• More students described a method than explained why it would work.
• It was more difficult for them to describe a method for slowing down melting than speeding up melting. This is possibly because they are more familiar with melting things, so the thinking steps required to reverse the process are more complex.
• None of the students in the trial included any ideas of fair testing. However, the wording of the questions did not signal that they should think about this.
• Some students focussed on the time aspect rather than the concept of heat when planning their method.
  • You would take like 10 hours.
  • Leave it in there for weeks and weeks.
• None of the students in the trial allowed for a comparison to be made that would show that their method was "quicker" or" slower". To do this they would either need to have an example to compare with, or include a way of timing.
• For question b), some students gave another method (and explanation when they gave one) that would speed up melting instead of slowing it down. Some students, although fewer, gave a method for question a) that would slow down melting instead of speeding it up. These students possibly:
  • struggled with the concepts of quickly and, in particular, slowly; or
  • misread the question.
• Most of the trial students were able to separate their methodology from their explanations, although a few conflated them.
• About a third of the trial students did not attempt to describe or explain a method for question a) and even more did not do so for question b). One possible reason is that some students may have struggled with or resisted the writing load of this task, especially as it was the last question in the trial set.

Examples of good Level 2 descriptions of methodology
The following examples clearly describe all the steps of a method. The information is presented in a logical order. The first two examples start with the verb that tells the reader what to do.

• Put the ice cube on the plate and put it outside in the sun to melt.
• Put the ice on the newspaper and wrap up and hold in hand while melting the ice.
• I would put it on the plate and put it in the sun or leave it on the bench.

Examples of good Level 2 explanations
The following examples clearly link the method described to a science idea.

• I think it would work because it (a fridge) is a thing that is just about as cold.
• Because the sun is hot
• Because the microwave will heat it and make it melt
• Because chilly bins keep things cold.

• I can squeeze the ice cube with the newspaper and it would melt the ice cube.
• I would push down on the newspaper with the ice in it.
• You would put the ice on the newspaper and put it on a high place and it would slide off and break on the ground.

Another student's method involved putting water in the chilly bin showing an awareness that ice will melt in water (because water is warmer than ice).
These students were unable, however, to explain why their method would work, possibly indicating that they did not understand the underlying science. This is in contrast to those who described a method that warmed the ice - they were more likely to be able to link to the underlying science concept, heat.
 

Very few of the students gave a scientifically valid explanation for slowing down the rate of melting.

For melting ice quickly, the trial students' choice of item was evenly spread between the plate and the newspaper, although about a fifth did choose the chilly bin. For melting ice slowly, the most common item chosen was the chilly bin, with few choosing the plate or newspaper.

Next steps

Assist students to understand that to slow down melting they have to remove the factor that causes melting. Ask them to predict, giving reasons, whether the ice cube will melt more slowly in the fridge, in a chilly bin, in the sun, or in the freezer. Carry out the investigation and then discuss the results.

For students who experience difficulty with "quickly" and "slowly" discuss or even role play some everyday examples, and measure or link to time taken. For example:

• A person who walks to school slowly will take longer to get there than someone who runs fast.
• Singing a song slowly will take longer than singing it quickly.
• Ice cream takes longer to melt on a cool day than a hot day because it melts more slowly.
• A marble will take less time to go down a steep slope than a gentle slope because it goes more quickly.

For those students who do not connect heat to melting, provide opportunities to experience melting in different contexts, e.g., ice, butter, ice-cream, chocolate, cooking. Go to Further resources for ideas for activities.

For those students who are secure with the idea that ice melts when it gets warmer, do some simple investigations exploring related concepts such as surface area and pressure. As these are more complex situations, discussions about students' ideas will probably be more productive than just writing them down.

For students who say a chilly bin is cold, ask how they can test this. If they decide to measure the temperature, they may need support to do this. They could try other ideas (try to use their suggestions) such as leaving the lid off and on and comparing the results, keeping things hot as well as cold inside a chilly bin, and putting extra ice or slicka pads in and comparing results to a chilly bin without these. Encourage them to keep refining their explanations in view of the evidence from the investigations.