World's Longest Straw: How Long Can a Straw Actually Be?

TL;DR

A straw can theoretically be up to about 10.3 meters long, but only if you could create a perfect vacuum in your mouth. Two friends tested this by taping drinking straws into a 1-meter length, then successfully drinking from 6 meters of plastic tubing off a balcony, and finally attempting 10.5 meters at Tamarama Beach, where they lifted the liquid only about 7 meters. Read on to see why atmospheric pressure sets the hard limit.

Transcript

Hey Nige, can you get me another coke? Nah, I'm good, thanks. It's just downstairs. Nah, the tennis is on. You come to my house to watch the tennis and you're not even going to get me another coke? Yeah, it's the tiebreaker. Relax. You know what I wish we had? Like a really long straw so we don't even have to go downstairs to the kitchen. That wou... Read More

Key Insights

• 🍓 Long straws can be made by taping together multiple shorter straws.
• 🤑 Straws work based on the difference in pressure between the mouth and the atmosphere.
• 🏋️ The maximum height of liquid that can be lifted is determined by the pressure difference and the weight of the liquid.

Questions & Answers

Q: How long can a straw actually be?

The theoretical maximum is about 10.3 meters, but that relies on being able to create a perfect vacuum, which is impossible for a person. In practice, the friends could only lift the liquid roughly 7 meters even with 10.5 meters of tubing.

Q: What is the longest straw the friends successfully drank from?

Nigel successfully sucked liquid all the way up 6 meters of plastic tubing lowered off a balcony. They had earlier started by taping drinking straws together into a 1-meter length as a first test.

Q: How does a straw work?

A straw works because of the difference in pressure between the atmospheric pressure and the lower pressure you create in your mouth. When you open your lungs and pull your diaphragm down, you reduce the pressure in your mouth, and atmospheric pressure pushes the liquid up the straw and into you.

Q: What determines the maximum height liquid can be lifted with a straw?

It depends on the pressure difference created by sucking and the weight of the liquid, which is set by its volume, density, and the gravitational field strength. Based on these calculations, the maximum height works out to about 10.3 meters for water.

Q: Why couldn't they drink from the full 10.3-meter straw?

Reaching the theoretical maximum requires a perfect vacuum, which a person cannot create by sucking. When Nigel attempted 10.5 meters of tubing at Tamarama Beach, the liquid got stuck and only rose about 7 meters before it stopped.

Q: Does the diameter of the straw affect how hard it is to drink?

Yes. Nigel's tube was about 3 mil in diameter while the other tube was about 5 mil, and the thicker 5 mil tube was noticeably tougher to drink through. One person failed at the 5 mm diameter before Quan managed to succeed with it.

Q: Why is atmospheric pressure measured with mercury instead of water?

Atmospheric pressure pushes mercury up a tube with a vacuum at the other end by 760 millimeters, about 0.76 of a meter. If you used water instead, you would need a barometer roughly 10 meters long, which is why mercury was used (and pressure is now measured in kilopascals).

Summary & Key Takeaways

• The friends discuss the idea of a really long straw to avoid going downstairs for drinks and decide to test its feasibility.

• They test different lengths of straws, starting from 1 meter and eventually reaching 6 meters, successfully drinking from a straw 6 meters long.

• They explain the science behind how straws work and calculate the maximum height of liquid that can be lifted using a straw, which is approximately 10.3 meters.