Week 7 - Physical Science 2 Flashcards
Non contact forces
Gravity or magnetism
Electromagnetic spectrum
Range of light that exists
Blue - busy (faster)
Red - lazy (slower and bigger)
Light and colour frequency
Light and colour frequencies are different and individual
Each colour has its own wave length
Transmission of light
Light can travel through a vacuum
Transmitted light - let through
Reflected - turned after striking a surface
Absorbed - transformed into heat energy
Absorption
If a light wave of a given frequency strikes a material with electrons having the same vibrational frequencies, those electrons will absorb the light wave and turn it into vibrational motion and thermal energy
Reflection and transmission
Occur because the frequencies of light waves do not match the natural frequencies of vibration of the objects
Transparent
Can see through it
Vibrations of electrons are passed onto neighboring atoms through the material and reemitted through the other side of the object - such frequencies are transmitted
Opaque
Can’t see through it
The vibrations of the electrons are not passed from atom to atom of the material
The electrons of atoms on the materials surface vibrate for short periods of time and emit through a light wave
Reflection
Light bounces off things
Reflection of light off surfaces
Rays go towards the eye - arrows represent the way the light travels
Refraction
Light is made up of different colours
Depending on its wavelength when it moves through different materials
Is white a colour?
Materials have frequencies
Colour comes from natural frequencies
White is a combination of colours
Primary colours for mixing light are red blue and green
The 7 colours on the spectrum- how to remember them
Red Orange Yellow Green Blue Indigo Violet
Richard York Gave Battle In Vein
Does light or sound travel faster?
Light travels faster than sound
What are shadows
Shadows occur when a path of light is blocked by the object
Shadow is formed on the opposite side of the object to the light source
Closer the object - the larger the shadow
Shadows never vanish
3 parts of a battery
Cathode (+)
Electrolyte (conducts electricity when dissolved in water)
Anode (-)
How does a battery work
Chemical reaction causes a build up of electrons at the anode
The charges repel
When the circit is closed (a wire connects the cathode and anode) the electrons will be able to get to the cathode by going through the wire
Wires
Electrons will leave valence shell because metal is a better conductor
Circuit - all electrons move in same direction
Battery
Contains chemicals which have chemical energy. When the chemicals react with each other they generate electrical energy. The battery is a source of electrical energy and provides the push to make the electrons move
The electrons carry the electrical energy from the battery to the bulb - energy transfer
The bulb changes electrical energy into light and heat energy - transformation
Push
Voltage
Energy transfer
‘Conga line’ analogy
Transformation
Electrical energy to light and heat energy
Electrical conductors and insulators
Materials contain free electrons that can move around (conductors)
Conductors allow the passage of electrical current
Conductor is an atom that does not hold onto its valence electrons well
Insulators do not want to join
Conga line analogy
Valance electrons will not move from atoms
Solar energy
Both light and heat energy
Heat energy from the sun transferred to electricity (solar panels)
Wind energy
When the sun heats up the atmosphere - air moves and it creates wind
Wind turbines
Water energy
Hydroelectricity
Tidal energy
Wave energy
Geothermal energy
Energy from earths crust
Balanced forces
Balanced forces do not change motion - they have the same effect as if there were no forces involved
When forces are balanced - the motion of object is unaffected
Unbalanced forces change the motion of objects
What is gravity
Gravity is a non contact force
Force of attraction
Force of attraction depends on the objects mass or how close the objects are to each other
Mass
Mass is the same on earth or moon
Weight
Depends on gravitational force and varies throughout the universe
Gravity and space
Gravitational force depends on the mass of the planet
Larger the mass of the planet the greater the gravitational force will be
Inertia
The resistance of any physical object to change in its state of motion, including changes to speed or direction
