Thank you for your help.

For part(a) ---The areas of exposed surfaces to the surrounding air as well as the area of contact between the ice and the materials affect the time taken for the ice to melt.What's your view?

For part(b) --- The temperature of the ice remains the same, while the temperature of material X decreases.Do you agree?

I do not quite agree with either of the answers provided, however, first I will make a general assumption that the temperature of the table, Material X and Material Y are all above 0 degrees at the start of the experiment. I make this assumption because if they were at 0 degrees then there would be no heat transfer making the experiment redundant.

With Part A, it is worth 1 mark and therefore we are looking for the most correct answer. The reason is because the amount of surface area between Material X and Block A is greater than the surface area between Material Y and Block B. [The amount of heat transfer is proportional to the surface area. - not in P6]

To address the surrounding air consideration. It is given that the temperature of the air is 0 degrees which is the freezing point of water. Although, the temperature of ice can be below 0 degrees, there is no indication that the ice's temperature is anything but 0 degrees. Therefore, heat transfer between the ice block and the air will only occur once the ice start's to melt due to heat transfer from the Material.

Part B - Assuming the initial temperature of Material X > 0 degrees.
The temperature of Ice block A increases.
The temperature of Material X decreases.

You may also wish to note that heat transfer (and conductors) is part of the P4 syllabus. I will check with a P6 science teacher if it is repeated in P6, however, the P6 science books I have do not discuss heat transfer.

Chris Rogers wrote:

To address the surrounding air consideration. It is given that the temperature of the air is 0 degrees which is the freezing point of water.


Hi Chris

Thank you for your quick response.

Heat is a topic in P4 Science. However this question about heat transfer is from SCGS P6 SA1 2008, hence this explains the heading.

1)Interesting, how did you infer that the surrounding air is at 0 degrees Celsius, given the information in the question?

2)During phase transitions, such as ice to water or water to steam, the temperature remains
constant, but a change of state occurs. Therefore, the temperature of ice remains the same. Heat is conducted from the material to melt the ice, hence there is a decrease in temperature.

A good link from a Google’s search
www.thenakedscientists.com/HTML/content/...fastest-melting-ice/

Thanks for the link - really interesting read.

As for the surrounding air temperature ..... I came to that conclusion because I read the question incorrectly. Must be getting old. I read the air was 0 degrees at not the ice block. Given this, I would alter the logic slightly and have a similar result ...

It is not a fair experiment because 1) the surface area of the ice blocks on the two Materials being "tested" is different; 2) the surface area, of the ice against the surrounding air is also different. I would still choose to answer with the first part as we are trying to determine which Material is a better conductor and therefore the first answer is more appropriate given the context.

With Part B, yes that is correct that temperature remains the same during the change of state of material like solid to liquid or liquid to gas. In this case, ice to water. This is due to the fact that the kinetic energy of both the ice block and (new) water remains the same when there is a change of state. Over time the temperature will adjust to the point where the air and the water (all the ice has melted) will equalize. Again, I would need to check to see how specific / simplified an answer P6 kids are expected to provide given this is only worth one mark. That said, if they are taught about temperature during a change of state then the answer would be as you have suggested.