Science Flashcards
Principle of conservation of energy
Energy which can not be created or destroyed but transferred from one form to another
Energy transfers during motion the swing
GPE decreases and transferred into kinetic energy when increases
Energy transfers during motion the pendulum
GPE transfers into half KE when half way through the bottom of the swing transfers to full KE
Kinetic Energy formula
Kinetic energy = 1/2 x mass x Velocity2
GPE formula
GPE = mass x gravity x height
Efficiency formula
Efficiency = useful energy output/
total energy input
What are fossil fuels
Dead plants and animal remains
Renewable energy
Is an energy resource that never runs out
Renewable Energy sources
Solar
Hydroelectric
Wind
Non renewable energy sources
Fossil fuels
Nuclear
Conditions needed to make fossil fuels
Time, pressure and temperature/heat
Fossil fuel examples
Coal, gas and oil
How does a turbine and a generator produce electricity?
Wind moves the rotor blades which powers the generator
Why an element is radioactive
Has an unstable nucleus with an unstable amount of protons and neutrons
Alpha particles
Slow moving protons and neutrons
Alpha particles are stopped by
Few centimetres of air and thin sheet of paper
Beta particles
Fast moving electrons
Gamma radiation
High energy electromagnetic wave
Beta particles are stopped by
Several meters of air
Thin sheet of aluminium
Gamma particles stoped by
Thick sheet of lead
Why alpha is used in a pacemaker rather than beta or gamma source
Alpha can’t escape the pacemaker as it’s made of metal while beta and gamma would escape and damage tissue
Background radiation
Radiation that is always present and all around us
Sources of background radiation
Carbon 14 inside living organisms
Radioactive gas/radon emitted from granite rock
Potassium which contained in some food
Waste products from nuclear power stations
Medicine in hospital Cosmic rays
The solar system is made up off
Eight planets, moons, asteroids and comets that orbit the sun
Inner planets
Has a circular orbit and has a hard surface called rocky planets
Outer planets
Has an elliptical orbit and are dense balls of gas called gas giants
A light year
The distance travelled by light in one year
Formation of a star/sun
A nebula is made up of hydrogen gas and dust.
It became denser as gravity pulled particles together to form a protostar.
Nuclear fusion begins creating a main sequence star
What is a galaxy?
A huge collection of stars
What’s the name of our galaxy?
The Milky Way
The Big Bang theory
Galaxies are moving away from each other
The further away the galaxies are the faster they’re moving apart
The universe is expanded and cooled
Evidence of the Big Bang
All galaxies are moving away from us (seen through red shift)
The further away a galaxy is, the faster it’s moving away
Scientists detected CMBR thought to be left over from the explosion
What age is the universe (the Big Bang)
14 billion years
Steady state theory
Universe has always existed and the universe is constantly expanding and creating matter
The Big Bang theory is supported by?
CMBR
CMBR
Cosmic Microwave Background Radiation
Electricity
The flow of electrons in a circuit
Electricity
The flow of electrons in a circuit
Series circuit
Has only one path for electricity to flow
Parallel circuit
Has two or more paths for electricity to flow
Current
Amount of electricity flowing around a circuit
Current is measured by
Ammeter
Amps
A
Conductors
Materials that let electricity pass through
(Less resistance)
Insulators
Materials that don’t let electricity pass through (high resistance)
Voltage is measured by?
Voltmeter
Volts
V
Voltage
Amount of electrical energy supplied to a circuit or component
Current/amps in a series circuit
Stays the same throughout the circuit
Voltage in a series circuit
Decreases as the number of bulbs increases (Splits up)
Brightness of bulbs get dimmer
Current/amps in parallel circuit
Decreases as the number of bulbs increases (Splits up)
Voltage in a parallel circuit
Stays the same throughout the circuit
Conventional current flow
Positive terminal to negative terminal
Electron flow
Negative terminal to positive terminal
Electrical conductors
Copper, iron
Electrical insulators
Glass, wood, plastic and paper
How heat is transferred by conduction in poor conductors
Atoms are heated and gain energy
Vibrate more and greater amplitude
Heat is transferred from one atom to the next as kinetic energy
(Glass)
How heat is transferred by conduction in good conductors
Copper because it has free electrons which can move and collide into other atoms transferring heat energy quicker
(Metals)
Cell polarity
Cells and batteries have a long thin line represents a positive and short thick represents negative which provide voltage round the circuit
What are comets?
Large chunks of frozen rock covered by huge quantities of frozen water and gases
What are asteroids
Large chunks of rock that orbit the sun
