# Waves: The motion that occurs when energy moves through matter

## Presentation on theme: "Waves: The motion that occurs when energy moves through matter"— Presentation transcript:

Waves: The motion that occurs when energy moves through matter
(liquids, solids, and gases)

Lesson 1: Ocean Waves: The motion in the ocean

Q: What do you think is the main cause of an ocean wave?
The Moon Large Whales The Wind Pirates

A: (B) The Wind! Ocean waves are mostly caused by wind.
Wind is the energy that travels through the water (matter) making a wave motion. However, waves are not always caused by wind. Waves can be caused by any type of energy or force. Tsunamis (storms in the ocean in which huge waves occur) are caused by earth quake waves and shifting of the land at the bottom of the ocean.

True or False: Water is not really traveling when a wave occurs.

A: True! Water basically stays right where it is when a wave occurs.
The wave movement is actually the energy passing through the water. It’s kind of like if you tied a rope to a tree, and then moved your arm up and down holding the other end of it. The rope wouldn’t go any where; it just makes a wave motion as the energy from your arm passes through it.

Transverse Longitudinal
Q: There are two different kinds of waves: transverse waves and longitudinal waves. What kind of waves do you think ocean waves are? Transverse Longitudinal

Transverse wave motions occur in right angles and move up and down.
A: (A) Transverse! Transverse wave motions occur in right angles and move up and down.

True or False: It’s impossible to measure a wave.

A: False! Waves can be measured in many different ways:
Wave Amplitude: the height from the still water line to the top of the wave (its crest) or from the still water line to the bottom of the wave (its trough.) Wave Length: the distance from crest to crest or from trough to trough. Wave Frequency: how fast the wave travels through water, or how many waves pass a given location per second.

True or False: Ripples in any water are also considered waves.

A: (A) True! Ripples are still just energy moving through water (matter) creating a smaller wave motion. Waves can occur in any kind of water: Rivers Ponds Lakes Swimming Pools Puddles Even Your Bathtub!

Let’s Recap: Waves are energy traveling through matter.
Ocean waves get their energy mostly from the wind. Energy is traveling through the water, the water itself is not actually going any where! Ocean waves are transverse waves – waves that occur in the pattern of a right angle and move up and down. Ocean waves can be measured by their amplitude, wave length, and frequency.

The Motion in the Ocean https://www.youtube.com/watch?v=HX9gxnypVJ4

The stronger the wind, the bigger the wave. For this reason, surfers often watch the weather closely to see when a hurricane or strong weather is coming so they’ll have big waves to surf on. The biggest wave ever seen was in 1933 in the North Pacific. It was 112 feet tall – that’s the height of a seven story building! If a surfer hit a wave hard, it isn’t soft like some people may imagine. It can actually feel like hitting concrete.

Lesson 2: Sound Waves

Q: Do sound waves and ocean waves have anything in common?
No. Other than the fact that they’re both called waves, they have nothing else in common. Yes. They’re both forms of energy moving through matter. Yes. They are actually both made of water.

A: (B) Yes. They’re both forms of energy traveling through matter.
Sound is caused by vibrations. A force causes molecules to vibrate. The vibration is the energy that travels through the matter (usually air) in the form of a sound wave.

Q: Do you think sound waves are transverse or longitudinal waves?

A: (B) Longitudinal! Longitudinal Waves travel in one direction without moving up and down in right angles (which is what transverse waves do.)

True or False: Sound waves only travel through air.

A: False Sound can travel through all matter (solids, liquids, and gases).
Sound traveling through matter from fastest to slowest: 1.Solids 2.Liquids 3.Gases

Q: What causes sound waves to make different noises?
The amount of force causing the vibration The amount of matter the sound wave is traveling through The type of matter that the sound wave is traveling through The length of the initial force All of the above

A: (E) All of the above! Sound waves make different noises based on:
The amount of force causing the vibration The amount of matter the sound wave is traveling through The type of matter that the sound wave is traveling through The length of the initial force

Let’s Recap: Just like ocean waves, sound waves are also energy traveling through matter (vibrations – usually through air.) Sound waves are longitudinal waves (They travel in one direction without moving up in down.) Sound waves can travel through all types of matter. The force causing the vibration, the length of the force causing the vibration, the amount of matter the wave is traveling through, and the type of matter the wave is traveling through determines the way we hear the sound wave.

Dogs can hear sound at a higher frequency than humans, allowing them to hear noises that we can’t. Sound is used by many animals to detect danger, warning them of possible attacks before they happen. Sound can’t travel through a vacuum (an area empty of matter). The speed of sound is around 767 miles per hour. The loud noise you create by cracking a whip occurs because the tip is moving so fast it breaks the speed of sound!

Lesson 3: Light Waves and Color (And Other Waves on the Electromagnetic Spectrum)

Q: Do you think that light waves are transverse or longitudinal?

A: (A) Transverse! Light waves travel in an up and down motion.
Light waves are waves that travel on the electromagnetic spectrum. They are actually two types of waves travelling perpendicular to each other: electric waves and magnetic waves The electromagnetic spectrum gets its energy from the sun and other energy sources in our universe.

True or False: Microwaves in our kitchens work by using waves from the electromagnetic spectrum.

A: (A) True! There are 7 types of waves on the electromagnetic spectrum:
Radio Waves Microwaves, Infrared Visible light Ultraviolet X-rays Gamma *Visible light waves in the form of color are the only waves on the electromagnetic spectrum that we can see with our eyes.

True or False: All colors of visible light travel at the same wave frequency.
Remember that wave frequency is how many waves travel in a given location per second (in other words, how fast the waves travel!)

A: (B) False! Each color of visible light travels at a different frequency.

Q: If the sun emits different colors (waves) of visible, why do you think we only see white or “yellow” light in the sun? The sun only makes yellow light. The sun is too far away to see all of the colors it emits. When our eyes see all of the colors of visible light together, it looks like white light to us. Rainbows are only seen when they’re growing out of pots of gold.

A: (C) When our eyes see all of the colors of visible light together, it looks like white light to us. The reason we see certain objects as being certain colors, is because some object will absorb some of the colors of visible light, but not others. The object will then bounce back the colors that doesn’t absorb towards out eyes. Objects that appear white to us, absorb all of the colors of visible light.