The cap of a glass jar was too tight to twist open.

Emily poured hot water over the metal cap to solve the problem.

What was Emily trying to achieve?

• Let the metal cap gain heat and expand.

• Let the metal cap loss heat and contract.

• Let the glass jar gain heat and expand.

• Let the glass jar loss heat and contract.

The metal cap of a glass jar was too tight to twist open.

Esther inverted the jar into a trough of hot water.

The metal cap could be removed from the glass jar easily after that. Why?

• Metal cap gained heat and expanded.

• Glass jar gained heat and expanded.

• Metal cap expanded more than the glass jar.

• Glass jar expanded more than the metal cap.

The metal ball was slightly too big to pass through the ring.

What could be done to let the ball pass through the ring?

(A) Heat the metal ball.

(B) Heat the metal ring.

(C) Cool the metal ball.

• (B) and (C) only

• (A) only

• (A) and (B) only

• (C) only

The metal ring was slightly too big to stop the metal ball from passing through.

What could be done to stop the ball from passing through the ring?

(A) Heat the metal ball.

(B) Heat the metal ring.

(C) Cool the metal ball.

• (B) and (C) only

• (A) only

• (A) and (B) only

• (C) only

A beaker of hot water is placed on a wooden table.

Which of the following actions will cool the water fastest?

• 
• 
• 
• 

A beaker of hot water is placed on a wooden table.

Which of the following actions will cool the water fastest?

• 
• 
• 
• 

An aluminium plate and a plastic plate were left on the table for a long time.

Kai Ling placed her hands on the plates as shown.

She felt that the aluminium plate was colder because _______.

• the aluminium plate had a lower temperature than the plastic plate

• the plastic plate had a lower temperature than the aluminium plate

• the aluminium plate gained heat faster from the hand than the plastic plate

• the plastic plate gained heat faster from the hand than the aluminium plate

Ms Chong inserts her left hand into 50^oC water and her right hand into 20^oC water for a long time.

She then inserts both hands into 30^oC of water immediately.

How will her hands feel?

• Both hands feel cold.

• Both hands feel warm.

• Left hand feels cold but right hand feels warm.

• Left hand feels warm but right hand feels cold.

Two beaker of hot water at 80^oC are placed on a table. Which graph below best shows the cooling curve of the two beakers of water?

• 
• 
• 
• 

Two beaker of hot water, 60^oC and 80^oC, are placed on a table. Which graph below best shows the cooling curve of the two beakers of water?

• 
• 
• 
•