The Science of a Very Long Straw

By Amy Cowen on July 30, 2015 8:30 AM

Explore atmospheric pressure by making and drinking from a very long straw in this week's science activity spotlight.

Three plastic straws taped end-to-end in a glass of water

Can a straw be too tall?

Can you use a really tall straw?

Your straw needs to be long enough to reach both the liquid you are drinking and your mouth, so it generally needs to be just a bit taller than the cup.

Most straws are about the same size. There are some bigger ones, of course, that match up to larger cups you might order in a store or restaurant. But whether they are plain or colored, bendy or straight, most straws are pretty similar in length. A straw that is not much taller than your cup probably helps reduce the chance of spilling your drink, but is there a maximum length a straw can be?

Straws are very effective at helping us draw liquid from a cup and up into our mouths, but the science of how this works might surprise you! Did you know that liquid is actually being pushed up into a straw because of changes in pressure that happen when you sip through the straw? In this week's hands-on family science activity, grab straws and tape and build a very long straw and see how long a straw can be and still work. What will give out first, the straw or your ability to draw liquid up and through it?

You may have built marble runs or roller coasters before, but have you ever tried to set a family record for longest straw? Give it a try, and have fun talking about the science at the same time!

Find directions for this experiment in the following free STEM activity: