Science: waves and information

Question 1

True or false: sound and light are types of waves

Answer 1

True

Question 2

True or false: ripples in water are not waves

Answer 2

False

Question 3

What causes waves?

Answer 3

Vibrations or disturbances. For example, tremors from earthquakes will cause waves in nearby waters.

Question 4

Where do waves get their energy?

Answer 4

The energy that causes vibrations, which causes waves, are carried in the waves

Question 5

Do waves need a medium (material) to travel?

Answer 5

Yes and no.

Light and radio waves can travel through empty space, while sound waves need a medium (material) such as air or water.

Question 6

Which type of wave is faster, light or sound?

Answer 6

Light waves are faster.

Question 7

What are the 3 key characteristics of waves?

Answer 7

Wavelength, amplitude and frequency

Question 8

Draw a wave and label its amplitude, wavelength, crest and trough

Answer 8

Show dad

Question 9

True or false: high frequency waves have a lower sound than low frequency waves

Answer 9

False.

High frequency waves have a higher sound.

Question 10

What happens to wavelength when waves increase in frequency?

Answer 10

As frequency increases, wavelength decreases and become shorter

Question 11

Why do ripples get smaller and smaller?

Answer 11

A wave carries and transfers energy from the vibration that caused it, so ripples carry and transfer the energy that caused the ripples. But as a wave travels and spreads out, its energy also spreads out over larger areas, that’s why the ripples get smaller and smaller as it spreads out.

Question 12

Why is a tsunami dangerous as it reaches land?

Answer 12

A wave carries and transfers energy from what caused it. Tsunamis are caused by earthquakes at the bottom of the ocean floor, so it carries that energy. As it reaches land, it will transfer that earthquake energy to land, which could cause massive destruction.

Question 13

What happens in superposition, when 2 waves meet?

Answer 13

When the 2 crests meet, their amplitudes match up and the wave is taller for a moment.

But when the crest of one wave meets the trough of the other wave, they cancel each other out and the wave becomes still for a moment.

Question 14

What is a spectrum?

Answer 14

It’s the light that bounces off an object

Question 15

Draw illustrations of what happens when light meets different types of matter below:

• Reflection
• Refraction
• Absorption
• Transmission
• Diffraction
• Scattering

Answer 15

Show dad

Question 16

What happens when light passes through a prism?

Answer 16

It bends and the light spreads out into all the colors of the light spectrum

Question 17

Why do colors of a rainbow always appear in the same order?

Answer 17

Because the colors are arranged by the order of their wavelength, which never changes

Question 18

True or false: in order for us to see an object, there needs to be light that bounces off of it

Answer 18

True.

Question 19

What do the lens, pupil and retina do?

Draw an eye and label the lens, pupil, retina and optic nerve

Answer 19

The lens lets in light into the eye.

The pupil bends and focuses the light to the retina.

The retina has receptor cells that are sensitive to different colors, and they send messages to the brain about the light it receives from the lens, to be decoded by the brain.

Show dad the drawing.

Question 20

How do our eyes see color?

Answer 20

First, there mist be light that bounces off of an object. The object might reflect some of the colors of the light’s spectrum, or absorb all of it. The colors that are not absorbed are then reflected to our eyes. When all the colors are absorbed, then all we see is black color.

For example, when we see green leaves, there must be light that bounces off of the leaves. The leaves absorb all the colors of the spectrum except green, which reflects to our eyes

Question 21

What are some examples of waves that we cannot see?

Answer 21

Waves that we can see is called the visible spectrum. We can only see a small part of the electromagnetic spectrum.

Examples of waves we cannot see are:
- Xrays
- Radio waves
- Microwave

Question 22

Why can’t see anything in the dark?

Answer 22

We need light to bounce off an object in order to see it. There is no light in the dark and that’s why we can’t see anything.

Question 23

What are the 3 key components of sound waves? Describe each.

Answer 23

1) Pitch: this is the frequency of sound. High and low pitches make high and low sounds.

2) Volume: this is the amplitude of sound. High and low volumes make loud and low sounds.

3) Resonance: when sound waves reflect back into each other, they can combine and make sound louder.

Question 24

How are radio waves used in our modern society?

Answer 24

Radio waves are used to send signals with messages by radios, TVs, mobile phones and satellites

Question 25

Today, messages can be sent by radio waves over long distances in a matter of seconds. Why is this important?

Answer 25

Compared to the past when people sent messages by smoke signals, delivered by horses, or by trains or airplanes, modern communication is faster, more efficient and more accessible to everyone. This makes it easier and more convenient to communicate with others.

Question 26

What are the 3 key parts of devices that send and receive radio waves? Describe each part.

Answer 26

1) Transmitters send out radio signals.

2) Antennae receives radio signals.

3) Receivers convert the received radio signals into useable messages such as text, images or data.

Question 27

What are the advantages of digital signals over analog signals?

Answer 27

Digital signals are easier to encode into radio waves to be sent over long distances. Today, we convert information into digital numbers, which is easier to transmit than analog signals which are a continuous and full stream of information which is not encoded.

Digital signals play an important role in how computers connect to and communicate through the Internet.

Question 28

Fill in the blanks:

Sound is a ____________ (longitudinal / transverse) wave.

Light is a ____________ (longitudinal / transverse) wave.

Answer 28

Sound is a longitudinal wave.

Light is a transverse wave.

Question 29

True or false: sound can travel through liquids and gasses, but not solids.

Answer 29

False.

Sound can travel through all 3.

Question 30

Fill in the blank

The energy of a sound wave depends on its ____________ (frequency / amplitude).

Answer 30

Amplitude

Question 31

What happens when a sound wave hits an object which is already vibrating at a frequency that matches the sound wave?

Answer 31

The sound will get louder. This is called resonance. It happens often in music, when different instruments play notes at the same frequency and the sound of the orchestra or band gets louder.

Question 32

What is the relationship between frequency and the number of crests/troughs?

Answer 32

The higher the frequency, the higher number of crests/troughs.

This is because frequency is the measured by the number of crests that pass a fixed point over a certain period of time. As frequency increases, more crests will pass the measuring point in the same period of time.