33. Heat

The ball and ring apparatus shown is used to study the effect of heat on metals.

The source of heat is usually a Bunsen flame.

Which one of the following statements is INCORRECT?

• When the ball is heated strongly, it can pass through the ring.

• If only the ring is heated strongly, the cold ball will pass through the heated ring.

• When the ball is heated strongly and then allowed to cool, it will pass through the ring.

• If both the ball and ring are placed in ice-cold water, it is possible for the ball to pass through the ring.

The round bottomed flask is placed in a large beaker of water, and it is filled with a liquid.

After heating the flask, what position on the glass tube would you expect the liquid to be?

• A

• B

• C

In winter, when the temperature goes below 0 ºC, water pipes sometimes burst. This is because

• below 0 ºC, the water changes to ice which expands and bursts the pipe.
• the pipe contracts faster than the water in it.
• the pipe expands and bursts when the temperature goes below 0 ºC.
• when the temperature rises above 0 ºC again, the water expands and bursts the pipes.

When the flask was heated, air inside expanded.

When the flask was allowed to cool, the water rose up the glass tubing.

Why did this happen?

• The air inside the flask contracted.

• Liquids expand when cooled

• The water expanded and rose up the glass tubing.

• The volume of the air in the flask increased.

When the temperature of a copper rod is lowered, its length

• decreases slightly
• stays the same
• increases slightly

The apparatus shown in the diagram was used to investigate the expansion and contraction of a gas.

What is observed when the flask is heated?

• Bubbles pass from the glass tubing into the water.

• The level of water in the basin rises.

• The level of water rises up the glass tube.

• The water in the basin begins to get very hot.

A bimetallic strip consisting of brass and steel riveted together is placed in the flame of a Bunsen burner.

The strip is seen to bend because

• the two metals expand at different rates.

• only one of the metals expands.

• the two metals expand at the same rate.

• the bunsen flame causes one of the metals to melt.

In the experiment shown in the diagram a hair dryer heats air in a flask. Bubbles are seen to pass out of the glass tube.

What does this experiment demonstrate?

• Gases expand when heated.

• Liquids expand when heated.

• Gases contract when heated.

• Water is sucked into the flask.

Which one of the following is TRUE when particles of matter are heated?

• They gain energy, will move faster and get further apart.

• They lose energy, will move faster and get further apart.

• They lose energy, will move slower and get closer together.

• They gain energy, will move slower and get closer together.

In winter, when the temperature goes below 0 ºC, lakes are liable to freeze.

In which one of the following ways is this most likely to happen?

• Ice forms at the surface first.

• The lake freezes from the bottom up.

• All the water in the lake turns to ice at the same time.

• The lake freezes from the centre first, and then into the banks.