P1 - The Earth in the Universe

Question 1

How old is the Earth?

Answer 1

4500 million years old.

Question 2

How old is the Solar System?

Answer 2

5000 million years old.

Question 3

How old is the Universe?

Answer 3

1400 million years old.

Question 4

How many years older is the Sun than the Earth?

Answer 4

500 million years older.

Question 5

Can you name the 6 ways scientists can use rocks as evidence of the Earth’s age?

Answer 5

• Erosion - Compacted layers, produced by weathering and erosion. Older layers at the bottom.
• Craters - Evidence on Moon, not on Earth due to erosion.
• Mountain formation - If new mountains weren’t being formed, the Earth’s surface would have eroded down to sea level.
• Folding - Folding rocks requires huge force over a long time.
• Fossils - Shows how life has changed.
• Radioactivity - Lower radioactivity means older.

Question 6

What is the Earth’s core made from?

Answer 6

Nickel and iron.

Question 7

How is the Earth’s core still hot?

Answer 7

From the decay of radioactive elements.

Question 8

Why was Wegener’s theory not immidiately accepted?

Answer 8

• He wasn’t a geologist, and was seen as an outsider.
• The supporting evidence was limited.
• It could be explained more simply. e.g: A bridge connecting continents could have eroded over time.
• The movement of the continents wasn’t detectable.

Question 9

What is a geohazard?

Answer 9

A natural hazard.

Question 10

How often does the Earth’s magnetic field change polarity?

Answer 10

Every million years.

Question 11

Which plate is denser? Oceanic or continental?

Answer 11

The Oceanic plate is denser.

Question 12

How are metamorphic rocks formed?

Answer 12

When due to extreme heat, the minerals in sedimentary or igneous rocks are changed chemically.

They do not melt however, that would form an igneous rock.

Question 13

If a wave is travelling at a constant speed…

If frequency increases, the wavelength will _________.

Answer 13

If frequency increases, the wavelength will decrease.

and vice-versa (If frequency decreases, wavelength will increase).

Question 14

If a wave is travelling at constant frequency…

If the wave speed decreases, the wavelength will _________.

Answer 14

If the wave speed decreases, the wavelength will decrease.

and vice-versa (If wave speed increases, the wavelength increases).

Question 15

What are the units for wave speed?

Answer 15

m/s.

Question 16

What are the units for frequency?

Answer 16

Hz.

Question 17

What are the units for wavelength?

Answer 17

m.

Question 18

What are the units for distance?

Answer 18

m.

Question 19

What are the units for time?

Answer 19

s/secs.

Question 20

How was the Solar System formed?

Answer 20

1. The solar system started as dust and gas clouds, pulled together by gravity.
2. This created intense heat and nuclear fusion began, hence a star was born! That’s the sun by the way…
3. The remaining dust and gas formed smaller masses, which were attracted to the sun.

Question 21

Name the 5 smaller masses of our solar system.

Answer 21

• Planets.
• Moons.
• Asteroids.
• Comets.
• Dwarf planets.

Question 22

Compare asteriods and comets.

Answer 22

Asteroids are rocky and comets are icy.

Question 23

What shape are orbits?

Answer 23

They are elliptical.

Comets are highly elliptical.

Question 24

What is the speed of light?

Answer 24

The speed of light is 300,000km/s through space (a vacumn).

Question 25

How does **relative brightness** work?

Answer 25

**Further away stars are dimmer**. *However, brightness can vary so a star's distance is never certain.*

Question 26

How does **Parallax** work?

Answer 26

**Stars in the distance appear to move _against the background of distant stars_**. **Closer stars appear to move more through parallax**. In Parallax, **two measurements are taken** - an **initial measurement and another 6 months later** *(e.g: Jan - July)* to try and get the **actual position of a star** using the **opposite sides of orbit**. You are measuring the **parallax angle**. **Greater distance = Smaller parallax angle**. *However, the further away a star, the less accurate the measurement is.*

Question 27

How long does it take for **light to reach Earth from the Sun**?

Answer 27

Rougly **8 minutes**.

Question 28

Explain how **Hubble's Law** works.

Answer 28

Hubble's Law states: *"The speed at which a **galaxy is moving away** is **proportional** to its **distance from us**"* If all of the galaxies are moving away from us, then this must mean that the **Universe is expanding**. - Sources of light **further away from us have a longer wavelength**, and are **red shifted**. Wavelengths of light from nearby galaxies are **longer than scientists expect**, which means they must be **moving away from us**.

Question 29

**The Universe keeps expanding when there isn't enough mass**. What will happen if there is **too much mass**?

Answer 29

**Gravity will put everything back together** and the Universe will **collapse**.

Question 30

What are the **3 layers of the Earth** called?

Answer 30

* **Crust**. * **Mantle**. * **Core**.

Question 31

Explain **Seafloor Spreading**.

Answer 31

**Seafloor Spreading** is where **convection currents** in the **mantle** cause **magma** to rise. These currents **move** the solid part of the mantle and the tectonic plates. When the plates move apart, magma reaches the surface and **hardens**, forming new areas of **oceanic crust** *(Seafloor)* and pushing the existing floor **outwards**. New crust is **continuously forming**.

Question 32

**Compare P and S waves**.

Answer 32

**P-waves** are **Longitudinal**. **S-Waves** are **Transverse**. *(Cloest in alphabet).* The **fastest** wave: **_P_-Waves** *(**_P_**hast)*. The **slowest** wave: **_S_-Waves** *(**_S_**low)*. Solid **only** wave: **_S_-Waves** *(**_S_**olid)*. The **first** wave: **_P_-Waves** *(**_P_**rimary)*. The **second** wave: **_S_-Waves** *(**_S_**econdary)*.

Question 33

**Label** the wave below.

Answer 33

Question 34

What types of **radiation** do **stars** produce?

Answer 34

* **Visible light**. * **Ultraviolet**. * **Infrared**.

Question 35

As stars get **further away**, their **wavelength** of visible light gets **\_\_\_\_\_\_\_\_**.

Answer 35

As stars get **further away**, their **wavelength** of visible light gets **larger**.

Question 36

How much of the Solar System's mass is the **Sun**?

Answer 36

**99%**.

Question 37

What is the **heaviest planet**?

Answer 37

**Jupiter**.

Question 38

What **planet** has the **largest orbit**?

Answer 38

**Neptune**.

Question 39

Why is the **fate of the universe difficult to predict**?

Answer 39

Because we can **only measure the mass of those parts of the Universe which emit radiation** and **radiation travels such a long way to get to us, so precise measurements can not be made**.

Question 40

What is the **principal frequency**? What **factor** causes it to **increase**?

Answer 40

**Radiation with the greatest intensity**. **Heat** causes it to increase.