Formative Assessment

Do students know the weights of the 8 cubes in grams? Do they understand why they'll use grams as the standard unit of weight?

Look at notebook entries to find evidence that the student has an accurate record of the weight of each cube in grams. You'll also find evidence of their understanding of the rationale for using grams to weigh things.

Use these criteria to interpret student work:

• The cubes should weigh approximately:
  Pine 7g, Oak 13g, Nylon 18g, Acrylic 19g, PVC 22, Aluminum 44g, Steel 128g and Copper 147g. Humidity will affect the weights of pine and oak, and the (in)accuracy of the balances may cause the measurements of all cubes to vary by one or two grams.
• Rationales for using grams:
  this is the unit used by scientists around the world, like paper clips, they are light enough to discriminate between objects that are very close in weight.

Next steps might include selecting another small object, estimating its weight in grams, and weighing it.