Physics P2 Ocr Gateway (2)

Front 1

How do you protect yourself from radioactive sources?

Back 1

- Keep in labelled lead boxes
- Keep exposure time short
- Handle with tongs
- Never allow skin contact = arm's length away

Front 2

If you work with nuclear radiation, how are you protected from radioactive sources?

Back 2

- Wear full protective suits: prevent inhalation, on skin or under nails
- Lead lined suits, lead barries and screens shield from gamma in highly radioactive areas
- Workers use remote controlled robot arms to carry out tasks

Front 3

How is "low level" radioactive waste disposed of? (from nuclear power stations and hospitals)

Back 3

Burying

Front 4

How is high level radioactive waste disposed of and why?

Back 4

Glass blocks inside metal containers buried deep under ground because they stay highly radioactive for thousands of years

Front 5

Why are there limited places to where high level radiation can be buried?

Back 5

- Has to be geologically stable (prevent leaks)
- Cannot be near ground water (prevent contamination)

Front 6

What does our solar system consist of?

Back 6

Planets, stars, comets, meteors, galaxies and blackholes

Front 7

What is the order of the planets?

Back 7

Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune

(My very easy method just speeds up naming (planets)

Front 8

What is the solar system held together by?

Back 8

Gravitational attraction

Front 9

What caused the asteroid belt to form?

Back 9

The rocks between Mars and Jupiter didn't form a planet as the large gravitational attraction of Jupiter kept interferring and so they are left asteroids that orbit the sun between the orbits of Jupiter and Mars

Front 10

What are meteors?

Back 10

Rocks or dust that enter the Earth's atmosphere

Front 11

What happens as meteors pass through the atmosphere?

Back 11

They burn up and we see them as "shooting stars"

Front 12

What may happen if all the meteor doesn't burn up?

Back 12

It may crash into the Earth's surface as a meteorite

Front 13

What effects can a meteorite cause?

Back 13

Fires, hot rocks, dust, craters
The dust and smoke can block sunlight out for many months causing climate change = species become extinct

Front 14

What 3 kinds of evidence are there to show that asteroids have collided with Earth in the past?

Back 14

1. Big craters
2. Layers of unusual elements in rocks
3. Sudden changes in the number of fossil numbers as species suffer extinction

Front 15

What are comets? What are their orbits like?

Back 15

Balls of rock, dust and ice that orbit the sun in elongated ellipses

Front 16

What happens as a comet approaches the sun?

Back 16

Its ice melts, leaving a bright tail of gas and debris.
They speed up because the sun's gravitational pull increases as you get closer

Front 17

What are NEO's? (Near Earth Objects)

Back 17

Asteroids or comets which might be on a collision course with earth

Front 18

Why can NEO's be difficult to spot?

Back 18

They're small, dark and may have unusual orbits

Front 19

How could you deflect an NEO before it hit Earth?

Back 19

Explode a bomb close to it to knock it off its course

Front 20

Describe the formation of the Moon
(3 points)

Back 20

1. Formed when another planet collided with Earth
2. In the heat of the collision, the dense iron corsed merged to form the Earth's core
3. The less dense material was ejected as hot dust and rocks which orbited and eventually came together to form the Moon

Front 21

Give 2 pieces of evidence that support this theory of the Moon's formation

Back 21

1. The Moon has a lower density than Earth and doesn't have a big iron core like Earth
2. Moon rocks contain few substances that evaporate at low temperatures = must be formed from hot material

Front 22

What is a light year?

Back 22

The distance that light travels through a vacuum in one year

Front 23

Give 4 properties of black holes?

Back 23

- Large mass
- Small volume
- High density
- Not visible (light cannot escape their gravitational pull)

Front 24

What are some advantages of sending manned spacecract to space? (2 points)

Back 24

- Can carry out as many experiments as necessary
- Can use senses/collect samples

Front 25

What are some disadvantages of sending manned spacecraft to space? (6 points)

Back 25

- Carry food, water and oxygen
- Expensive
- Low gravity causes muscle wastage and loss of bone tissue
- Psychologically stressful
- Have to be shielded from radiation
- Temperatures need to be regulated and toxic gases removed

Front 26

What are some advantages of sending unmanned probes to space? (4 points)

Back 26

- Don't carry water, food or oxygen
- Can withstand conditions humands can't
- Cheaper
- No one is harmed if something goes wrong

Front 27

What are some disadvantages of sending unmassed probes to space? (2 points)

Back 27

- Have to be programmed and cannot think for themselves
- Cannot be repaired if something goes wrong

Front 28

How is data from distant objects sent back to Earth?

Back 28

"beamed" back as it would to take too long for the spacecraft to travel back to Earth

Front 29

How is data from nearer objects sent back to Earth?

Back 29

Probes or people could collect samples and physically bring it back for analysis

Front 30

Why is the universe increasing in size?

Back 30

Galaxies are moving away from each other

Front 31

What do measurements of red-shift suggest?

Back 31

That all distant galaxies are moving away from us very quickly

Front 32

Do distant galaxies show more or less red-shift? What does this mean?

Back 32

More
Means that they are moving away faster than nearer ones = the whole universe is expanding

Front 33

What does cosmic background radiation show?

Back 33

Evidence for an initial big bag, as the universe expands and cools, tis background radiation "cools" and drops in frequency

Front 34

What do red-shift and cosmic background information prove evidence for?

Back 34

The Big Bang

Front 35

What is the theory of the Big Bang?

Back 35

1) All the matter of the Universe was concentrated into a very small space
2) It then exploded and the space started to expand, and still continues to

Front 36

What does the rate of expansion allow us to do?

Back 36

Estimate the age of the universe

Front 37

Why is it difficult to estimate the age of the universe?

Back 37

It's hard to tell how much speed of the expansion has changed since the Big Bang

Front 38

What is the end of the life cycle for a small star?

Back 38

Red giant, planetary nebula, white dwarf

Front 39

What is the end of the life cycle for a large star?

Back 39

Red supergiant, supernova, neutron star or blackhole

Front 40

Briefly describe the life cycle of a star

Back 40

1. Interstellar gas cloud
2. Gravitational collapse producing a proto star
3. Thermonuclear fusion
4. Long period of normal life (main sequence)
5. End depends on mass of star

Front 41

What was Copernican's (Heliocentric) model of the solar system?

Back 41

- The sun is at the centre of the universe and the planets orbit it with a circular orbit

Front 42

What evidence did Galileo find related to Jupiter?

Back 42

He saw stars that never moved away from Jupiter and seemed to be carried along with the planet which suggested they were moons orbiting Jupiter. This showed that not everything was in orbit around the Earth (Roman Greek Plotemaic model was wrong)

Front 43

What evidence did Galileo find related to Venus?

Back 43

Venus has phases where the amount of the planet that's lit by the Sun seems to change over time. Supported Copernican model because Venus would move in front of and behind and so the changes in the amount by which Venus was lit would change dramatically = what he saw

Front 44

What was the Copernican model not accepted at the time?

Back 44

- The current models had been around for a long time
- Condemned by the Church because it went against the Bible which said Earth was at the centre

Front 45

What model is accepted now?

Back 45

The planets orbit the Sun but these orbits are elliptical rather than circular