1. The atmosphere exerts pressure
|Step(s) to Follow||Expected Result|
1. Place hemispheres together and twist them back and forth to get a good seal.
2. Turn vacuum pump on and pump until sound indicates that air has been removed (pump will get very quiet)
3. Close the stopcock.
4. Remove the hose.
5. Replace the hose connection with the extra handle.
6. Ask for volunteers to attempt to separate the hemispheres
|The hemispheres will not be able to be separated.|
1. Open the stopcock.
2. Pull to separate the spheres.
|The hemispheres will easily separate.|
Be careful that the students are pulling and not attempting to slide the hemispheres past each other. If slid, it is possible to break the seal, allowing air into the hemispheres, thus rendering them easy to separate and defeating the purpose of the demo.