Unit 2: matter and energy. 2º ESO.

1. UNIT 2: MATTER
AND ENERGY

2. ENERGY
 Energy is the capacity for doing work or to produce
heat.
 Energy cannot be created or destroyed, it can
only be transformed from one form into another.
 Types of material systems depending on the
transference:
 Open system: You are able to exchange matter and
energy.
 Closed system: You can exchange energy (as heat or
work), but not matter.
 Isolated system: You can’t exchange any of heat, work, or
matter with the surroundings.
 Heat and work can produce transformations in
matter.

3.  A body has:
 Potential Energy: stored energy.
Energy
 Kinetic Energy: the energy of motion. Ex: A roller
Energy
coaster.
 Substances like wood, coal, oil, and gasoline have
stored energy because of their chemistry they can
burn.

4. FORMS OF ENERGY
 Mechanical
 Electrical
 Thermal
 Electromagnetic
 Chemical
 Nuclear
 Internal
Energy can be
transferred, or
converted, from
one form to
another!

5. MECHANICAL ENERGY
 Energy associated with the motion of an object.
(Kinetic and potential energy)
 Chewing
 Frog Dancing

6. THERMAL ENERGY
Total energy of the particles in a
substance or material.
 All objects give off
thermal energy
 Ice cream melting
gains thermal
energy

7. CHEMICAL ENERGY
Potential energy stored in chemical
bonds.
 Food
 Fire Cracker
 Stomach
 Battery

8. INTERNAL ENERGY
It is the total energy contained by a
body, related to atoms, molecules etc.

9. ELECTRICAL ENERGY
Moving electrical charges that
produce electricity and energy.
 Lightening
 Batteries

10. ELECTROMAGNETIC ENERGY
 Energy that travels in waves
 Visible light
 UV Rays
 Microwaves
 Radio

11. NUCLEAR POWER
Energy stored in the nucleus of an
atom from fission or fusion
 Sun
 Stars
 Nuclear Power
Plant

12. SOURCES OF ENERGY
 Renewable energy: It comes from natural resources
such as sunlight, wind, rain, tides, and geothermal
heat.
 Non-renewable energy: resources which can’t be
used again and again because they run out. Ex: Fossil
fuels.

13. ACTIVITIES
1.What happens during any change?
2.Write an example of open, closed and isolated system.
3.What type of material system (open, closed isolated) is
a pressure cooker with food inside which is being
heated:
a) Before the security valve expels water vapour.
b)When the security valve expels water vapour.
4. What’s energy?
5.Two bodies, A and B, are isolated from the
environment. If body B gains 500 J of energy, what
has happened to body A?

14. 6.Name the type of mechanical energy a body has
when:
a) It’s at rest on the top of a roof.
b) It reaches the ground at a speed of 3 m/s.
7.What’s a nonrenewable source of energy? And
renewable? Give examples of both.
8.In what units are heat and work measured?
9.Fill in the blanks using these words: joules-
transformed-energy-material system-destroyed-
same.
_______is the capacity that a _______ has to produce
changes. Energy is measured in______ In any energy
transfer, the total amount of_______ before the transfer
remains the__________ as the total amount
of_______afterwards. Energy is not______or________,
it’s just___________.