Why Does A Tarmac Road Seem To Be Wet From A Distance, On A Hot Day?

Gloria Acen,

Rima Primary School, Lira

The ‘water’ you see in the road on a hot day is caused by what scientists call a “mirage”. When the sun heats the ground, the air just above the road becomes hotter and, therefore, becomes less dense than the air higher up forms a mirage. The mirage is caused by the refraction (bending) of light rays due to the differing temperatures of the air above the road.