grade 6 , con 4, lesson 6

Metallic parts of a bridge........... in different temperatures.

• contract only

• never expand or contract

• expand only

• expand and contract

When the kinetic energy of liquids decreases, they may

• expand.

• contract.

• evaporate.

Railroad tracks are made up of

• glass.

• coal.

• plastic.

• iron.

Engineers leave........... Between railroad tracks

• small spaces

• very large spaces

• large spaces

• no spaces

Materials by their temperatures.

• expand – decreasing

• contract - decreasing

• contract – increasing

• melt – decreasing

Put (✓) or (X) : Engineers use expansion joints to keep bridges safe.

• True

• False

Put (✓) or (X) : Temperature increases in hot weather causing contraction of materials.

• True

• False

Put (✓) or (X) : Railroad tracks are made up of iron.

• True

• False

Put (✓) or (X) : No spaces are left between railroad tracks.

• True

• False

Put (✓) or (X) : Without leaving spaces between railroad tracks, train accidents may occur.

• True

• False