Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Science Y9 > Chapter 6 > Flashcards

Chapter 6 Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What is the loudness of a sound used for

A

to describe how quiet or loud a sound appears

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the 2 variables loudness depends on

A
  1. How much the object is vibrating
    -the greater the distance of each vibration,the louder the sound

2.How far away the vibrating object is
-the further away the quieter the sound we hear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a waveform

A

Graph that shows the distance that the particles in a sound wave move forward and backward in time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is an amplitude

A

the maximum distance that particles move, either forward or backward in a sound wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

In what 2 ways can amplitude be measured?

A

1.Distance from zero to the peak of the graph
2. Distance from zero to bottom (trough) of the graph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is peak in terms of amplitude

A

the highest point of the waveform graph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is trough in terms of amplitude

A

the lowest point of waveform graph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the function of an oscilloscope? and How

A

Oscilloscope displays waveforms of soundwaves. It uses a microphone to detect the sound and then produces a waveform of sound on a screen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the number of vibration in each second called

A

frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What makes the pitch of the sound increase

A

As the frequency of a sound wave increases, the pitch of the sound also increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the unit of frequency?

A

hertz or Hz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

In an oscilloscope, what is the loudness of the sound measured by?

A

Amplitude (the distance that the particles move forward and backward)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

In an oscilloscope, what is the frequency of the sound measured by?

A

The number of vibrations in a second

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Does vibrating objects that are shorter or longer make higher pitch sounds

A

Vibrating objects that are shorter.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a useful analogy for soundwaves?

A

Water waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is interference

A

an effect that is produced when the waves meet each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what do soundwaves produce when they meet each other

A

interference

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is a requirement for interference to happen

A

Only happens when the waves are of the same type

19
Q

What makes Interference easiest to detech

A

when the waves have the same frequency and the same amplitude

20
Q

What are the 2 effects that interference can produce?

A

1.Waves can reinforce each other
2.Waves can cancel each other

21
Q

What does the word reinforce means in terms of sound waves

A

It means to make it stronger

22
Q

When will waves reinforce?

A

When they meet with the PEAKS TOGETHER and with the TROUGHS TOGETHER

Two waves can interfere to reinforce when the wave peaks arrive together

23
Q

When sound waves interfere to reinforce, what happens?

A

The amplitudes of the two waves that interfere are added together but the frequency of the two waves that interfere does not change

The sound becomes louder

24
Q

When will waves cancel?

A

when they meet with the PEAKS AND TROUGHS together.

25
Q

What does the word CANCEL mean in terms of soundwaves.

A

adding together to make zero

26
Q

What causes the waves to cancel?

A

When the peaks of one’s wave meet the troughs of another wave that has the same amplitude.

27
Q

What are the requirements for two sound waves to cancel completely?

A

Their frequencies must be the same
Their amplitudes must be the same.

28
Q

How do noise-cancelling headphones work?

A

The headphones pick up the sounds using a small microphone from the surrounding.

After analysing the sounds, the headphone will create another sound wave with the same amplitude and frequency.

This new sound wave is used to cancel the sound wave from the surroundings.

29
Q

If two speakers at a concert release soundwaves, why won’t it cancel?

A

The soundwaves will be reflected off objects. It would add many more waves to the pattern in the diagram.

30
Q

What is the collision theory also called?

A

The giant impact hypthesis

31
Q

Explain the collision theory

A

A newly formed planet(Theia), about the same size as Mars, collided with the newly formed Earth.

The collision caused rocks and dust to break away from both planets.

The theory states that Earth was formed from the two planets joined together.

The moon was formed when the rocks and dust was pulled together by gravity

32
Q

What are evidence that supports the collision theory?

A

-Moon is less dense than the Earth

-Samples of rock from the Moon show that its surface was once molten

-The Moon has a small iron core, similar to the Earth

-The collision theory fits the theory of how the Solar System was formed

-The composition of rocks on the Earth and Moon are the same

33
Q

What are evidences that contradicts the collision theory

A

-The surface of the Earth does not appear to ever have been molten. A collision that formed the Moon would have caused th surface of the Earth to melt

  • Venus has no moon.Collisions in the early years of the Solar System would have been common and Venus was expected to have a moon formed in the same way

-The composition of rocks on the Moon would be expected to be more similiar to rocks on Theia than rocks on Earth. But in fact the composition of the moon is more similar to Earth.

34
Q

What are Nebulae

A

Nebulae are clouds of dust and gas in space

35
Q

What is the singular noun of Nebulae

A

Nebula

36
Q

What are the gases found in nebulae most formed from

A

hydrogen and a smaller quantity of helium

37
Q

What is a stellar nursery

A

stellar nursery is an area in space where stars are formed.

38
Q

What occurs in a stellar nursery?

A

The dust and gas can start to collapse together under the force of gravity.

When the mass of dust and gas collects together and becomes larger, the force of gravity pulling inward increases.

When the force gets very large, the pressure inside the new star also gets very large

The high pressure causes heat and the heat can cause atoms to react with each other. This causes the new start to give out heat and light.

39
Q

from where the mantle of the Earth is heated from

A

The inner core

40
Q

How does convection current occur in the mantle.

A

The inner part of the mantle gets thermal energy from the core

The fluid expands when heated and becomes less dense that the fluid surrounding it.

This hotter,less dense fluid in the mantle rises towards the crust, cools and sinks again.

41
Q

How does the fossil record provide evidence for tectonic plates

A

fossils of extinct creatures have been found in parts of countries that would fit together in the jigsaw model of the continents.

This gives more evidence for the hypothesis that these continents were once joined

41
Q

How does the continental jigsaw appearance serve as an evidence for the tectonic plates

A

A hypothesis that states that there was once only one large continent that eventually separated.

The separate parts became some of the tectonic plates. The convection currents from the mantle drove their movements

42
Q

How does the alignment of magnetic materials in rocks serve as evidence for tectonic plates

A

Magnetic crystals in molten rocks line up to point north in the same way as compass needle

Scientists use these crystals to tell the direction of the Earth’s magnetic field at the time when rock became solid

rocks from middle of the Earth’s oceans revealed that magma is coming up from the mantle and solidifying to form new rocks

This action pushes the continents away from each other.

Science Y9 (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions