Strength and loads, flexibility and shape. Good and bad thermal insulators around the home. Testing for better thermal insulators. Testing for conductivity. Changes in state - maintenance of shape and volume.
Similar size means similar volume.
Level 5 Safety check of school based on characteristics of materials. Playground hardness - natural v. manmade. Thermal insulation in a compost bin. Devising fair tests to compare different compost bins. Testing for conductivity and uses.