as normal
That would separate the effect of evaporation
. (The trouble with blowing on a bowl is that it not only replaces humid air with dry air, it also replaces the hot air with cold air.)
@Shadowart:
Yeah, pretty much.
@All:
One of my friends e-mailed me and suggested this: Take two bowls, fill them to the brim. Cover one with tinfoil that conducts heat well, so we stop evaporation but leave heat conduction intact. Leave the other bowl as normal, to let evaporation happen.
Pretty much the same as the oil idea, except slightly more controllable (as long as the tinfoil conducts heat really well).
I guess now I have to go off and buy two identical bowls, so I can actually do this experiment
Thanks for clearing it up, I see what you’re saying there.
Good luck on the experiment, I’ll check back and see if you get results on it, so I may be able to utilize the knowledge learned from it in the future.
Clyde Machine´s last blog ..Free Music (and Fire) For Everyone!