MATTER AND FORCES

STATES OF MATTER
1. Solids
  1. Definite shape and volume (holds shape and volume).
2. Liquids
  1. Definite volume and indefinite shape. They take the shape of the container.
3. Gases
  1. Indefinite volume: they can be compressed. Indefinite shape. They take the shape of the container
CHANGES OF MATTER
1. Physical
  1. Reversible and irreversible
2. Chemical
  1. Most chemical changes are irreversible. Combustion,oxidation and fermetation.
3. Matter suffers changes of state
MATTER AND ITS PROPERTIES
1. Matter is made out of atoms.
2. colour, odour and taste.
3. VOLUME: how much space matter occupies. We measure volume in mililitres (ml). 1l= 1000 ml
4. DENSITY: The amount of matter in a volume. We measure it in kilograms per litre (kg/l)
5. HARDNESS is the scratch-resistance of a solid. Diamonds are the hardness natural solid. Talc is the softess material.
6. THERMAL CONDUCTIVITY is the ability of the susbtances to conduct or transfer heat.
7. SOLUBILITY: is the ability of a substance to disolve in another substance and form a solution. Sugar disolves well in water whereas oil does not.
8. MASS is the amount of matter in an object. An apple has a greater mass than a grape. We measure mass in grams (g). 1kg=1000g.
WHAT TYPES OF MATTER ARE THERE?
1. PURE SUBSTANCES
  1. Consists of only one type of matter such as table salt, silver, gold, copper or pure water.
2. MIXTURES
  1. are made up of two or more pure substances.
  2. HOMOGENEOUS MIXTURES: such as the air we breathe or sea water. We cannot see the individual substance.
  3. HETEROGENEOUS MIXTURES: such as sand or a salad. We can see the individual substances.
  4. We can separate the substances in mixtures through FILTRATION, EVAPORATION AND SIEVING
FORCES AND ITS EFFECTS
1. Forces can make things MOVE, STOP, SPEED UP, SLOW DOWN or CHANGE DIRECTION.
2. NON-CONTACT FORCES
  1. MAGNETISM: force of attraction or repulsion caused by magnetic material, such as magnets.
  2. GRAVITY is a force which attracts all objects towards each other, such as planets which have a stronger gravitational force. In space there is no gravity and astronauts float there.
3. Force is a push and pull that acts on an object. We can see their effects.
4. CONTACT FORCES
  1. FRICTION is a force that exists when two objects rub against each other. It acts in the opposite direction of movement. It can slow down or stop a moving object.
  2. BUOYANCY is teh ability of objects to float. It is an upward force which acts in the opposite direction to gravity on objects immersed in a liquid.
5. WHY SOME OBJECTS FLOAT IN WATER AND OTHERS SINK?
  1. DENSITY (kg/l) explains why some objects float in water while others sink.
  2. If an object has lower density than water, it floats. If an object has higher density than water , it sinks.
  3. The density of water is 1 Kg/l. The density of steel is around 8 kg/l.
  4. The ability to float depends on the AVERAGE DENSITY that take into account all materials that the object is made of.
A NEW WORLD OF MATERIALS
1. Nearly everything we use is made of materials created or modified by scientists and engineers (man-made materials).
2. ALLOYS: It is created by mixing two or more elements, one of wich must be a metal (cooper, silver,...). BRASS is an alloy of copper and zinc.
3. STEEL is the most commonly used alloys in everyday life. STAINLEES STEEL is alloy which resists rust and corrosion.
4. ARTIFICIAL JOINTS is made of a special CERAMIC MATERIAL which is hard and has no effects on our body.
5. CERAMIC material are also used by dentists to repair teeth.
6. New materials in every day life are NON-STICK CERAMIC COATING for cookware; POLAR FLEECE FABRIC to made pieces of clothing from recycled plastic bottles and CONCRETE CLOTH.
7. NYLON ia a chaper man-made material sobstitute for silk (fabric, cookware, electronics industry). PLASTIC is used in almost all areas of everyday living due to their versatility (construction, packaging, toys..). POLYESTIRENE is a versatile plastic used to make a wide variety of consumer products (Refrigerators, food trays, food packaging,...)

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MATTER AND FORCES

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