Post on 17-Dec-2015
Metals conduct electricity and heat and non-metals do not.
Elements
An element is a substance made from the same type of atom.
A periodic table shows all the elements known to exist.
Elements can be either metals or non-metals.
Elements are arranged in rows called periods and columns called groups.
The periodic table has 8 groups:•Group 1 = Alkali Metals•Between Groups 2 & 3 = Transition Metals•Group 7 = Halogens•Group 0 = Noble gases
Alkali metals are very reactive and have to be stored in oil e.g. Potassium, Sodium and Lithium.
The Halogens are also very reactive e.g. Chlorine and Fluorine.
Noble gases are unreactive.
Carbon is the only non-metal to conduct electricity.
The basic pieces of science equipment we use are:•Bunsen burner•Tripod•Gauze mat•Heat mat•Beaker•Test tube
•Boiling tube•Test tube holders•Conical flask•Test tube rack•Evaporating dish•Filter funnel
Metals can be both malleable and ductile.
Malleable means the metal can be shaped easily e.g. into a candlestick holder.
Ductile means the metal can be beaten flat e.g. gold foil and tin foil.
Electricity
An electrolyte is the name given to a liquid that conducts electricity in a circuit
Switch Cell Battery
Lamp Voltmeter Ammeter
Resistor Variable resistor
Motor
Circuit symbols
Buzzer Bell Wire
In a series circuit there is only one possible route for the electricity to travel around
In a parallel circuit there is more than one route for the electricity to travel around – there are branching loops
Household appliances that are connected to parallel circuits can be switched on and off separately
An ammeter is used to measure the current in a circuit. Current is measured in Amps.
An ammeter is connected to a circuit in series
In a series circuit the current is the same at every point
In a parallel circuit the current from the branches add up to the current from the battery
A voltmeter is used to measure voltage. Voltage is measured in volts.
A voltmeter is connected to a circuit in parallel
The voltage is divided between all the components in a series circuit so there is none to return to the battery.
The voltage in each branch of a branches in a parallel circuit is equal to the voltage coming from the battery.
Heat
Heat is the total amount of heat energy in an object
Temperature is the average speed of vibration of the particles
Heat flows through a solid by conduction
Vibrating particles make other particles vibrate around them as this spreads through an object we say that heat is being conducted
The faster a particle vibrates the hotter it gets
A substance that lets heat flow through it easily is called a conductor
A substance that does not let heat flow through it is called an insulator
Air is a good insulator
Some examples of good conductors of heat are:•Metals•Copper pipes•Single glazed windows
Some examples of good insulators in the home are:•Double or triple glazed windows•Wall insulation•Silver backed board
Heat flows through liquids and gases by convection currents
As the particles heat they rise and as they move up and away from the heat they cool and sink again, this creates a current
Convection currents can be used everyday by:•Birds to gain altitude•Inside the Earth magma flows•The Gulf Stream ocean currents
Heat may be transferred through a vacuum by radiation
Radiant heat travels by Infra-red waves
A dull surface will absorb more radiant heat and a shiny surface will reflect more
A black surface will absorb more radiant heat and a white or silver surface will reflect more