Formative Assessment

Can students use their observations of properties of minerals as evidence that a mineral is present in a rock?

In their wrap up of an investigation of minerals, students search for familiar minerals in a small collection of rocks.

As they make claims, you’ll find evidence of their ability to use the properties of minerals the class observed (such as color, luster, translucence, hardness, friability) as evidence to support a claim.

As you interpret a student’s statement, assess the strength of the evidence the student chooses.

• Strong: I think quartz is in granite because I see grains that are shiny, translucent, hard.
• Weak: I think graphite is in granite because I see a grain that is black. The student does not take other properties of graphite into consideration such as leaving black marks on the fingers when rubbed.

After a student makes a claim, a next step might be to ask the class to take a stand on the strength of the evidence that supports the claim.