Please enable JavaScript.
Coggle requires JavaScript to display documents.
What are we learned - Coggle Diagram
What are we learned
What Are Waves?
Waves transfer energy from one place to another without transferring matter overall. They can travel through different materials or through empty space. Waves are found everywhere around us, including sound, light, water, and electromagnetic waves.
Waves have different parts and properties. These include wavelength, frequency, amplitude, and speed. Each property helps us understand how a wave moves and behaves.
There are two main types of waves: transverse and longitudinal. They are different because the particles move in different directions when the wave travels.
Transverse Waves
Light is a transverse wave. Light can travel through empty space, so it does not need air or another material to move from one place to another.
Transverse waves have crests and troughs. A crest is the highest part of the wave, while a trough is the lowest part of the wave.
In transverse waves, particles move up and down while the wave moves forward. The particles move at a right angle to the direction the wave travels.
Visible Light
Visible light is the part of the electromagnetic spectrum that our eyes can see. It allows us to see objects, people, colours, and places around us.
Visible light has different colours, including red, orange, yellow, green, blue, and violet. Each colour has a different wavelength and frequency.
Visible light is a transverse wave. It can travel through empty space, which allows sunlight to travel from the Sun to Earth.
Electromagnetic Spectrum
The electromagnetic spectrum is a range of different electromagnetic waves. It includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.
Radio waves have the longest wavelengths and lowest frequencies. Gamma rays have the shortest wavelengths and highest frequencies.
As wavelength becomes shorter, frequency becomes higher. Energy also generally increases. Gamma rays have much more energy than radio waves.
Longitudinal Waves
In longitudinal waves, particles move back and forth in the same direction as the wave. The particles move parallel to the direction that the wave travels.
Longitudinal waves have compressions and rarefactions. Compressions are where particles are close together. Rarefactions are where particles are spread farther apart.
Sound is a longitudinal wave. Sound needs a material, such as air, water, or a solid, to travel from one place to another.
Wavelength
Wavelength is the distance between two matching points on a wave. For example, it can be measured from one crest to the next crest.
Wavelength is measured in metres, using the symbol m. A short wavelength has waves close together, while a long wavelength has waves farther apart.
Wavelength is connected to frequency. When wave speed stays the same, a higher frequency means a shorter wavelength, while a lower frequency means a longer wavelength.
Colour and Wavelength
Different colours have different wavelengths. Red light has the longest wavelength in visible light, while violet light has the shortest wavelength.
Red light has a lower frequency because it has a longer wavelength. Violet light has a higher frequency because it has a shorter wavelength.
When wavelength gets shorter, frequency gets higher. The colour changes from red toward violet as the wavelength becomes shorter.
Eyes-How We See
Light reflects off objects and enters the eye through the pupil. The lens focuses the light onto the retina at the back of the eye.
The retina detects light and colours using special cells. It changes the light into electrical signals that can be sent to the brain.
The optic nerve carries signals from the retina to the brain. The brain processes them, allowing us to see colours, shapes, objects, and movement.
Amplitude
Amplitude is the distance from the middle resting position to the top or bottom of a wave. It shows how big the wave is.
A bigger amplitude means the wave usually carries more energy. A smaller amplitude means the wave usually carries less energy.
For sound, amplitude affects how loud the sound is. A bigger amplitude usually makes a louder sound, while a smaller amplitude makes a quieter sound.
Wave Speed
Wave speed tells us how fast a wave moves from one place to another. It shows how much distance a wave travels in a certain amount of time.
Wave speed is measured in metres per second, written as m/s. Different waves can travel at different speeds depending on their type and medium.
The formula for wave speed is speed = frequency × wavelength. We can use this formula to calculate how fast a wave travels when we know its frequency and wavelength.
Frequency and wavelength have an opposite relationship when wave speed stays the same. If frequency increases, wavelength becomes shorter. If frequency decreases, wavelength becomes longer.
High-frequency waves have many waves passing a point every second. Because the speed stays the same, these waves have shorter wavelengths.
Low-frequency waves have fewer waves passing a point every second. Because the speed stays the same, these waves have longer wavelengths.
Frequency
Frequency tells us how many complete waves pass a point every second. It shows how often a wave repeats its movement.
Higher frequency means more waves pass each second. Lower frequency means fewer waves pass each second. Frequency and wavelength have an opposite relationship when speed stays the same.
Ear-How We Hear
Sound waves enter the ear through the ear canal and make the eardrum vibrate. The vibrations then move through the middle ear.
Three tiny bones pass the vibrations into the inner ear. They help make the vibrations stronger before they reach the cochlea.
The cochlea changes vibrations into electrical signals. The auditory nerve carries these signals to the brain, allowing us to recognise and understand different sounds.
Frequency is measured in hertz, written as Hz. For example, 5 Hz means five complete waves pass a point every second.
-