The question pretty much sums it up. How TF is the asphalt 20-40° hotter than the air when it’s super hot?
In: 531
Everything soaks up heat like a sponge. Everything.
Air’s “heat sponge” sucks, so much so that air is usually used to keep heat *away* from other things. It just doesn’t hold very much of it, and doesn’t hold on to it for long.
Asphalt, on the other hand, has an excellent heat sponge. It soaks up *tons* (not an actual unit of heat) of heat, and it likes to hold on to it for a while.
So on a bright sunny day, the air is struggling to hold onto any thermal energy the sun puts out. It’ll get up to 80 or 90 F, but that’s it. Asphalt is drinking up all that thermal energy, holding on to it, and increasing in temperature way more than the air. So at noon on a sunny day, your air is warm and that pavement is scorching.
Have you never stood in the sun and felt your skin getting hot? It’s that.
Concrete is a better conductor of heat than air, which is considered an insulator. When the sun beats down on concrete, the energy transfer is more efficient and it holds onto it longer. Air is a terrible medium of heat transfer.
Do they not teach basic physics in high school anymore?
The increase in the earth’s temperature is directly correlated to the increase in usage of concrete. So does that mean it’s the cause of global warming 🤔
Yes this post has a little bit of tongue and cheek. Global warming also has am inverse relationship with the population of pirates…
Think of the air like a bowl and the asphalt like a bucket. Imagine you are filling both of them with water (heat). The bucket can hold a lot of water in it while the bowl can only hold a little bit of water. When you weigh each of them at their maximum capacity, the bucket will have more water than the bowl. It’s that simple.
One time I was painting a mural when it was 116degrees outside…. I felt strange when walking, like I was sliding in my shoes…. I look down and the soles of my tennis shoes were melted flat and I was in fact sliding in my shoes…
The energy the sun sends to the ground is more than the ground can reflect at the same time, so the ground get hotter and hotter over the day.
Air is transparent and did not absorb so much energy.
It’s been in the 80s to 90s around the clock for some days where I’m at. Today I had to go out towards the end of a sudden thunderstorm. When I crossed a street, water rushing to the nearest catch basin came up over my ankles. It was nearly as warm as bath water.
After the storm passed, the neighborhood felt so much cooler. It made me realize just how much heat is absorbed by asphalt, and how much heat is carried away by a rain.
So, the reason why things get hot is the sun. Not the air.
The air, in fact, is transparent, so it’s that one thing that doesn’t get hot in the sun. Sunlight passes right through it.
Air gets hot by being near objects that are hotter than it.
Like concrete.
That’s why you need to wear some layers if you go in altitude. But air gets hot in any flat space. It gets hot from being near the hot ground, which gets hot from the sun.
So, ground in the sun will always be hotter than the air.
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