Waves

Prism

A clear object that bends white light to separate it into the colors of the rainbow.

What is the relationship between the amplitude of a wave and the amount of energy it produces?

Higher amplitude waves transfer more energy. High amplitude light waves produce bright, visible colors, whereas high amplitude sound waves produce loud sounds.

Frequency

How many waves pass a point in 1 second.

Energy

It makes things happen! (Or more formally: the ability to do work)

How is a sound wave different from a light wave?

Sound waves needs to travel through matter, but light does not need to travel through matter.

What are some sources of electromagnetic radiation that you have encountered in your daily life in the past week?

Students might have encountered radio waves (radio, TV, internet, cell phones), microwaves (microwave oven), infrared waves (heat from any object), visible light (sunlight and artificial lights), ultraviolet light (the Sun), possibly X-rays (medical imaging). Some students may have even encountered gamma rays (radiotherapy).

Energy

The ability to cause changes in matter.

Trough

The bottom of a wave.

How do you measure the amount of energy something has?

The faster a given object is moving, the more energy it has. This happens with all matter and can be measured in many different ways in the form of heat or electrical current.

Amplitude

The height of a wave from its resting point.

Amplitude

The height of a wave. Usually measured from the wave's resting point to the peak of the wave.

Amplitude

The height of the wave from its resting point.

Wave Peak

The highest point on a wave. Also called the crest.

Wavelength

The length of one wave measured from peak to peak.

Why do some electromagnetic waves have more energy than others?

The main pattern observed in the electromagnetic spectrum is that waves with shorter wavelengths and higher frequencies have higher energy. For a wave of a given wavelength, amplitude is also related to energy. So a visible light wave with a higher amplitude would have greater energy and be observed to have a higher intensity.

Frequency

The number of waves that pass a point in one second.

Electromagnetic spectrum

The range of waves that includes radio waves, microwaves, infrared waves, visible light, ultraviolet light, X-rays, and gamma rays.

Particle

The smallest possible unit of matter.

Absorption

The transfer of the energy of the wave to the medium it comes into contact with.

What kinds of patterns can be observed for transverse waves?

Transverse waves are a repeating pattern of peaks and troughs. This pattern remains the same although changes to the energy cause the peaks and troughs to get closer together or further apart (wavelength) or the peaks and troughs to be higher or lower (amplitude).

What causes waves?

Vibrations in matter cause waves. (Students are likely to be familiar with vibrations causing sound waves and with disturbances in water causing water waves. They are not likely to know that the movement of charged particles causes electromagnetic waves.)

Sound Waves

Vibrations of air particles that transmit sound. Sound waves are a type of longitudinal wave.

How do we use or encounter electromagnetic waves in everyday life?

Vision (visible light), communications/entertainment (radio waves), medical imaging (X-rays), cooking food (microwaves), heating (infrared), and sunlight (ultraviolet) are examples of waves we encounter in our everyday life.

What are some examples of waves in everyday life?

Water waves, sound waves, light waves, and waves in a string or slinky are examples of waves in everyday life.

What is wavelength?

Wavelength is the distance from the peak of one wave to the peak of the next wave.

What are waves?

Waves are regular patterns of motion that transfer energy from place to place without transferring matter. Waves exhibit repeating patterns.

Do waves move matter as they travel?

Waves can cause matter to move back and forth in place, but waves do not transport matter. Examples include sound causing matter to vibrate as the sound waves travel through a material, a boat rising and falling in the open ocean as waves pass beneath the boat, or a "wave" travelling around a stadium as fans stand up and sit down without moving away from their seats.

Reflection

Waves hitting matter and bouncing off.

Do waves transfer matter?

Waves transfer energy, not matter.

What is amplitude?

When talking about waves, amplitude is the height of the wave (above its resting point). How tall or short a wave is.

Longitudinal Wave

When the disturbance moves parallel to the direction of the wave. Put simply: When a wave moves forward and back.

Transverse Wave

When the disturbance moves perpendicular to the direction of the wave. Put simply: When a wave moves up and down.

Wave

A repeating pattern of motion that transfers energy from place to place.

Wave

A repeating pattern that can transfer energy from place to place.

Wavelength

The distance from one peak of a wave to its next peak.

What properties do all waves have?

All waves have amplitude, wavelength, and frequency.

What makes one wave different from another?

Aside from the type of wave (mechanical vs. electromagnetic), one wave can be distinguished from another by its measurable properties: energy, wavelength, frequency, and amplitude.

What are some examples where using electromagnetic radiation other than visible light to view an object can show us more about that object?

Astronomers use radio waves, microwaves, and infrared waves to view objects in space. Radiologists use X-rays to see inside the body. Thermal imaging cameras show areas of hot and cold. Firefighters can use such cameras to find people inside a smoke-filled room. Bees use ultraviolet waves to help them see patterns on flowers that do not appear to the human eye.

Hertz

The unit of measurement for how many waves pass a point in 1 second.

Why does the salt vibrate on the speaker when the music is turned on?

When the music is turned on sound waves cause the salt to vibrate just like sound waves cause air particles to vibrate.

Electromagnetic radiation

A type of wave that transfers energy.

Nanometer

A unit of measurement 1 million times smaller than a millimeter.

What is a wave?

A wave has a repeating pattern with a specific wavelength, frequency, and amplitude.

How does increasing energy affect the amplitude of a wave?

Adding energy to a transverse wave causes the wave to become taller (amplitude increases).

How does increasing energy affect the wavelength of a wave?

Adding energy to a wave causes the wavelength to become shorter, meaning the waves are closer together (wavelength decreases).

Name some different types of electromagnetic waves. What do they all have in common? How are they different?

Electromagnetic waves include radio waves, microwaves, infrared waves, visible light, ultraviolet light, X-rays, and gamma rays. All electromagnetic waves transfer energy. They all travel the same speed (i.e., the "speed of light"). The different waves along the spectrum differ in their wavelength, frequency, and energy. As you move from radio to gamma waves, wavelength decreases, frequency increases, and energy increases.

How does energy move from one place to another?

Energy can be moved from one place to another by moving objects or through sound, light, or electrical currents. When objects collide, energy is transferred from one object to another, thereby changing its motion.

Where do you find energy?

Energy is present anywhere there are moving objects, sound, light, or heat.

Transmittance

Energy of the wave passes through the medium.

What happens when light is shined on an object?

Light can be absorbed, reflected, or transmitted through an object, depending on the object's materials and the wavelength of light.

How does the amplitude of waves help us understand light?

Light waves are measured in nanometers. Higher amplitude light waves will be brighter and show colors such as red, whereas light waves with lower amplitude (and higher frequency) show colors such as violet.

How does a light wave travel?

Light waves travel in straight lines. But when they hit an object, they bend in different directions and will travel in straight lines in a different direction.

What kinds of patterns can be observed for longitudinal waves?

Longitudinal waves are a repeating pattern of compression and expansion. This pattern remains the same although changes to the energy causes the compressed areas to become closer together or further apart (wavelength).

Which color of visible light would have the least energy? Which would have the most energy? How do you know?

Red light has the longest wavelength and therefore the lowest energy of the visible light spectrum. Note that the prefix infra means below, so infrared radiation is just below red light on the electromagnetic spectrum. Violet has the shortest wavelength and therefore the highest energy of the visible light spectrum. Note that the prefix ultra means beyond, so ultraviolet radiation is just above violet light on the electromagnetic spectrum.

How does sound move from one place to another? Explain and/or draw a picture.

Sound is not visible, but it travels as a longitudinal wave that causes air particles to vibrate. The particles vibrate in the form of a wave as the sound travels through the air.

Give two examples of how sound waves interact with matter.

Sound waves can be transmitted through objects, like when you hear music from another room. Sound waves can also reflect off of objects, like when you hear an echo across cliffs.

Wavelength

The distance between wave peaks. Usually measured from the peak of one wave to the peak of the wave next to it.

Why can't sound be heard when the phone playing music is placed inside the vacuum jar? Explain what you think is happening.

When the phone playing music is placed inside the vacuum jar and the vacuum is turned on, all of the air is removed from the jar. Since there are no air particles for the sound waves to travel through, the sound cannot be heard even though the music is still playing.

How can you describe the differences between waves?

You describe a wave by observing its properties. All waves have amplitude, wavelength, and frequency, but waves can be different from one another. For example, waves with higher amplitude will be louder (sound) and brighter (light) than waves with lower amplitude and wavelength.

Microwaves are very efficient at heating water

but all electromagnetic waves can cause matter to heat up. Why is this?, All electromagnetic waves transfer energy. When this energy is absorbed by matter, it is converted into heat because it causes the particles in the matter to vibrate more rapidly.

How do the terms light

radiation, and waves relate to one another?, Radiation refers to electromagnetic waves, which are one specific type of wave. Light refers to the portion of the electromagnetic spectrum that is in or near the visible light spectrum. So light is both a wave and a type of radiation.

When Zoe and Izzy demonstrated waves using the slinky

which type of wave did they observe?, Zoe and Izzy use the spring to demonstrate both transverse and longitudinal waves. Water waves are transverse waves and sound waves are longitudinal waves.