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OCR GCSE Science P1
OCR 21st Century Science P1
Question | Answer | ||||
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The sun and the objects that orbit it (i.e planets, dwarf planets, asteroids, comets and moons [which orbit planets]) make up the | solar system. | ||||
A planet is an astronomical object that o[] a [] | orbits a star, and has sufficient mass to assume a nearly [] shape | round--. | |||
The natural satellite of a planet is called a | moon. Moons often have roughly circular | orbits. | |||
The star at the centre of the solar system is the | Sun. In terms of movement, the Sun is | stationary. | |||
A celestial body with a nucleus of ice and dust, that produces dust and gas as it nears the sun is a | comet. Comets spend a lot of time far from the [] due to their [...] | sun due to their elliptical orbits. | |||
An asteroid is a mass of [] and [] that orbits a [] | rock and metal that orbits a star. | ||||
Comets spend a lot of time far from the sun. They plunge [] to pass around the [] | inwards to pass around the sun, then return to the cold outer reaches of the | Solar System. | |||
Apart from material, another difference between asteroids and comets, is that while asteroids have orbits that are roughly | circular, comets have orbits that are | elliptical. | |||
Order in size (smallest to biggest): planets, moons, the Sun, comets and asteroids - | comets, asteroids, moons, planets, the Sun. | ||||
The solar system was formed over [] periods | long periods about [...] ago | 5000 million years ago. | |||
The solar system was formed over long periods from [] of [] and [] | clouds of gases and dust in space. | ||||
The Sun is one of []s of []s of []s | thousands of millions of stars in the [] [] galaxy | milky way--. | |||
Galaxies number []s of []s | thousands of millions, and all of these galaxies make up the | Universe. | |||
Each galaxy contain []s of []s of stars | thousands of millions--. | ||||
Put in order the following (from smallest to biggest):the distances from the Milky Way to the nearest other galaxy, the sun to the nearest other star, the diameters of the solar system, Earth's orbit, the Sun, the Earth and the Milky Way | diameter of Earth, diameter of Sun, diameter of Earth's orbit, diameter of solar system, Sun to the nearest other star, diameter of the Milky Way, the Milky Way to the nearest other galaxy. | ||||
'All the evidence we have about distant stars and galaxies comes from the [] astronomers can detect | radiation--.' | ||||
Light travels through space (in a vacuum) at a finite speed of approximately | 300,000 km/s | ||||
The distance that light travels in one year (with the speed that light travels in a vacuum) is called a | light-year. | ||||
The finite speed of light means that very distant objects are observed as they were in the | past, when the light we now see [] them | left--. | |||
Parallax provides a way of measuring | distances. | ||||
Using relative brightness: with two stars, the one that appears brighter is the one that's | closer, but such comparison should only be used if the two stars are | the same type. | |||
Observations of the night sky can be interfered with by [] pollution and other []ic conditions | light pollution and other atmospheric conditions. | ||||
There are uncertainties about the distances of stars and galaxies due to the nature and difficulty of the [] and the [] made in interpreting them | observation (things may appear not as they are)--assumptions--. Each Method has built-in assumptions and methods can depend on the []s of previous ones | results--. [#P2#] | |||
The brightness method assumes that two stars that appear similar are | the same type of star. | ||||
The source of the Sun's energy is the | fusion (joining) of hydrogen nuclei. Hydrogen nuclei fuse to make | helium. | |||
Joining small nuclei together releases [] and creates new [] | energy--elements--. This process is called | nuclear fusion. | |||
Nuclear fusion happens only at extremely [] temperatures | high temperatures - millions of degrees (the temperature inside a star). | ||||
All chemical elements with atoms heavier than helium are made in | stars through | nuclear fusion. | |||
When astronomers looked at light from distant galaxies, they saw that their spectrum was shifted towards the | red end. This is called | redshift. | |||
The amount of redshift in the spectrum of the light from galaxies shows how [] the galaxies are [...] | how fast the galaxies are moving away. In general, the further away a galaxy is: [...], [] [] us. | the faster it is moving, away from us. | |||
Galaxies moving away from us suggests that space itself is | expanding: taking the assumption that we don't have a speciall place in the universe, it suggests that everything is [] [] [] everything else | moving away from--. | |||
The relative ages, from youngest to oldest, for the Earth, Sun and Universe: | Earth, Sun, Universe. | ||||
Scientist believe that the Universe began with a '[] []' | 'big bang' about | 14 billion years ago. | |||
The ultimate fate of the Universe is difficult to predict because of difficulties measuring the large [] involved and the [] of the universe | large distances involved and the mass of the Universe, and studying the studying the [] of very distant objects | motion--. | |||
Sediments are [] and [] to form sedimentary rocks | compressed--cemented. In some places,layers of sedimentary rocks are t[] or f[] | tilted or folded. | |||
Rivers carry sediment to the | oceans, where it settles at the [] as [] and [] | buttom as sand and silt. | |||
Sedimentary rocks are made from [] material | eroded. | ||||
James Hutton connected the observations that soil was washed away and many rocks are made up of eroded material with the idea of a | cycle - continents are both | eroded and created. | |||
What Hutton described in his theory is the rock | cycle. What takes place is [] and [] of sediment, which happens (in terms of time) very [] | erosion--deposition [--sedimentation]--slowly. Over enormous periods of time, these processes add up to huge changes in the Earth's | surface. Erosion makes new | soil (and is therefore considered essential to human survival). Heating inside the Earth changes [] and lifts [] up | rocks and lifts lands up. |
One way that geologists try to find evidence of change in rocks in the Earth is by looking at layered rocks in which the deeper rocks tend to be | older - in layered rocks, the younger rocks are usually on top of [] ones | older--. | |||
One way that geologists try to find evidence of change in rocks in the Earth is by using [] as 'time markers' | fossils--, as it is thought species existed at particular [] | times, then later became extinct. | |||
One way that geologists try to find evidence of change in rocks in the Earth is by looking at cross-cutting features: if one type of rock cuts across another rock type, it is | younger. For example, hot magma can fill cracks and solidify as | rock. | |||
If mountains were not being continuously formed, continents would be worn down to [] level by [] | sea level by erosion. | ||||
There is a match in both the fossil [] and the reptile [] from both Africa and South America | plants--fossils--. This is taken as evidence for []'s theory of [...] | Wegener's theory of continential drift. | |||
Rock processes seen today can account for past | changes. | ||||
The age of the Earth can be estimated from and must be greater than the age of its | oldest rocks, which are about | four thousand million years old. | |||
Across the continents, there are matching [] and rock [], and there is a [] fit of continents | fossils--layers--geometric. This is taken as evidence for []'s theory of [...] | Wegener's theory of continential drift. | |||
Wegener's theory of Continential drift proposed that the continents are | moving and had once been | joined together. | |||
Wegener suggested that mountains were formed when the [] of a [] continent ... | when the edge of a drifting continent collided with another, causing it to c[] and f[] | crumple and fold. For example, the Himalayas were formed when India came into contact with Asia. | |||
The theory of Continential drift proposes that the single landmass began to crack and divide, due to the slow currents of [] beneath it | magma--. | ||||
Reasons for the rejection of Wegener's theory by geologists of his time include: the movement of the continents was not | detectable, it was too big and idea from limited | evidence, there were similar explanations of the same | evidence, and Wegener was an outsider to the [] of geologists | community--. | |
Under most oceans is a chain of [], now called an ... | chain of mountains, now called an oceanic ridge. | ||||
It is considered that the seafloor moves away from either [] of an ... | either side of an oceanic ridge. This process, called [] [], could [] continents | seafloor spreading could move continents. | |||
Seafloor spreading: beneath a ridge, material the Earth's [] [] rises slowly | solid mantle rises slowly. As it approaches, the ridge, pressure | falls. So some of the material melts to form | magma. Movements in the [], caused by [], pull the ridge apart, like conveyor belts | mantle--convection--. Hot magma [] and [] to make new [] | Hot magma erupts and cools to make new rock. |
Sea floor spreading is caused by c[] []ts in []a | convection currents--magma--, which in turn is caused by []ing from the [] | heating--core--. | |||
Per year, the seafloor spreads by [...] | a few centimetres. | ||||
There is a peroidical [] of the Earth's magnetic field | reversal--. The magnetic north pole becomes the south pole and vice versa. | ||||
Fred Vine explained the identical strip pattern found in rock magnetism on either side of | oceanic ridges. Vine said that if hot magma rises at a ridge and cools to make new rock, then the rock will be magnetised in the direction of the Earth's [] [] at the [] | Earth's magenetic field at the time (this paired with the knowledge of the periodic reversal of the magnetic field give an explanation). [#P3]. | |||
Eathquakes, volcanoes and mountain building generally occur at the edges of | tectonic plates. | ||||
In some places tectonic plates slide past each other. The shoving of the Earth's plates causes forces to build along the | fault lines. Eventually the forces are so great that the rocks that are [] together [] | rocks locked together break, and allow plate movement. The ground [], causing an [...] | shakes, causing an earthquake. | ||
Earthquakes are common at all moving | plate boundaries. | ||||
Mountains are caused to form by collisions between | tectonic plates. There are three ways that this can happen. | ||||
Way mountains may be formed (1): where an oceanic plate dives into the | mantle, [] peaks may form at the [] | volcanic--surface. | |||
Way mountains may be formed (2): if there is a [] movement at [] margins | pushing movement at destructive margins, rocks could be caused to b[] and f[], forming a ... | buckle and fold, forming a mountain chain. | |||
Way mountains may be formed (3): sometimes an [] closes completely, and two [] collide in slow motion | ocean--continents--. The edges of the continents c[] together and p[] up, making ... | crumple together and pile up, making mountain chains. | |||
The name given to a zone where a tectonic plate has dived downwards is called | a subduction zone. | ||||
In the rock cycle: rock is carried down into a [] zone, where it partly [] | subduction zone, where it partly melts. This may later solidify as | igneous rock.[#P4]. | |||
Earthquakes produce [] motions on the [] and [] the Earth | wave motions on the surface and inside the Earth which can be detected by instruments located on the Earth's | surface (e.g a seismometer). | |||
P-waves are [] waves | longitudinal waves, which travel through [] and [] | solids and liquids. | |||
S-waves are [] waves | transverse waves, which travel through [] but not [] | solids but not liquids. | |||
Longitudinal waves travel as a series of | compression; they [] then [] | compress then release. | |||
In transverse waves the vibrations are at [] []s to the direction of travel | right angles--. (The travel is like rope when one moves the end of a rope up and down.[#P5#]) | ||||
As waves travel, they set up patterns of | disturbances (the lines). The amplitude is the maximum [] from its [] position | distubance from its undisturbed position. [#P6#]. | |||
Between P-waves and S-waves, the type that arrives at the detector first is | P-waves.{In P-waves: 'P' stands for [] and in S-waves: 'S' stands for [] | primary--secondary--. | |||
From a pattern of reflected waves, geologists can work out the structure of the underlying | rocks. | ||||
Scientist noticed that both P-waves and S-waves reached seismometers close to the earthquake centre, but the only one that reached seismometers far off, on the other side of the Earth was the | P-waves (there was a large 'shadow zone' where S-waves never reached). | ||||
Using the differences in the behaviour of P-waves and S-waves, Beno Gutenberg proposed that the 'shadow zone' was due to S-waves being blocked by the | liquid core. [#P7#]From the size of the shadow zone, he was able to work out the size of the | core (700km - half the earth's diameter). (PS: by looking at the pattern of P-waves, someone deduced that there must be a small, solid core inside the liquid core.) | |||
In relation to waves: distance (m) = | wave speed (m/s) x time (s) | ||||
The frequency of waves, in hertz (Hz), is the number of [] that the source makes each second | waves--(1 Hz means 1 wave per second). It is also the number of WAVES that pass a certain [] each second | point--. | |||
The distance that it takes for a wave to repeat itself (i.e the distance between the corresponding points on two adjacent cycles) is its | wavelength. | ||||
[#P8#]Draw and label a diagram of the Earth to show its crust, mantle and core. | |||||
A wave is a d[], caused by a [] source | disturbance, caused by a vibrating source, that transfers [] in the direction that the wave travels without transferring [] | energy--matter--. | |||
The speed at which each wave crest(the pinnacle) moves is called the | wave speed and is measured in | metres per second (m/s). | |||
wave speed(m/s) = | frequency(Hz) x wavelength(m). Thus, for a constant wave speed, the wavelength is inversely proportional to | the frequency. | |||
A destructive plate boundary happens where | a oceanic and continental plate move towards each other. The heavier, denser | oceanic plate is forced [] the continental plate | under--. As it sinks below the continental plate, the oceanic plate [] due to [] in the subduction zone | melts--friction--. The crust becomes [] called [] | molten called magma. |
A comet has a nucleus of [] and [] | ice and dust and produces [] and [] as it nears the sun | dust and gas. | |||
As an S-wave travels, the material of the Earth moves from | side to side. | ||||
The amount of planets in the solar system is | eight. The eight planets in the solar system move around the [] in almost [] paths | sun in almost circular paths. | |||
[#P1#] In six months, the Earth moves from one side of the Sun to | the other. At the start and end of the six months, seen through a telescope on | Earth, a [] star will shift its position | nearby-- against the background of more | distant stars. This effect is called | Parallax. |
With Parallax, the more a star shifts, the [] it is | nearer--. |