Table of Thermodynamics Demonstration

Thermodynamics Equipment List

Lecture Demonstrations

Large Ball and Ring Stand, 4A30.20

Topic and Concept:

Location:

BallStand04-400.jpg

Description:

This demonstration has a ball and ring with stand. It demonstrates the thermal expansion of the material by heating the ball.

Equipment

Location

ID Number

A ring with stand and a ball with hanger

TD, A3, Shelf #1

4A30.20

Burner with an iron ring tripod and wire net screen

location

NA

An iron ring tripod and a screen

location

NA

Safety grove and glasses

location

NA

Red and white gas carts

Rooms 2103, 2241, (and 2223 upon request)

Important Setup Notes:

Setup and Procedure:

  1. To light the burner, connect the attached gas hose to the gas out (red panel) on the red and white gas cart.

  2. Open the gas valve.
  3. Light a match and bring it near the top of the burner.
  4. The flame will ignite the gas. Adjust the flame height accordingly by adjusting the valve.
  5. Show that the ball can get through the ring.
  6. Put the lit burner beneath the tall ring stand with the screen on the top.
  7. Lower the ball onto the screen using the attached hook. It will take about a minute for the ball to heat up enough to not fit through the ring
  8. Take the ball off the stand and try to lower the ball through the ring.
  9. If the ball fits through the ring, repeat steps 7 & 8. Otherwise, let the ball rest on the ring. As it cools, it will eventually shrink enough to drop through the ring.

Cautions, Warnings, or Safety Concerns:

Discussion:

When the ball is heated, its dimensions increase while maintaining their relative proportions. Heating causes the molecular bonds to lengthen, which causes the material to expand. This is considered a 2D expansion since the quantity of importance for the ball to fit through the ring is the cross sectional area. The expansion can be described by ΔA/A = αA*ΔT = αL2*ΔT where A is the area at temperature Ti, ΔA is the change in area when the material is at temperature Tf, ΔT is Tf - Ti, and α is the coefficient of thermal expansion which depends on the material. See references below for more information.

4A30-20_01a.jpg

4A30-20_02a.jpg

BallStand03-250.jpg

BallStand04-250.jpg

BallStand05-250.jpg

BallStand06-250.jpg

Videos:

References:

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fw: LBRS (last edited 2013-07-17 18:53:51 by srnarf)