Using a vacuum pump to boil cold water?

Question

for a school project, i need to boil cold water using a vacuum pump. I did some research, but i still didn't find what i needed. I need to know what kind of pump i need for this, and where i can get one for cheap, since i will only use it for this project. if you know how to actually use it, you can throw that in as well. thanks!

Answer 1

Have you asked at your school? Most have items like vacuum pumps for these projects.

Good vacuum pumps can be found at stores selling supplies for refrigeration repairs, but they are not cheap. $150 to $400 range.

You can get a very inexpensive plastic vacuum pump that works on the venturi principle, and needs a constant supply of running water (sink faucet, etc.). Order from laboratory supplies companies. Cost about $5 to $10. Does not pull a vacuum very fast, but will produce a fairly high vacuum, time required relates to the size of the apparatus.

To use, connect pump to running water supply, connect tubing from the side inlet on the body of the pump to the inlet of your container of water. Water could be in a flask with a single hole cork with a short piece of glass tubing in the hole, connect the flexible tubing to pump. Turn on water supply to pump, and wait until the water in the flask starts to boil. Boiling occurrs when the pressure on the surface of the water is equal to the energy or pressure within the liquid, called the vapor pressure. Water will boil at any temperature above freezing if the surface pressure is low enough. The warmer the water, the sooner it will boil, so warming the water to a temperature near boiling will make the project work faster. You could show how the initial temperature of the water relates to the strength of the vacuum needed to make it boil. You could get an inexpensive vacuum gauge at an auto parts store (manifold vacuum and fuel pressure gauge). They should also have a T fitting so you can connect the gauge to the project. You can mount the gauge anywhere in the tubing connecting the vacuum pump to the flask of water. The tubing needs to be thick enough so it won't collapse when the vacuum is strong. You can get good inexpensive clear tubing at a hardware store. The hotter the water, the less vacuum is needed. After freezing, water will continue to evaporate by a process called sublimation, which means passing from the solid state to the gas state without passing through a liquid phase. If you have noticed that ice cubes in freezer trays slowly disappear, you have observed sublimation. The same process is used in freeze drying of fruits and vegetables. Hanging clothes out to dry when temperature is below freezing works fine. First the clothes freeze stiff, then they dry.

I wish drip would explain how to use a bicycle pump to pull a vacuum. If you reversed the cup and incorporated a check valve, you might produce a slight vacuum. How about it drip? Put your money where your mouth is, or engage brain before putting keyboard in gear.

Answer 2

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Answer 3

I'm not telling you it all but you can take an A.C vacuum pump and it will lower the boiling point of the water where it will boil at only 65 to 75 degrees Ferlinghetti

Answer 4

You can get a cheap hand powered pump at the auto store. They use them to vacuum airconditioner systems and check for leaks in vacuum operated controls.

Answer 5

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Answer 6

If you have a compressor you can connect to the inlet which draws a vacuum, remember to open the outlet side. You can use a hand pump by connecting to inlet side.

Answer 7

The vacuum must be on the go.

Answer 8

I'm not telling you how to build the whole thing, but a bicycle pump works just fine.

;)

HTH