When you suck through a soda straw into a drink as shown in the illustration below, what causes the drink to rise into your mouth: the muscles of your lungs and cheeks or the weight of the atmosphere?
A)the muscles of your lungs
B)the weight of the atmosphere
C)Both factors are equally accountable for the soda's rising into your mouth.
D)Actually, neither the muscles of your lungs nor the weight of the atmosphere is the reason for the soda's rising into your mouth.

Question

When you suck through a soda straw into a drink as shown in the illustration below, what causes the drink to rise into your mouth: the muscles of your lungs and cheeks or the weight of the atmosphere? 
A)the muscles of your lungs 
B)the weight of the atmosphere 
C)Both factors are equally accountable for the soda's rising into your mouth. 
D)Actually, neither the muscles of your lungs nor the weight of the atmosphere is the reason for the soda's rising into your mouth.

Quizplus · Accepted Answer

The weight of the atmosphere is responsible for pushing the drink up the straw and into your mouth. As you suck on the straw, you create a low-pressure zone, which decreases the air pressure within the straw. The atmospheric pressure outside the straw then pushes the drink up and into the straw, and ultimately into your mouth. The muscles of your lungs and cheeks play a role in creating the suction, but they do not directly cause the drink to rise into your mouth.

When You Suck Through a Soda Straw into a Drink