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1. UNIT 7: MATTER, ENERGY AND ELECTRICITY
1. MATTER
Matter is made up of one or more substances which consist of tiny particles,
called atoms.
There are two types of matter:
 Pure subtances: These contain only one type of component which cannot be
separated into other substances. For example, oxygen.
 Mixtures: These contain two or more pure substances. For example, sea
water.
Furthermore, there are two different types of mixtures:
 Heterogeneous mixture: In these mixtures, the different components can be
distinguished.
 Homogeneous mixture: in these mixtures, the different components cannot be
distinguished.
ATOMS SUBSTANCE
S
MATTER
PURE SUBSTANCE
MIXTURE
HETEROGENEOUS
MIXTURE
HOMOGENEOUS
MIXTURE

2. 2. SEPARATION OF MIXTURES
FILTRATION EVAPORATION DISTILLATION DECANTATION
ENGLISH
Is used to
separate solids
from liquids
In used to
separate solids
from liquids
Is used to
separate liquids
that have
different boiling
points.
Is used to
separate liquids
that have
different density.
ENGLISH
In heterogeneous
mixtures
In Homogeneous
mixtures
In homogeneous
mixtures
In heterogeneous
mixtures.
MAGNETISM: when one of the elements of the mixture of two elements is a metal like
iron, you can use a magnet to attract this material.
SIEVE: when you need to separate two solids with different size you can use a sieve.
3. PHYSICAL CHANGES (page 76 NATURALS BOOK)
4. CHEMICAL REACTIONS:
Chemical changes happen when the original matter transforms into other new
substances.
There are many types of chemical reactions, for example:
Oxidation: happens when some metal substances, combine with oxygen in the
presence of water. As a result, rust is produced.

3. Combustion: happens when objects or substances are burned. This type of reaction
also needs oxygen and produces gases.
Fermentation: is a chemical reaction that happens in some living things, such as
yeast and bacteria.
5. CHEMICAL ELEMENTS:
O: oxígeno. Mg: Magnesio. S: Azufre.
N: Nitrógeno. Fe: Hierro. K: Potasio.
Ca: Calcio. Au: Oro H: Hidrógeno
C: Carbono Hg: Mercurio
P: Protones. N: Neutrones E: Electrones
Z=P=E
N=A-Z
6. ELECTRICITY:
Objects usually have the same number of positive and negative charges. This means
they are electrically neutral. However, negative charges can move from one object to
another when objects come into contact or are rubbed against each other.
- An object that loses negative charges becomes positively charged.
- An object that gains negative charges becomes negatively charged.
Electrically charged objects interact with each other in two different ways. Objects
with the same charge repel and objects with opposite charges attract.
Not all materials allow electrical charges to flow the same way:
- Insulators, such as glass, plastic and wood, do not allow electrical charges to move,
so electric current does not flow through them.

4. -Conductors, such as most metals, allow electrical charges to move freely, so electric
current flows easily through them.