Science · 6 pages · 12 min
Why a straw can lift a drink
You lower the pressure in the straw, and the air on the drink pushes it up.
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From the opening
A straw lifts a drink because sucking lowers the pressure above the liquid inside the straw. Atmospheric pressure on the free surface in the cup is then higher, and that imbalance pushes the drink up the tube. The opening covers lower pressure inside the straw, atmosphere pushing on the cup, and why a sealed jar stops the trick.
The rest of the brief — the later sections and the reading notes — opens after Stripe confirms payment.
Inside
- Lower pressure inside the straw
- Atmosphere pushing on the cup
- Why a sealed jar stops the trick
- The same idea in a lift pump
- Where the idea stops applying
- A distinction worth keeping
Sources
- Atmospheric pressure on a free liquid surface
- The water barometer as the limit of a lifted column