why is petrol cold?

Question

petrol feels cold when touched (low temperature).Who can tell the scientific reason why it is so?Folks,lets share. Thanks.

Answer 1

If you had a little pool of petrol in the palm of your hand it would feel colder than water because it evapourates quicker and for something to evapourate it needs energy.

In this example the energy it needs would be heat energy drawn from your hand, it's something called the Latent Heat of Evapouration (or Vapourisation).

Also, petrol is more thermally conductive than water which means it can conduct heat away from your skin faster than water. The more thermally conductive something is the colder it feels - metal feels colder than plastic which feels colder then wood which feels colder then fabric etc.

You'll notice the same effect with other solvents inclusing surgical spirit, methylated spirits and alcohol.

Answer 2

Rule of thumb: "Evaporation produces cooling".

All liquids evaporate, which means that fast molecules at it's surface escape into the air. Since the slow molecules are left behind, and temperature is a measure of the average speed of the molecules, it decreases.

Petrol has a low boiling point, so it evaporates faster than most liquids, and therefore it feels cooler than most liquids.

Answer 3

gas ,things that evaporate alwaysfeel cold because the evaporation takes the heat along with it

Answer 4

you'd be cold if you lived in a petrol tanker.

Answer 5

it evaporates....so therefore it feels cold