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ACTIVITY GUIDE
BALL AND RING APPARATUS
HYPOTHESIZE HOW A BRASS BALL WILL EXPAND WHEN HEATED.
Materials provided: Ball and Ring
Materials needed: Propane torch or another heating source, gas lighter, a gauze pad with ceramic center
Procedures: Observe the Ball apparatus. Slide the Ball through the opening of the Ring. Remove the Ball apparatus from the Ring. Turn on your propane torch or heating element carefully.
SAFETY FIRST : If you are using a propane torch, make sure the nozzle of the torch is away from your body before lighting it. Always use the handles of the apparatus when holding it.
After lighting the propane torch, place the Ball into the center of the flame for one minute.
Pick up the Ring with your other hand. Carefully place the Ball into the center of the Ring. Does the Ball pass through the ring? Why do you think it does or doesn't pass through the ring? Place the Ball and Ring in the center of the ceramic gauze pad. Allow it to cool for a few minutes. Carefully place the Ball into the center of the Ring again. Does the Ball pass through the ring this time? Repeat the activity again by heating the Ball. Carefully place the Ball into the center of the Ring. Does the Ball go through the center of the ring this time? What do you think happened to the Ball when it was heated? Place the Ball and Ring on the center of the ceramic gauze pad after completing the investigation. Allow the Ball and Ring to cool for a few minutes before testing it again.
Analysis: The Ball and Ring Apparatus is a scientific instrument used to demonstrate expansion and contraction of solids by Conduction. When you slide the Ball through the opening of the Ring, the Ball is slightly smaller than the Ring and possesses potential energy. After heating the Ball, the metal expanded and now has kinetic energy. The addition of heat energy causes the molecules of brass to vibrate and expand. When the Ball is cooled, the thermal energy the Ball has passes into air surrounding the Ball. The Ball again has potential energy and returns to its original shape. Generally, metals are the best conductors of heat. The ability of a given material to transfer heat energy depends on the area and length of the conductor.
Critical Thinking: What happens to a bridge or a roadway on a very warm day? What happens to a bridge or a roadway on a very cold day