Description

Show your students how sound needs a medium to travel through with the Frey Scientic Vacuum Bell Jar Demo. Remove air from the jar. . .and listen as sound radiating from the bell gradually fades to silence! Kit includes a glass bell jar (6-1/2 D x 9-3/4 inches and 5 pounds of weight), vacuum base plate (8 D x 1-1/2 inches), gasket, hose, and battery-operated ringer electric bell (2 AA batteries sold separately). Bell jar has a vacuum pressure of less than/equal to --.06 MpA; rating of 3 VDC; withstands pressures from 14 to 104 degrees Fahrenheit (-10 to 40 degrres Celsius) at 85 percent of humidity. Full functionality of demo requires a vaccum pump (sold separately) to demonstrate the release of air.