Task: Students place in order four beakers of copper sulphate solution from most to least concentrated. They then explain what would happen if two beakers were put together, and explain the term "concentration". Assessment focus: solutions.

Curriculum Links:

Science capabilities

The capabilities focus is brought about by the conversations you have and the questions you ask.

Capability: Gather and interpret data

This resource provides opportunities to discuss and find out about the "concentration" of crystals in different solutions.

A [the amount of substance in a given volume of solution]

difficult

Trialled with 166 Y10 students

Diagnostic and formative information:

If students know the definition, but cannot answer question a), it is likely that the problem is mathematical, and is related to proportional reasoning skills.

For question a) the most common response in the trial was D,C,B,A (39% of students) and then A,B,C,D (23% of students). This suggests that most students attended to only the amount of water or the amount of crystals, but not both.

In question c) 10% of students chose option D,"paying attention to details", as the best definition of concentration, suggesting some confusion with the meaning of "concentration" in the context of science compared with the context of their every day lives. 35% of students gave the correct answer (A), 23% gave (B) and 27% gave (C.). The fairly even spread of responses would suggest large numbers of students were guessing.