As a member of the science education industry, often teachers ask what is the best and most vivid experiments they can do in their classrooms to teach physics with a high vacuum pump. Over the past ten years, these five have become my favorite physics demonstrations demonstrating properties of matter and high vacuum physics.
Of course, to get started, you’ll need a vacuum pump, high vacuum tubing with tubing clamps, a vacuum pump plate, and a good quality bell jar. It also doesn’t hurt to have some vacuum grease or petroleum jelly handy to lubricate and seal between the bell jar and the pump plate. And now onto the top five:
5. Shaving Cream Expansion – Put a little dab (technical term) of shaving cream inside your bell jar (which is then sealed onto the pump plate), turn the pump on and watch the molecules spread themselves out and the Shaving Cream grows! Be careful not to let it run too much where you pull the Creme into the vacuum pump though!
4. Grow a Balloon – place a balloon, filled a little bit and tied off inside your bell jar and turn the pump on. Students will be curious as to why the balloon expanded while the air is pulled from the chamber.
3. Springtime (Easter) Peep Monster – place one of those terribly unhealthy, yet tasty, sugar coated marshmallows, THE PEEP, inside your bell jar. Turn on the pump and watch your baby peep turn into a Stay Puft Marshmallow Man peep!
2. Did you hear a bell ringing? – place an electric bell or kitchen timer inside your chamber and turn on the pump. Make sure the bell is turned on! As the air molecules are pulled from the chamber, the sound will slowly disappear until it is gone! Great way to explain to students why an astronaut would never be heard if he were to start screaming while in outer space.
1. Cool Boiling Water – My all time favorite. It is absolutely critical that your pump is a “high vacuum” pump and not just a vacuum pump. You’ll need to pull a much higher vacuum than the 25″ of mercury some pumps offer to do this. Place a plastic bottle or petri dish in the chamber filled about half way up with water. Demonstrate to your students that the water is at room temperature and not hot to the touch. Put it in the vacuum chamber, turn on the pump, and in no time you’ll have room temperature water simmering at a rapid boil. What better way to explain the effects on vapor points in different atmospheric pressure?
You can do a quick search on the internet and find all of these supplies from virtually every science education dealer. One tip, keep an eye on your vacuum pump oil level and drain and change any contaminated oil. Be sure to use “High Vacuum Pump Oil” as standard vacuum oil or other “home remedy” solutions (See: motor oil, vegetable oil, etc) will not allow the pump to continue operating properly!