Basic Physics about waves

   velocity/frequency= wavelength

Velocity of wave= wavelength x frequency

Frequency= number of times/speedf = 1/T where, f is the frequency in hertz, and T is the time to complete one cycle in seconds. The frequency formula in terms of wavelength and wave speed is given as, f = 𝜈/λ where, 𝜈 is the wave speed, and λ is the wavelength of the wave.

Meters- amplitude

Lambda- represents wavelength

Meters: Wavelength

m/s- velocity

Frequency: Hertz (hz)

Types of waves: 

Transverse waves: Movements of particles in these waves move perpendicular to the motion of the energy. 

Longitudinal waves Movements of waves are parallel to the motion of the energy. 

Surface waves: The particles in these waves move in a circular motion. 

Examples: 

• Sound waves are longitudinal waves. 

• Movements through solid objects such as stretched rope are transverse waves. 

• Ocean waves are surface waves. 

    Anatomy of a Wave

Wavelength: Measured from crest to rest for from through to through

Amplitude: Measured from the top of the resting line to the crest or the through. 

Frequency and wavelength: Have an inversely proportional relationship. 

Frequency units: hertz (Hz)

Wavelength units: meters (m)

Properties of waves:

They all have a frequency

They all have a pattern

They all have amplitude

They all have a wavelength 

amplitude, wavelength, frequency, and speed.

 Energy: Anything that can get an object to do work (an object's ability to make something move or change)

Timbre: the distinctiveness of a sound (think quality and tone.)

Warm-up questions

What two things do sound waves need in order to travel: A medium and a source

Does sound move faster through solids or gasses: Solids, as the particles in solids, are less far apart, and so they are more likely to hit each other and the sound waves. 

What’s a medium and what does it have to do with sound? Why can’t sound waves travel in space: A medium is something that waves travel through. Sound waves can’t travel in space because there is no medium in space. 

What’s the relationship between sound, amplitude, and wavelength: Amplitude influences the volume of a wave, and the higher the volume the louder the sounds. Wavelength influences pitch, and pitch, and wavelength have an inversely proportional relationship. 

Light can cause objects to heat up, as light waves carry energy, and objects absorb energy. 

Wavelength determines where a light is on the Electromagnetic Spectrum. 

Amplitude and brightness have a directly proportional relationship. 

Mechanical wave: waves that transfer energy through matter

Electromagnetic wave: A wave that can travel through a vacuum (empty space) 

Wave: A disturbance that transfers energy from one place to another. 

Volume: 

Describe how loud the sound is. 

Determined by amplitude 

Quiter

Pitch

Describe how high or low sound is. 

Determined by waves frequency 

Key Concepts: 

When a material absorbs energy from light, the energy causes the material to change. 

Different types of light have different wavelengths. 

Different light colors have different wavelengths and frequencies. 

Key terms:

Transmit: To pass-through

Reflect: To bounce off without absorbing

Vocabulary: 

Define these terms in your own words, and give examples/diagrams when relevant:

• Wave: A disturbance that transfers energy from one place to another.

• Energy: An object's ability to do work (work being something that  causes something to move or change.)  

• Medium: Something that carries a wave. 

• Mechanical Wave: Waves that transfer energy through matter 

• Electromagnetic Wave: Waves that can travel through a vacuum. 

• Longitudinal Wave: Movements of these waves are parallel to the motion of the energy. 

• Transverse Wave: Movements of particles in these waves are perpendicular to the motion of the energy. 

• Amplitude (+units): The height of a wave.

• Wavelength (+units): The distance between crest to crest or trough to trough. (meters) (m)

• Frequency (+units) Measures how many times a wave occurs. (Units hertz) (hz)

• Crest: The highest point on a wave.

• Trough: The lowest point on a transverse wave.

• Pitch: The perception of frequency, in other words how high or low a sound is. 

• Natural/resonant frequency: A resonant frequency is a natural frequency of vibration determined by the physical parameters of the vibrating object. For example, if a wave matches an object's resonance frequency, the object will vibrate and likely break. 

• Electromagnetic spectrum: the range of all types of EM radiation

• Refraction: The bending of light as it passes from one transparent substance into another.

• Calculations:

 Show all work, including formula and correct units.

1. A sound wave traveling through a solid material has a frequency of 500 hertz: The wavelength of the sound wave is 2 meters. What is the speed of sound in the material?

3. What is the speed of a wave with a frequency of 15 Hz and a wavelength of 29 m?

4. A sound wave in a steel rail has a frequency of 620 Hz and a wavelength of 10.5 m. What is the speed of sound in steel?

5. What is the wavelength of a sound wave with a frequency of 50 Hz? (Speed of sound is 342 m/s)

Concept Questions:

1. What properties do all waves share? What are some major differences between some types of waves? All waves have an amplitude, frequency, wavelength and pattern. Some waves need mediums to travel, such as mechanical waves, but electromagnetic waves don’t need mediums to travel. Some waves are parallel, others are perpendicular or circular. 

2. What is the relationship between a wave’s frequency and its wavelength? That relationship is inversely proportional. As a wave’s frequency increases, it’s wavelength decreases, and when a wave’s frequency decreases, it’s wavelength increases. 

3. How do sound waves move? What do they need in order to move? What affects their speed? A sound wave is a disturbance that travels through a medium. Sound waves are vibrations. Sound waves travel fastest through solids and hot air. They travel faster through solids because the particles in solids are less far arpt, and so they are more likely to hit eachother. Molecules at higher temperatures have more energy and can vibrate faster and allow sound waves to travel more quickly. 

4. How does changing a sound wave’s amplitude affect what we hear? What about its frequency? The larger the amplitude of a sound wave is, the louder the sound is. The smaller the amplitude is, the quiter the sound is. The higher the frequency is, the higher the sound is. The lower the frequency is, the lower the sound is. 

5. How is it possible to shatter a glass using only your voice?  If the glass is tubular and has some small cracks in it, it is possible to shatter glass using your voice only. This is possible if your voice is loud enough, and if the sound wave matches the glass’s resonance, then the glass should vibrate, and eventually break. 

6. How does changing a light wave’s amplitude affect what we see? What about its frequency? As light waves amplitude increases, the intensity of the light increasers, and so you see a brighter light. As a light waves amplitude decreases, the intensity of the light decreases, so the light will become dimmer. 

7. What are the three ways that light can interact with a material?: It can reflect, absorb, or transmit light. 

8. How do our eyes perceive color?: The cones in your eyes help your brain interpret what color you see. (The color cones absorb reflected light.) 

9. What is refraction? When does it happen? Give an example. When light bends as it passes from one transparent medium to another. When light bends as it hits a prism, or when rainbows form, refraction is occurring.