Darren set up an experiment as shown.

picture

All the rods were of the same size but made of different materials. He placed the same amount of wax on the tip of each rod and poured boiling water into the container as shown.

He recorded the time taken for the wax to fall off each rod. The results are shown in the graph below.

picture

Which material, W, X, Y or Z, should be used to make the handle of a frying pan?


X
X
W
W
Z
Z
Y
Y

Explanation/Tips

The wax on rod Y took the longest time to melt, showing that heat from the boiling water took the longest time to travel through rod Y to the wax, therefore rod Y is made of the material that is the poorest conductor of heat.

The handle of a frying pan needs to be made of a poor conductor of heat to allow heat to flow from the flame to the users hand slowest to protect her hand from being burnt. Hence, material Y is the most suitable.

Flip