Heat (Part 2)

Identify A, B & C to complete the concept map.

• A - Sun, B - Keep things warm, C - Drive the water cycle

• A - Sun, B - Keep things cold, C - Drive the water cycle

• A - Candle, B - Keep things warm, C - freeze the water

• A - Candle, B - Keep things cold, C - Drive the water cycle

Give one example of each type of heat source stated.

• Electrical appliance - toaster, Natural Source - hairdryer

• Electrical appliance - geyser, Natural Source - volcano

• Electrical appliance - oven, Natural Source - volcano

• Electrical appliance - sun, Natural Source - geyser

Peter rubs his hands together when his hands feel cold. Explain briefly how rubbing his hands together would make him feel better.

• By rubbing his hands together, air is produced to warm his hands.

• By rubbing his hands together, heat is produced to warm his hands.

• By rubbing his hands together, heat is produced to cool his hands.

• By rubbing his hands together, water is produced to warm his hands.

Diana placed a drop of blue ink into a narrow glass tube. The glass tube was inserted into a rubber bung which was fitted into an empty conical flask.

The conical flask was then placed in a basin of hot water.

What would Diana observe?

• The drop of blue ink drops into the conical flask.

• The drop of blue ink remains stagnant.

• The drop of blue ink drops a little & rises up the glass tube.

• The drop of blue ink rises up the glass tube.

Diana placed a drop of blue ink into a narrow glass tube. The glass tube was inserted into a rubber bung which was fitted into an empty conical flask.

The conical flask was then placed in a basin of hot water.

What would Diana observe if the flask was placed in a basin of ice water?

• The drop of blue ink would move down the glass tube.

• The drop of blue ink would rise up the glass tube.

• The drop of blue ink would move down and raise up the glass tube.

• The drop of blue ink would not move.

Diana placed a drop of blue ink into a narrow glass tube. The glass tube was inserted into a rubber bung which was fitted into an empty conical flask.

The conical flask was then placed in a basin of hot water.

What does this experiment show?

• It shows that air expands when heated and contracts when cooled.

• It shows that air contracts when heated and expands when cooled.

• It shows that water expands when heated and contracts when cooled.

• It shows that glass tube expands when heated and contracts when cooled.

Three rods, each made of a different material, had a pea stuck to one end by some baking chocolate. All three rods were placed in a beaker of boiling water. All the peas fell after some time. The times the peas took to drop off the rod were recorded.

Which rod is the poorest conductor of heat?

• Rod A

• Rod B

• Rod C

Three rods, each made of a different material, had a pea stuck to one end by some baking chocolate. All three rods were placed in a beaker of boiling water. All the peas fell after some time. The times the peas took to drop off the rod were recorded.

Arrange the rods from the best conductor of heat to the poorest conductor of heat.

• Rod A, Rod B, Rod C

• Rod B, Rod C, Rod A

• Rod C, Rod A, Rod B

• Rod C, Rod B, Rod A

Three rods, each made of a different material, had a pea stuck to one end by some baking chocolate. All three rods were placed in a beaker of boiling water. All the peas fell after some time. The times the peas took to drop off the rod were recorded.

What type of material makes the best conductor of heat? (Choose 2 answers)

• Aluminium

• Styrofoam

• Wool

• Mercury

Mrs Chung took a jar of baby food from the refrigerator. She wanted to feed her son but could not unscrew the metal lid.

She suggest one way to enable her to unscrew the lid. Give a brief explanation.

• She could invert the bottle of baby food and dip the lid into a basin of hot water for several minutes. This would help the lid to gain heat and expand.

• She could heat up the jar directly over a flame for several minutes. This would help the jar to gain heat and expand.

• She could invert the bottle of baby food and dip the lid into a basin of cold water for several minutes. This would help the lid to reduce heat and contract.

• She could force open the lid with a spoon.