## What is the longest straw you can use to drink water?

approximately 10.3 m

## How long could a straw be?

~10.3 meters is the theoretical limit – that’s for perfect vacuum. That’s pretty long. Still, humans can’t make perfect vacuum using their mouths, so practically even a 6 meter long straw would make you sweat hard.

## Can you drink water through a long straw from a platform 40 feet?

NO. (Stated as simply as possible) it’s atmospheric pressure that pushes liquid up the ‘straw. ‘ If we apply a perfect vacuum at the top end of the ‘straw,’ atmospheric pressure (14.7 psi) can only push the water column up 33. 9 feet.

## Why does water stay in a straw when you hold the top?

Thanks for your help! Answer 1: What’s going on is that the water in the straw is pushed into the straw by the air pressure outside of the straw. As long as the pressure outside is able to overcome the force of gravity, the liquid will stay in the straw.

## Why does a straw with a hole in it not work properly?

The air pressure is the same inside and out. When you drink through the straw, you seal your lips against the straw and then you use your lungs and mouth to reduce the air pressure in your mouth. You do this by expanding your mouth or lungs. This also allows air to enter, preventing the straw from working properly.

## How does drinking from a straw work?

When you drink from a straw, you create a little space of low pressure inside your mouth and in the top of the straw. Then the air outside the straw pushes down on the surface of the drink and forces the liquid up through the straw and into your mouth.

## How does the straw trick work?

Sealing the top of a straw with your finger stops air entering and exerting a downward force on the liquid, leaving only the upwards force of air pressure from below. This upwards force is stronger than the force of gravity pulling down on the liquid.

## How do you close one end of a straw?

Tear the wrapping off half of the straw, so that one end is exposed. Put the exposed end in your mouth, take aim, and blow! The wrapper shoots off the other end, like a dart from a blowgun. (Do not do this at close range, and do not aim at anyone’s face, please.)

## Why does water not fall out of a straw when it is closed on one end?

This is because the atmosphere exerted a pressure upwards from the bottom to prevent the water from falling (the headspace above the water has some small downwards pressure that is minimized by the incompressibility of water). The net force is zero, so the water doesn’t move.

## Why does fluid not flow out of the straw if we submerge it in water and hold your thumb on the top?

The fluid outside the straw is comparatively at high pressure (atmospheric pressure) and thus it starts pushing the fluid inside the straw upwards. Now, if you close the upper end of straw with your thumb, you create a seal that doesn’t allow air or fluid to enter into the straw through that end.

## What is it called when water goes up a straw when placed in water?

This is due to what is called the capillary action. It is caused by the surface tension of the liquid and the adhesive force between the liquid and the container which act to lift the liquid up, against the force of gravity.

## Why does water get stuck in a straw?

Thus, the weight of the water causes a lower pressure at the top of the straw. The differential pressure between the air trapped at the top of the straw and the atmospheric pressure outside (and at the bottom) of the straw then keeps the water in place.

## What causes the liquid to rise in the straw?

The atmosphere pushes the liquid in the glass up into the straw. Since the atmosphere is also pushing down on the liquid in the straw, the liquid rises, just until the force of the atmosphere on the liquid inside the straw exactly balances the force of the atmosphere inside the glass.

## Is there an upper limit to how long a straw can theoretically be and still work as a drinking straw?

Yes there is a limit. A straw’s length depends on the local air pressure and the fluid density to cause flow. If you have a perfect vacuum in your mouth, a vertical straw at sea level could be as long as about 33 ft and still work.

## How do you make a super long straw?

First, just pinch the tip of a straw, as shown in the 1st picture, then just put the tip you are pinching into another straw. Next, roll a peice of duct tape around this joining and you are done with this section. Just repeat this step untill all the straws are attached into 1 big straw.

## Do straws work in space?

You could put an industrial vacuum pump on the straw and it won’t get a drop (not unless you count water vapor). It can’t, because there is no such force as “suction,” only atmospheric pressure rushing in to fill the void. On the moon (outside a pressurized habitat) there is no air pressure, so straws don’t work.

## Do pumps work in space?

– Heat pumps designed for NASA’s International Space Station (ISS) and the new Orion lunar crew exploration vehicle are not pie in the sky. They are real, functioning HVAC units that must actually work in outer space.

## Can you drink from a straw on the moon?

No. What forces the drink up through the straw is air pressure on the surface of the drink. Because the pressure inside the straw is less than the air pressure outside, the liquid is forced up. On the Moon, no air, so no air pressure.