Low Cost Category

2002 AAPT Apparatus Competition, Boise State University

Name: Alexander Sapozhnikov Roman Ya. Kezerashvili

Address: Physics Department New York City Technical College

Brooklyn College The City University of New York

2900 Bedford Avenue 300 Jay Street

Brooklyn, NY 11210 Brooklyn, NY 11201

Phone: 718-951-5034 718-260-5277

Fax: 718-951-4407

E-mail: alexs@brooklyn.cuny.edu rkezerashvili@nyctc.cuny.edu

Apparatus Title: Apparatus for Demonstration of Apparent Weightlessness

Abstract (40-50 words)

The apparent weightlessness occurs for falling objects. For demonstration of this phenomenon a scale with light bulb is used. When the scale doesn't load, it shows zero and the bulb doesn't light. The loaded scale shows the weight and the bulb lights. While the loaded scale is falling, students can see that it shows zero and the bulb is flushing, as if the scale does not have any load.

Equipment required to construct apparatus: a demonstration scale, a switch, a battery holder, a lamp screw socket, a support, and two clamps

Item Source / Store Part Number Cost

Demonstration Spring Scale Sargent Welch WLS-3775-300 $25.00

Switch Newark 35C2237 $1.53

Battery Holder Newark 18C1021 $0.73

Lamp Screw Socket Newark 96F8039 $1.45

Two Right Angle Clamps Sargent Welch CP12241 $10.15x2=$20.30

Total cost $63

Description:

An electric circuit with batteries, a switch, and an electric bulb (2) are mounted on the demonstration scale (1). There are two parallel tubings on the scale. The apparatus is assembled on a support stand 1.5 m high (3). Two strings (4) are attached with pare of clamps and rods (5) on it. The scale with a load (6) can freely slide along the two strings. Rubber corks and two springs (7) amortize the hit of the scale.

While the loaded scale is released from the top part of the support and is freely falling, the bulb flashes and the scale shows zero that demonstrates the phenomenon of apparent weightlessness.

Sketch of the apparatus