Keeping cool

When I first moved here, I thought people were doing it to keep dirt from being tracked into the house. But I've learned since then.

Ridiculous. Great way to increase the humidity though.

Ok which one of us is the grinning guy in the middle?

This was originally done because all the streets were dirt, and it kept the ground slightly moist, and decrease the amount of dust in the air.

But for some reason, Japanese still do it even though the roads are paved, only now they convince themselves it somehow lowers the temperature.

Kind of like that song "Tradition" from "Fiddler on the Roof"

But for some reason, Japanese still do it even though the roads are paved, only now they convince themselves it somehow lowers the temperature.

Water can hold more heat per volume than most substances, and definitely more than asphalt. When water is put on asphalt, as long as it is at a lower temperature than the asphalt, it will absorb some of the heat. So the laws of physics would basically prove that putting water on the asphalt does indeed lower its temperature.

So the laws of physics would basically prove that putting water on the asphalt does indeed lower its temperature.

And this would be useful if we were all walking barefoot around the city.

I never claimed it to be useful, I just pointed out that the logic is actually sound.

I never claimed it to be useful, I just pointed out that the logic is actually sound.

Not exactly. You demonstrated that the laws of physics says the water decreases the temperature. You can only claim that it's logical of the decrease in temperature is actually noticeable (besides the placebo effect) by people who take such action. For example:

1) How MUCH does it decrease the temperature by?

2) How LONG does it lower the temperature for?

3) What is the human energy cost to decrease the temperature for that amount, and that duration?

I have ZERO issue with people doing illogical things based solely on tradition, that is the stuff of human civilization.

But please don't try and convince anybody that ANY tradition has any "logic" to it.

Of course it's logical.

Turning liquid water into vapour requires energy.

The energy here is supplied in the form of heat from the asphalt.

Hence the more the water is converted to vapour, the cooler the asphalt will become.

Simples.

Ooh steady gaijinfo, many traditions and cultural practices have logic behind them, although they can be lost in the mists of time. This evaporative cooling method removes heat from the pavement in the same way sweat removes heat from the human body. There's a lot of large scale air conditioning plant that works in the same way.

We keep hearing about the shortage of fresh water in Japan, so this seems to be a waste of water for nothing more than tradition. I agree with you gaijinfo. Far too much waste and not enough conservation in a nation so short of resources.

We keep hearing about the shortage of fresh water in Japan

I refuse to believe Japan has a water shortage problem after the rainy season we've just gone through.

You can only claim that it's logical of the decrease in temperature is actually noticeable

Um, no. I already showed the logic of it. The laws of physics show that heat will flow from a hotter item to a cooler item, until they are balanced in temperature. So if the water is cooler than the asphalt, then the asphalt will cool down and the water will warm up, until they are the same temperature.

Now you can argue that the change in temperature is not enough to make a difference to the overall temperature of an area, and you may or may not be right. But that doesn't change the underlying physics of the matter.

But please don't try and convince anybody that ANY tradition has any "logic" to it.

I just did, for a second time.