Read About Thermal Energy

Which statement best defines thermal energy?

• Energy of vibrating particles in a substance

• Energy stored only in chemical bonds

• Energy from objects because of their height

• Energy created by electric charges moving

What does temperature measure in a substance?

• Average kinetic energy of its particles

• Total number of atoms in the sample

• Exact speed of each individual particle

• Amount of space between the molecules

Compared to a colder object, the particles in a hotter object are moving

• faster on average than in the colder object

• slower on average than in the colder object

• at the exact same speed as the colder object

• only when heat is added from electricity

Which change happens when ice melts into liquid water?

• Particles move faster and slide past each other

• Particles stop moving and lock permanently

• Particles move slower and pack closer together

• Particles spread infinitely with no collisions

Thermal energy naturally moves

• from a hotter area to a colder area

• from a colder area to a hotter area

• only when both areas have equal heat

• only through metals and never through air

What is the term for thermal energy moving from one place to another?

• Heat

• Work

• Friction

• Power

Which material would best reduce thermal energy transfer around a hot drink?

• Foam cup with trapped air spaces

• Thin metal cup with shiny surface

• Glass cup with thick liquid inside

• Wet cloth wrapped around the cup

Why do insulators like foam and cardboard work well?

• They contain air spaces that transfer energy poorly

• They are heavy and press particles together tightly

• They allow particles to collide more frequently

• They reflect light which cools the container quickly

A thermos uses a vacuum layer mainly to

• reduce particle collisions that carry thermal energy

• increase air pressure to warm the liquid faster

• add more molecules to absorb cold from outside

• speed up conduction through the container walls

Which reaction releases thermal energy to its surroundings?

• Burning wood in a campfire

• Activating an instant cold pack

• Evaporating water into steam

• Dissolving salt into cold water