Thermal energy and light are different forms of energy that can be transferred and transformed. Thermal energy is the total kinetic energy of particles in an object and causes temperature, while light is a type of electromagnetic radiation. Thermal energy can be transferred through conduction, convection, or radiation between objects and drive processes like chemical reactions, phase changes, and expansion. Light can travel through transparent, translucent, or be blocked by opaque materials and is reflected by mirrors and refracted when changing mediums. When light is absorbed by an object, it is transformed into thermal energy.

1. natural
Heat and Light

2. What’s the difference between temperature and
heat?
Temperature and heat refer to two different things. The temperature of an object
tells us how hot the object is. Heat is the amount of thermal energy that an
object has.

3. How does thermal energy travel through objects?
conduction
radiationconvection

4. What are conductors and insulators?
Some materials are good conductors. This means that they transfer thermal
energy easily.
Other materials don’t transfer thermal energy easily. We call these materials
thermal insulators.
conductor
insulator

5. What are the effects of thermal energy?
Expansion: Thermal energy causes the molecules in a solid, liquid
or gas to vibrate.
Evaporation: When thermal energy is applied to a liquid, it
changes into a gas. This process is called evaporation.
Chemical changes: Thermal energy can cause chemical changes.
Melting: When a solid receives thermal energy, it changes into a
liquid. This process is called melting.

6. How do different objects react to light?
This glass is transparent:
it doesn’t block light.
This object is opaque: it
blocks the light
completely.
The curtains are made of a
translucent material: they
block some light, but
some light passes through
the material.

7. What’s light?
Light is radiation that we can see with our eyes. It’s made up of microscopic
particles that travel in waves. Light travels in straight lines.
We use light from the Sun to see and to produce electrical energy with solar
panels. We use light energy to see at night. Light energy enables us to see things
on television and computer screens.

8. How do mirrors reflect light?
Light travels in a straight line from the object to the mirror. The mirror reflects
the light causing it to change direction.

9. What’s refraction?
When light passes through some transparent substances, like water, the light
energy changes direction slightly. This process is called refraction.

10. How is light transformed into heat?
When light energy hits an object, some of the energy is absorbed by the object. This
energy makes the molecules of the object vibrate faster. If we touch the object, we
feel this vibration as heat.

11. What have we learnt?
convection radiation
Thermal energy travels from one object to another through...
conduction

12. What have we learnt?
chemical changes
Thermal energy causes...
melting evaporation expansion

13. What have we learnt?
transparent translucent
Objects can be...
opaque