Does black pavement atract or reflect heat?

Question

My daughter has to do a project, and we can seem to find any information about it. The statement is "Black colored streets get hotter than stone colored streets, causing the earth's temperature to rise. Continuing to make black colored streets contributes to global warming."

She has to either prove or disprove the statement. Any opinions?

Answer 1

Asphalt streets cause a phenomenon in cities called "urban heat islands".  Temperatures in cities with allot of asphalt and pavement tend to much higher than the surrounding suburbs.

Black colored materials absorb heat whereas lighter colored materials reflect heat and therefore stay cooler.

The link below should state your case.  Good Luck!!

Answer 2

BLACK WILL MEAN A VERY HOT PAVEMENT

and very hot air above it

that is why you do not see many black pavements

light colors reflect and silver reflects the most

Answer 3

The source below discusses albedo which is basically a measure of the energy reflected by a surface.  Like ENGINEER above indicated, high albedo surfaces reflect more energy (snow, light colored sand) than darker surfaces (ocean, pavement, even forests).  So, technically, darker surfaces will tend to store more energy instead of reflecting it back into space.

However, when you look at the ocean surface with an albedo of approx 3.5% and how vast it is, I don't believe changing to light colored streets would have much impact on the earth's temperature.  Locally, in large cities, it could potentially reduce the heat-island effect some but the overall effect would probably not be enough to measure on a global scale. If you look at the extra cost of using stones or concrete to produce all streets, there would probably be more cost-effective ways to impact the earth's temperature.

Good luck

Answer 4

The statement is basically true.

The darker the color of an object the more light is absorbs. That is why it is dark. The lighter the color of an object the more light it reflects. That is why it is light colored. Things look dark because less light bounces off of them and things look light because more light bounces off of them.

The fact that something is darker proves that it is absorbing more light.

Light from the sun is what warms the Earth. You can take that to be a given fact.

If something like a street is hotter then it will warm its surroundings up more than a cooler street. You can take that as a given fact as well.

If the surroundings are hotter then that is a contribution to global warming. You can take that as a given fact too.

So putting all of this together you get.

A dark colored street, simply because it is dark colored, will absorb more of the Sun's light and therefore will get hotter than a light colored street. A hotter street will heat it's surroundings more than a cooler street. If the surroundings are hotter then that is a contribution to global warming. Therefore dark colored streets make more of a contribution to global warming than light colored streets.

I hope that helps.