Here are a few experiments you can try to see the atmosphere! Drink something from it to be sure that it works. Now, make a small hole in it make sure the hole is large enough to see. Make sure the hole is above the level of the liquid in the glass. Does the straw still work? What happens if you cover the hole with your finger and then try to drink? When you suck on a straw that has a hole, you pull air through the hole, instead of removing air from the straw. The liquid stays put, unless you cover the hole.
Put the index card on top, making sure that the card completely covers the cup. This activity brought to you in partnership with Science Buddies. Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options. Discover World-Changing Science. Materials A package of plastic straws at least one dozen , preferably those with a bendable part Scissors Ruler Tape Drinking glass filled with water Level surface that can get wet or if not, something to protect it Sturdy chair or table on which to stand Preparation Have an adult help to cut two half-inch slits, across from one another, lengthwise in one end of a plastic straw.
These cuts will help you slip the end of one straw over another one. Prepare 10 more straws in a similar way until you have enough for a superlong mega-straw! You can also come back to these steps during the process in case you need more straws for your mega-straw.
Procedure Slip the cut end of a prepared straw over the end of an unprepared straw. Wrap the area where the straws overlap with tape so you have an airtight seal. Do not hurry; a good airtight seal will help you avoid trouble later. Why do you think a secure, airtight seal is essential for your mega-straw to function well? Hint: When you drink with a straw, you must remove air from it.
To test your extralong straw, put a glass of water on level ground. Be sure to place something down to protect your level surface or use one that can get. Now hold your straw vertically or close to vertically and try to drink with it. Does water reach your mouth?
If little or no liquid enters the straw, check the seal where you joined the straws. Is it airtight? If not, add tape or undo and redo this connection. If the seals at all joints seem airtight, check for holes in other areas of your mega-straw and seal them with tape. Play around with your first mega-straw.
Media Player Error Update your browser or Flash plugin. Decreasing Air Pressure With the straw just sitting in the glass, the pressure on the surface of the tea is the same all over, including on the little bit of surface inside the straw.
Why Do Straws Work? How Does A Barometer Work? Mercury When the meteorologist announces that the barometric pressure is twenty-nine inches of mercury, it means that the air pressure is capable of supporting a column of mercury twenty-nine inches high.
Become an Indiana Public Media supporter. If you formed a perfect vacuum within the straw, the pressure outside of the straw at sea level would be enough to push water to a total height of about At sea level, the air pressure is enough to support a column of water about thirty feet high.
This means that even if you could suck all the air out of a forty-foot straw, the water would not rise more than thirty feet.
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