Day 3 STAAR Glow Olympics-5.5A Checkpoint Quiz

A science class tested three properties of different materials. The results are shown below.

Based on the table, which material would be best to insulate electrical wires?

• wood

• plastic

• copper

• steel

A student is asked to design a sleeve for a cup that will insulate thermal energy and not feel hot to the touch when the cup is filled with hot liquid.

The student has four materials to choose from. Which of these materials is least useful as an insulator?

• cardboard

• plastic

• rubber

• aluminum

Which of these is the best conductor of electricity?

• glass rod

• copper penny

• plastic tubing

• cotton string

The table lists some physical properties of two objects.

Based on their properties, which of the objects is most likely a metal?

• Object 1, because it is a solid that is less dense than water

• Object 2, because all metals float in water

• Object 2, because metals conduct thermal energy and electricity

• Object 1, because it can be used to provide insulation for thermal energy

Two wires carrying electricity can create a spark if they come too close together. This spark can start a fire. Wires carrying electricity are usually covered with plastic to keep them from starting a fire. Why does the plastic keep the electricity from starting a fire?

• Plastic is a good insulator

• Plastic can melt when heated

• Plastic is softer than wire

• Plastic conducts electricity