Physical Processes

Description:	Physical Processes (Key Stage 3)
Category:	Physics
Created by:	J Thomson on 2005-04-30

Question	Answer
In a series circuit, components are connected . . .	one after the other in a line ( like elephants in a circus ring)
In a parallel circuit, components are connected . . .	side by side ( like rungs on a ladder )
Current is measured using an . . .	ammeter connected in series
Voltage is measured using a . . .	voltmeter connected in parallel
The current in a series circuit depends on . . .	the number of cells and the number and type of components connected
The current in a series circuit is . . .	the same for all series components ( it is not 'used up' but returns to the battery)
When a battery is connected to a series circuit it transfers . . .	energy to the components ( e.g. a light bulb )
A magnetic field is a region of space where 'magnetic' materials experience . . .	a force
Magnetic materials include . . .	iron, steel, cobalt and nickel
Like magnetic poles will . . .	REPEL
Unlike magnetic poles will . . .	attract
A current in a coil of wire produces . . .	a magnetic field ( like that of a bar magnet)
An electromagnet works because . . .	an electric current flows in a coil of wire
Electromagnets are used in . . .	scrapyards for lifting iron and steel (e.g. old cars)
A relay is a device which uses . . .	an electromagnet as a switch.
The speed of a moving object is equal to . . .	distance travelled / time taken
Weight is . . .	the force of gravity acting on a mass
An unbalanced force will . . .	change the speed and direction of movement of an object
Balanced forces produce . . .	no change in movement of an object
A frictional force will . . .	slow down a moving object
Examples of frictional forces are . . .	air resistance or drag
If a car is streamlined this means that . . .	there is less drag due to air resistance
When a car skids this happens because . . .	there is not enough friction between the tyres and the road surface
Skiers can go quite fast downhill because . . .	there is very little fricition between the skis and the snow
An ice skater goes quickly because . . .	the force of friction is very low
A force can cause an object to turn if . . .	it acts about a pivot (e.g. a spanner)
The product of a force and its distance from a pivot is called a . . .	moment ( or torque)
If the moments on each side of the pivot are equal then . . .	the object is in equilibrium ( it will not turn)
A see saw works because . . .	the moments on each side of the pivot are equal ( or nearly so ! )
Pressure is equal to . . .	force / area
A ski does not sink into soft snow because . . .	the weight of the skier is spread over a large area
An ice skater exerts a large pressure on the ice because . . .	the blade of the skate is narrow
A thin wire is used to cut cheese because . . .	it exerts a large pressure on the cheese
Hydraulic brakes make use of . . .	pressure in a liquid
A drawing pin is easy to push in because . . .	it has a large head and a sharp point ( pressure is highest under the point)
In a uniform medium, light travels . . .	in a straight line at a finite speed ( 300 000 km/sec)
Objects which emit light are called . . .	luminous (e.g. Sun, fireflies)
Non luminous objects can only be seen because . . .	light scattered from them enters the eye
When light is reflected from a plane surface, the angle at at which it strikes the surface is equal to . . .	the angle of reflection from the surface
When light crosses a boundary between two different materials it is . . .	refracted ( changes direction and speed )
Isaac Newton explained that white light can be . . .	dispersed to give a range of colours
When a white object is viewed through a green filter it appears . . .	green because white reflects green light
When a red object is viewed through a blue filter it appears . . .	black because red absorbs blue light
An object which appears blue in white light does so because . . .	it reflects blue light ( and absorbs all other colours)
Sound waves can be heard because they . . .	make the eardrum vibrate
Older people are hard of hearing because . . .	they cannot detect higher frequencies of sound
Dog whistles cannot normally be heard by humans because . . .	dogs can hear higher frequencies than humans
If you listen to loud music for too long it can cause . . .	temporary deafness (hearing loss)
People who work in noisy factories need to wear ear defenders because . . .	loud noises cause deafness
Light can travel through a vacuum but . . .	sound cannot (it needs a physical medium such as air)
The speed of sound compared to the speed of light is much . . .	LESS
Lightning is always seen before we hear thunder because. . .	light travels much faster than sound
The loudness of sound depends on its . . .	amplitude
The frequency of a sound is usually called its . . .	PITCH
The Sun appears to rise in the east and set in the west because . . .	the Earth spins from west to east
The Earth completes one orbit around the Sun in the course of . . .	one year ( 365.25 days approximately)
The Earth and the other planets all revolve around . . .	the Sun
Some of the planets are closer to the Sun than the Earth. Which ?	Mercury and Venus
The largest of the planets is . . .	Jupiter
The furthest planet from the Sun is . . .	Pluto
The planets remain in orbit because of . . .	the Sun's gravitational pull
The Moon revolves around the Earth because of . . .	the Earth's gravity
Stars emit light but planets . . .	reflect light from the Sun
Planets far from the Sun move more slowly in their orbits because . . .	gravity decreases with distance
Artificial satellites are placed in orbit around the Earth to . . .	observe the Earth and its weather.
Spacecraft can also be sent away from Earth to . . .	explore the solar system
Renewable energy resources on the Earth include . . .	solar, wind, wave and tidal energy
Non -renewable resources of energy include . . .	coal, oil and natural gas
What is the name of an energy resource derived from things which were once alive?	Biomass
Electrical energy can be stored in a . . .	battery
The source of all our fossil fuels is . . .	the Sun
Fossil fuels formed . . .	millions of years ago from plants and animals
Electricity can be generated by . . .	coal, oil, gas, wind, waves, solar, biomass, etc . . .
The purpose of a power station is to . . .	produce electricity from a variety of fuels
Heat is a form of . . .	ENERGY
The amount of heat energy a body contains is indicated by its . . .	temperature
When heat energy is transferred from one body to another, it flows from . . .	hot to cold
Heat energy can be transferred in solids by . . .	conduction
Heat energy can be transferred in liquids and gases by . . .	convection
Heat energy can be transferred through a vacuum (space) by . . .	radiation
When a liquid is left in an open dish for several days it will . . .	evaporate
During conduction of heat, particles transfer energy by . . .	vibration
During convection, energy is transferred by . . .	the motion of particles
During the transfer of energy by radiation . . .	waves travel directly through space
Energy cannot be created or destroyed but it can be . . .	transferred from one form to another
Energy is always conserved but it may be . . .	dissipated (lost to the surroundings)
Energy usually escapes as heat. This means that . . .	less energy is available as a resource
Energy is used in a number of different ways in the home. Name three.	Electric light, heating, cooking, etc.
Health and safety are important issues for the use of energy in the home. Give one example.	Don't leave a chip pan on the cooker when it is turned on.
Scientists measure temperature in degrees . . .	celcius