Assessment content centers on common, real-world science contexts that are relevant to students, both during and outside of classroom instruction. Using a context of ice melting or mixing powders in drinks are a few options to assess a concept like conservation of weight.
Putting substances found in a lab, such as hydrogen dissolving in palladium, as your assessment context when it may not be commonly used during instruction. These unfamiliar substances are less relevant for students.
Ensure that chosen contexts or phenomena are equally likely to be familiar to students with and without sensory impairments or communication support needs.