chapter 6 sound and space

Question 1

How does a sound wave travel through the air?

Answer 1

A sound wave travels through vibrations of particles

Question 2

what is the amplitude of a sound wave?

Answer 2

The amplitude of the sound wave is the distance from the starting point to the peak/trough, it is also how loud a sound wave is

Question 3

what is the frequency of a sound wave, and what is the unit?

Answer 3

how many waves per second it is measured in Hz (hertz)

Question 4

what is subduction

Answer 4

when a tectonic plate gets pushed under another plate and melts into the magma

Question 5

what is the pitch of a sound wave?

Answer 5

the pitch is how frequent a wave is (the more frequent the higher pitch)

Question 6

what is the wavelength of a sound wave

Answer 6

it is the distance between the same points on neighboring waves

Question 7

what is the peak and trough of a sound wave

Answer 7

the peak is the highest point on a wave from the starting position, and the trough is the opposite

Question 8

what do waves need to do to reinforce or cancel

Answer 8

to reinforce two waves need to meet with their peaks and troughs together and to cancel the peak and trough wouldn’t meet

Question 9

what planet was theia close to in size?

Answer 9

mars

Question 10

what happened in the collision theory (3)

Answer 10

1. theia and earth collided sending debris into space
2. the debris formed a ring around earth
3. the debris coalesces and form the moon

Question 11

state two pieces of evidence that support the collision theory

Answer 11

1. the collision theory fits with how the theory of how the solar system was formed
2. the composition of rocks on earth and the moon are the same

Question 12

state two pieces of evidence that go against the collision theory

Answer 12

1. if this happened the moon’s rocks should be more similar to theia’s
2. Venus has no moon and if the collision theory was true it should be expected to get one in the same way as the moon

Question 13

what is a nebula

Answer 13

a nebula is a cloud of dust and gas in a galaxy

Question 14

what is a stellar nursery

Answer 14

a stellar nursery is a part of a nebula that forms new stars

Question 15

how are stars formed
(come back to this when millie isnt watching me)

Answer 15

a star is formed inside a stellar nursery as gravity brings together dust and gas and reacts to make a star

Question 16

what is the most common in a nebula

Answer 16

Helium and hydrogen

Question 17

why are younger stars harder to see then older ones

Answer 17

they are harder to see because when a star is first formed the dust and gas are not compressed a lot and so they produce less light and heat, but as time goes by gravity pulls the star closer together which makes more reaction which makes it hotter and brighter

Question 18

how does the fossil record support the Pangea theory and what was another idea for it that was turned down later

Answer 18

• fossils on two different continents have matched up meaning that they could have been together and shared the same animals
• some people thought that there could have been a land bridge between continents but it is not possible

Question 19

what is the Pangea theory

Answer 19

that the continents used to be one and all fit together like a jigsaw puzzle.

Question 20

what is a tectonic plate

Answer 20

pieces of land that make up the earths crust

Question 21

what is the convection current and how does it move the continents

Answer 21

the convection current is the current of magma that moves the tectonic plates in directions.
As the magma on the bottom is heated by the core it gets hotter and less dense so it floats to the top and gets pushed by the hotter magma coming in and cycles around in a current which the plates move on

Question 22

where are earthquakes and volcanoes most prominent

Answer 22

where the tectonic plates (continents) meet and rub/push on each other which can cause earthquakes or go under each other and let magma come up making volcanoes next to the borders