finals exam Flashcards
heat
heating of substances occurs the particles that make up the substance begin to move faster creating kinetic energy. when this happens particles move apart making the substance expand.
cooling
when cooling a substance the particles lose kinetic energy and move close together making the substance condense
radiation
Transfer of energy through electromagnetic waves Does not involve any particles Does not require contact between the object and heat source. an example is a microwave.
mechanical waves
waves that need a material medium to transfer energy (propagate). they transfer energy through the oscillation (back and forth) of particles in a medium. E.G. water and air
electro magnetic waves
electro magnetic waves are transverse self propagating waves that can travel without a medium. these waves all travel at the speed of light in a vacuum.
reflection
when light hits a shiny surface most of it bounces off. E.G. mirrors.
refraction
is the bending of light that occurs because light travels at speeds through different media (plural medium). light tries to escape the normal if the new medium slows down, the light will bend to the medium.
transparent
something that is clear and allows light to pass through it
translucent
material that allows most light to pass through showing the objects behind but unclearly.
opaque
a material that can not be seen through does not allow light to pass through.
colour
colours all come from white light and the colours we see are certain wavelengths that come from white light that bounce off certain surfaces to reflect light and that is the colour we see
measuring waves
wave equation V=Fλ (wave length)
V is the speed of the wave in m/s
F is frequency in Hz (herts)
λ is wave length in m
convex lenses
a lense that bulges outwards is known as a convex lense. these lenses cause light rays to a point called the focus. the distance between the middle of the lense and the focus is known as the focal length the stronger the lens the shorter the focal length.
concave lenses
a lense that curves inwards are known as concave lenses.these causes light rays to diverge and spread out. they parallel light rays as though the rays come from a point behind the lense
eye structure (front)
- cornea - strong clear lining at front of eye that bends light into the lens
- lens - biconvex lens that focus on the light on the retina.
- aqueous humour - lies between cornea and lens, clear watery fluid produced by ciliary body that lubricates the cornea and lens.
4.pupil - opening the eye that determines amount of light that enters. - iris - the coloured part of the eye that contains dilator and sphincter muscles, muscles that control the pupil opening.
structure in the eye (middle)
- ciliary body - connected to the lens and contains muscles that change shape of lens to ensure light is refracted optimally.
- vitreous humour - clear fluid (jelly like) that fills the middle part of the eye.
structure of the eye (back)
- retina - contains cells that absorb light and turns them into electrical signals.
- optic nerve - carries the electrical signal to the brain
sound
caused by vibrations when the vibrations pass through the ear they bunch together causing something called compressions and then regions of air particles to spread out called rarefactions. loud sounds have larger amplitude, the higher pitched the sound the higher frequency and lower wave length.
structure of the ear
- pinna
- auditory canal
3.eardrum - hammer anvil stirrup
5.semicircular canals - cochlea
- auditory nerve
- eustachian tube
absorbing sound
soft materials such as curtains absorb sound and convert it to heat. reducing the echo and sound of something
electricity
electrons are not tightly bound to an atom so they move around freely. especially within conductors the flow of electrons within a wire is called electricity.
series circuit
series circuits have only one path for electrons to flow through but the more components less amount of energy each component has. they share voltage. also whole series stops working if one component fails as flow of electrons stop.
parallel circuit
parallel circuits have more than one path and components are connected together and have the same amount of energy throughout the circuit. each branch gets full amount of voltage from power source. they continue working if one branch stops working also.
voltage
the amount of of energy given to the electrons.
AC current (alternating current)
alternating current (AC) - the flow of current alternating back and forth multiple times. AC is mainly used for large appliances that require lots of power, AC currents can also travel further distances
DC current (direct current)
direct current (DC) - direct current only goes one direction mostly used for portable electronics which require batteries.
fuses
when a circuit allows too much current to flow through it it can heat up and lead to fires. to prevent such things fuses are used in circuits and are are designed to burn and break the circuit once high current is reached. a fuse is a conductor with a high resistance and a low melting point.
circuit breakers
same thing as a fuse but allows the circuit to be restored with a switch. a switch has to be flicked to manually restore normal function to the circuit.
earth wires
3 prongs of a plug have 3 wires conducted to them. active wire - carries current to the powerpoint. neutral wire - carries current away from power. Earth wire - connects the power to the Earth beneath this prevents current traveling through you.
energy efficiency
every transfer has some non-useful component, hence its efficiency is never at 100%. useful output of energy/input energy x100
earth structure
crust - 0-100 km thick
mantle - 2800 km thick
outer core - 2200 km thick
inner core - 1200 km radius
surface to core - 6378 km
continental drift
in 1912 a german scientist Alfred wegener proposed the idea of continental drift. the idea was that the whole world was joined together as one land mass called Pangea
ocean ridges
scientists in 1872 found that the ocean floor had vast underwater ridges/mountain ranges, extended across the ocean. these ridges have huge cracks along them called rifts
seafloor spreading
in 1960 Harry Hess proposed that new crust came from the ocean ridges and was spreading outwards.
earthquakes
the event of two chunks of Earth trying to slip past each other, building up and storing energy then when one of them finally overcomes the other immense energy is released.
fault/fault plane
the location of the slip on the surface
hypocenter
location below the earths surface where the earthquake occurs
epicenter
location above the earths surface
measuring earthquakes
scientists use a seismometer to read the level of the energy and danger of the earthquake
seismic waves
the movement of the ground in an earthquake occurs in a back and forth motion called seismic waves theres 3 types:
1. primary waves (P-wave) - up and down, and travel fast
2. secondary wave (S-wave) - sideway, slighter slower than P-waves
3. surface wave - slow but most powerful, on the crust
diverging boundaries
where plates are moving away from each other together
converging boundaries
when two plates overlap one going below the other what happens from this depends on the type of plates:
continental + oceanic = oceanic sink sinks below continental forming a volcano
oceanic + oceanic = faster moving one sinks under forming very deep trenches
continental + continental = none sink below they collide and form very high mountains
transform boundaries
when plates slide parallel in opposite directions. usually happens slowly but the plates slip, moving quickly causing earthquakes.
ion
an atom that has lost or gained electrons depending on the number of valence electrons
ionic
when atoms donate electrons to another atom they form a ionic bond the atoms combine creating a compound, this happens between non-metals and metals
polyatomic ions
consists of many atoms and have an overall net charge which can also combine with atoms to form ionic compounds
acids
a substance that release hydrogen ions (H+) into a solution (water). Hydrogen ions are Hydrogens atoms without an electron. acids are made up of different elements. acids strength rely on the amount of H+ they release. properties include corrosive, sour taste, reacts with metals to form hydrogen leaving salt behind, conducts electricity, neutralized by base, making salt water. PH level is 0-6
bases
they release hydroxide ions (OH-). the more OH- the more basic the. if the base can dissolve in water it is a alkali. when dissolved the solution is called alkaline. properties include, caustic (they burn), soapy slimy feel, bitter taste. PH level is 8-14
neutralisation
acids and bases can cancel each other out if given the same amount of each other creating water.
metals
properties include:
malleable, lustrous, ductile, conduct electricity, thermal conductors.
pure metals
metals without any other substance. E.G. the metals on the periodic table
Alloys
Metals that have been combined with other substances. we do this to strengthen and add beneficial properties
non-metals
found on right side of periodic table. poor conductors of electricity, many of them are gasses, if solid usually brittle.
carbon allotropes
carbon is a unique element that can exist as different forms. these different form is called allotropes and depends on the carbon structure. E.G diamonds - can be created under high pressure and heat, carbon atoms arrange themselves in a cubic structure.
metalloids
elements halfway between being a metal and a non-metal, are decent conductors of heal and electricity, usually solids at room temp, shiny like metals
