Jolly's Photometer Build to Order Bell-in-vacuum jar with a 4-6V

Bell-in-vacuum jar with a 4-6V electric bell suspended on rubber cord inside a 22 by 15cm glass chamber

Solid glass friction rod that develops a positive electrostatic charge when rubbed with silk or wool

these two-part polypropylene Buchner funnels fit 11-12

5 ratio favoring intense convergence demos and short-throw real-image formation work

letting students drive the lamp directly or send the slow AC output to a meter or oscilloscope

Jolly's Photometer Build to Order Bell-in-vacuum jar with a 4-6VBrightness comparing Jolly's photometer using a translucent paraffin disc method, the balanced position locating the photometric midpoint between two unequal light sources.