science : - Coggle Diagram
Metals and Non- Metals
Ninety- two elements are naturally found on earth. They can be classified as Metals, Non- Metals and semi- metals or metalloids.
METALS= Metals are naturally occurring elements. There different properties make individual elements ideal for a large variety of uses in everyday life.
PROPERTIES OD METALS= Metals have a number of physical properties in common but are still slightly different.
MELTING POINT= This is the temperature at which a solid material turns to a liquid. The melting point of ice is 0 degrees. Most materials that are pure chemicals have a unique melting point.
Alkali Metals are soft with low densities, e.g sodium and potassium.
HIGH DENSITY= high density is when objects feel very heavy for their size.
METALLIC BONDING= metals are held tightly together by electrons. The electrons come from the outer shells of the atoms and hold the atoms together.
ALLOYS= sometimes metals are more useful when they are pure. Many metals are better and more useful for certain jobs when they are combined with other metals and non- metals.
STEEL=[ most pure iron is changed into alloys of steel were carbon and metals are added to the iron.
PHYSICAL PROPERTIES= physical properties are the characteristics and features that define any material. Every material has a different set of properties that makes it perfect for some jobs and useless for other.
NON- METALS= there are 21 non- metal elements. Many are liquids or gases. They are Carbon, sulphur, oxygen and Nitrogen.
PROPERTIES= Non- metals properties are the opposite of Metals properties.
CONDUCTERS OF ELECTRICITY= Non- metals are electrical insulators, which means that electrical currants cannot flow through them.
CONDUCTORS OF HEAT= Heat does not travel very well through Non- metals, so this makes them very good heat insulators.
METALS= Li, Na, Cu, Al, Mg, K, Fe, Zn, Si, Ge
NON-METALS= O, H, C, Ci, N, Si, Ge.
Speed, distance and time
SPEED= the distance travelled by an object in one unit of time.
CALCULATING SPEED= distance/ speed x time.
VELOCITY=the speed of a body and the direction in which its moving.
ACCELERATION= acceleration is the rate of change in velocity. The unit for acceleration is m/s squared.
Motion or movement happens around us everyday when your cycling, walking or getting the bus or car to school.
The speed of a car is measured in km/h or kph.
ACCELERATION= final velocity- initial velocity/ time taken.
When calculating speed make sure you have the distance value in metres and the time value in seconds.
Velocity and speed use the same units when measuring.
Velocity= the direction is usually given using the points of a compass e.g. north, south, east and west.
Skydivers reach a terminal velocity after falling for a short time.
In everyday conversation we use the word acceleration to refer to objects that are going faster and faster. The units for acceleration are ms2 or ms-2.
Acceleration is the change in speed divided by the time taken for the change.
force, work and power
FORCE= A force can cause a stationary object to move. A force can cause a object to move more quickly or more slowly. Or a force could move an object in a different direction.
The unit of force is Newton and the symbol is N.
DIFFERNT TYPES OF FORCE= different types of force are The force of gravity, Magnetic force, Electric force and force of friction.
WEIGHT= The weight of an object is the pull of the earth on it. Weight is a force.
Weight is measured in newton. Weight has a direction e.g. a force that acts towards the earth.
The weight of an object can change. Weight gets smaller as you ride upwards from ground level.
MASS= The mass of an object is the amount of matter in it. Mass is measured in grams or kilograms. Mass does not have a direction. The mass of an object remains constant.
MOMENTS OF A FORCE= Forces can cause objects to move. The movement can be in a straight line, kicking a ball straight ahead. Sometimes the movement is a circle. The blades on a windmill spinning. The moment of a force tells us how much spin or circular motion a force can cause.
LEVERS= Levers can be used to make a force more effective.
The moment of a force is equalled to the force multiplied by the distance between the force and the fulcrum. The fulcrum is the part about which the lever turns. A lever is any rigid body that which is free to turn about a fixed point called a fulcrum. When a lever is balanced by a number of forces, the sum of the clockwise moments acting on it is equal to the sum of the anti- clockwise moments acting on it.
Examples of levers are a scissors, a door and a wheelbarrow.
WORK= The unit of work is joule (j) work= force x distance
POWER= work done/ time taken. The unit for power is watt (w)
WORK is force multiplied by distance. PRESSURE is the amount of force acting on a unit of area. POWER is the amount of work done in a unit of time.