Question

When you drink a soft drink with the help of straw ,what forces the liquid up through the straw?

Answer 1

When we drink with a straw we suck the air and the air inside and it goes to our lungs and the pressure inside the straw decreases. Then the atmospheric pressure exerts force and the drink goes to the straw and then to our mouth

So basically it's the atmospheric pressure which forces the drink upwards.

Answer 2

Explanation:

When we suck the air out of the straw through our mouth, vacuum is created inside the straw. The atmospheric pressure (which is higher than the vacuum) outside, thus, pushes the liquid into the low pressure straw.