B6D7E1 – The Principles of expansion and contraction of matter
Name: Lim Li Fern (14)
Identification Card No.: 990412-11-5206
Subject teacher: Puan Norlida
Heat does to matter is changes it state. There is something more subtle though that can cause big problems. Look at this devise. When you heat both this ball and the ring the ring expands like a long bar of metal. The ball expands less so when they are heated the ball fits through the ring. You may want to look for these and try this demo as many of you probably have these.
Another neat tool to show the expansion of metals is this bimetal bar. It is made with one metal on one side and another metal on the other side. One metal expands more rapidly so the bar twists when heated.
This affects things in the real world drastically. If this is not considered when building something we can end up with a road buckling. Engineers then plan for the expansion and contraction due to heat.
In a pipe we may see special parts like this or this so that the pipe can expand in length without breaking.
Behaviour of matter - Expansion and contractioncontraction
Substances expand or get bigger when they are heated up. They contractor get smaller when they are cooled down. This property can be useful. * Thermometers work because the liquid inside them expands and rises up the tube when it gets hotter. * Metal parts can be fitted together without welding using shrink fitting. The animation shows how this works. Expansion and contraction in metal
The rod is too big to fit through the hole.
The rod is cooled, causing it to contract.
The rod fits in the hole. When warmed, it expands to fit tightly.
All matter is affected by heating and cooling. With a very few exceptions, when any matter is heated, it will expand. When it is cooled, it will contract.
Observing a Gas Expand When Heated
Procedure: Place the neck of the balloon over the mouth of the bottle. Put about 6 cm (2 in) of water in the bottom of the pot and place the bottle and balloon in the pot. Heat the water slowly over the stove. You do not need to heat the water to boiling. What happens to the balloon?
Remove the bottle and allow it to cool. What happens to the balloon now?
What Happened: When the air inside the bottle was heated by the hot water, it expanded. As the air expanded, some was pushed into the balloon causing it to expand slightly. When the air inside the bottle cooled, it contracted and the balloon shrank.
Observing a Gas Contract When Cooled
Just as you saw a gas expand when heated, you can see how it contracts when cooled using the same material as in the last experiment.
Procedure: Place a couple of inches of water in the bottom of the pot and place the bottle in the pot. Heat the water to almost boiling. Then, using the oven mitts, remove the bottle and quickly place the balloon over the neck. Allow the bottle to cool and observe the balloon as the bottle cools.
What Happened: As the air inside the bottle cooled, it contracted. This caused the balloon to be drawn into the bottle.
Observing a Liquid Expand When Heated
Procedure: Put a little food coloring or a pinch of coffee or fruit drink mix in the bottle. Fill the bottle completely with cool tap water. Place a couple of inches of water in the bottom of the pot and carefully place the bottle in the pot, being careful not to spill any of the water. Slowly heat the water in the pot almost to boiling and observe what happens to the water in the bottle.
What Happened: As the water inside the bottle was warmed, it began to expand. The bottle could no longer hold all of the water and the water began to “bulge” from the top. Some may have even spilled out.
Observing a Liquid Contract When Cooled
Procedure: Fill the bottle completely to the top with hot tap water. Try to get as few bubbles in the water as...