Science: waves and information Flashcards
True or false: sound and light are types of waves
True
True or false: ripples in water are not waves
False
What causes waves?
Vibrations or disturbances. For example, tremors from earthquakes will cause waves in nearby waters.
Where do waves get their energy?
The energy that causes vibrations, which causes waves, are carried in the waves
Do waves need a medium (material) to travel?
Yes and no.
Light and radio waves can travel through empty space, while sound waves need a medium (material) such as air or water.
Which type of wave is faster, light or sound?
Light waves are faster.
What are the 3 key characteristics of waves?
Wavelength, amplitude and frequency
Draw a wave and label its amplitude, wavelength, crest and trough
Show dad
True or false: high frequency waves have a lower sound than low frequency waves
False.
High frequency waves have a higher sound.
What happens to wavelength when waves increase in frequency?
As frequency increases, wavelength decreases and become shorter
Why do ripples get smaller and smaller?
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.
Why is a tsunami dangerous as it reaches land?
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.
What happens in superposition, when 2 waves meet?
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.
What is a spectrum?
It’s the light that bounces off an object
Draw illustrations of what happens when light meets different types of matter below:
- Reflection
- Refraction
- Absorption
- Transmission
- Diffraction
- Scattering
Show dad
What happens when light passes through a prism?
It bends and the light spreads out into all the colors of the light spectrum
Why do colors of a rainbow always appear in the same order?
Because the colors are arranged by the order of their wavelength, which never changes
True or false: in order for us to see an object, there needs to be light that bounces off of it
True.
What do the lens, pupil and retina do?
Draw an eye and label the lens, pupil, retina and optic nerve
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.
How do our eyes see color?
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
What are some examples of waves that we cannot see?
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
Why can’t see anything in the dark?
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.
What are the 3 key components of sound waves? Describe each.
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.
How are radio waves used in our modern society?
Radio waves are used to send signals with messages by radios, TVs, mobile phones and satellites
Today, messages can be sent by radio waves over long distances in a matter of seconds. Why is this important?
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.
What are the 3 key parts of devices that send and receive radio waves? Describe each part.
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.
What are the advantages of digital signals over analog signals?
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.
Fill in the blanks:
Sound is a ____________ (longitudinal / transverse) wave.
Light is a ____________ (longitudinal / transverse) wave.
Sound is a longitudinal wave.
Light is a transverse wave.
True or false: sound can travel through liquids and gasses, but not solids.
False.
Sound can travel through all 3.
Fill in the blank
The energy of a sound wave depends on its ____________ (frequency / amplitude).
Amplitude
What happens when a sound wave hits an object which is already vibrating at a frequency that matches the sound wave?
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.
What is the relationship between frequency and the number of crests/troughs?
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.
