What are Waves? Describing Waves Sound Sight Color - - PDF document

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4th Grade

Waves, Light & Information

2015-11-17 www.njctl.org

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· What are Waves?

Click on the topic to go to that section

· Sound · Sight · Color · Digitized Information · Describing Waves · Mirrors · Refraction

Slide 4 / 131

What are Waves?

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Slide 5 / 131 Where have you seen waves?

At the beach? On a guitar? At a baseball game?

Slide 6 / 131 What are Waves?

Each of these examples move up and down and across in a regular pattern (you never see just one wave at the beach). Can you think of any other times you see something moving like that?

Slide 6 (Answer) / 131 What are Waves?

Each of these examples move up and down and across in a regular pattern (you never see just one wave at the beach). Can you think of any other times you see something moving like that? Teacher Notes

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Students might bring up a slinky, holding on to a rope and wiggling it, waves coming from a moving boat,

• etc. Some might also talk about

light or sound.

Slide 7 / 131 Water Waves

After dropping a rock or other object into the water basin you should have seen something like the image above. We're now going to make some waves of our own. Your teacher should have a basin filled with water.

Slide 7 (Answer) / 131 Water Waves

After dropping a rock or other object into the water basin you should have seen something like the image above. We're now going to make some waves of our own. Your teacher should have a basin filled with water. Teacher Notes

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This is the water wave in a basin and a wave in a rope demo. Fill a basin with water and drop a rock into it. You can see as the waves move outward from that point. For the rope, hold it at one end and move the other end up and down.

Slide 8 / 131 Water Waves

Here is a simulation of what we just saw. Can you see the waves moving out from the lower left corner? What started these waves moving?

Slide 8 (Answer) / 131 Water Waves

Here is a simulation of what we just saw. Can you see the waves moving out from the lower left corner? What started these waves moving? Teacher Notes

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An object, like a rock, was dropped into the water in the lower left corner- you can see the splash

Slide 9 / 131 Water Waves

Before the rock is dropped, the water is flat, calm, and not moving . The scientific word for that is equilibrium. Before we drop the rock, the water is in equilibrium.

Slide 10 / 131 Water Waves

The rock falls in the water, sinks, and pushes the water out of its

• way. This water goes up and over the surface and moves away

from the rock - this is a wave! The water is no longer in equilibrium, it is disturbed. The waves move in a nice pattern, repeating themselves!

Slide 11 / 131 Rope Waves

Here's a simulation (remember - it's a model that helps us understand how the real thing works) of the waves that were created in the rope lab. What disturbance created these waves? The light blue curvy line is a picture of the rope. Each little dot is just one point on the rope.

Slide 11 (Answer) / 131 Rope Waves

Here's a simulation (remember - it's a model that helps us understand how the real thing works) of the waves that were created in the rope lab. What disturbance created these waves? The light blue curvy line is a picture of the rope. Each little dot is just one point on the rope. Teacher Notes

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The rope was wiggled up and down. The wiggling is the disturbance - like the rock that was dropped in the water.

Slide 12 / 131 Rope Waves

Look at any dot on this simulation. Which way is that single dot moving? Right? Left? Up? Down?

Slide 12 (Answer) / 131 Rope Waves

Look at any dot on this simulation. Which way is that single dot moving? Right? Left? Up? Down? Teacher Notes

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The dots are moving up and down - they are not moving left to right, even though the wave is moving left to right. This is a tricky concept and we'll be talking more about this later.

Slide 13 / 131 Transverse Wave

The dot is moving up and down, as you can see in the simulation below. There is a special name for a wave where the individual dots move up and down. It's called a transverse wave. If this were a water wave, the dots would be little drops of water. If it were a rope wave, the dots would be the pieces of the rope moving up and down.

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1 Waves are regular patterns of motion that are caused by a disturbance. True False

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1 Waves are regular patterns of motion that are caused by a disturbance. True False

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Answer TRUE

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2 What kind of a disturbance will cause a water wave to start? A Listening to the water. B Dropping a rock into a basin of water. C Looking at the water.

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2 What kind of a disturbance will cause a water wave to start? A Listening to the water. B Dropping a rock into a basin of water. C Looking at the water.

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Answer B

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3 As you wiggle a rope, a transverse wave moves along the rope away from your hand. Which way does each piece of the rope move? A Up and down. B Outward from your hand C Inward towards your hand

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3 As you wiggle a rope, a transverse wave moves along the rope away from your hand. Which way does each piece of the rope move? A Up and down. B Outward from your hand C Inward towards your hand

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Answer A

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Describing Waves

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Slide 18 / 131 Describing Waves

Scientists like to name things - this helps them understand what is happening in the world and helps them invent new things. There are a lot of different names for waves!

Slide 19 / 131 Describing Waves

Let's begin by drawing a dotted line going through the center of a transverse wave (remember, this is a wave where the disturbance is going up and down as the wave moves left or right).

Slide 20 / 131 Equilibrium

The dotted line actually means something. If you were looking at a lake with no waves on it, would it look like that dotted line? What term did we learn which means when something is flat and calm?

Slide 20 (Answer) / 131 Equilibrium

The dotted line actually means something. If you were looking at a lake with no waves on it, would it look like that dotted line? What term did we learn which means when something is flat and calm? Teacher Notes

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The dotted line shows the water or rope is in equilibrium (calm) - and by moving up or down from the dotted line, the particles (water drops or pieces of the rope) are moving away from equilibrium.

Slide 21 / 131 Crest

All transverse waves have a crest. How many crests does this wave have? The crest is the highest point the wave reaches. Think of a crest like the top of a hill.

Slide 21 (Answer) / 131 Crest

All transverse waves have a crest. How many crests does this wave have? The crest is the highest point the wave reaches. Think of a crest like the top of a hill. Teacher Notes

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4 crests

Slide 22 / 131 Trough

The trough is the lowest point the wave reaches. All transverse waves also have a trough. How many troughs does this wave have?

Slide 22 (Answer) / 131 Trough

The trough is the lowest point the wave reaches. All transverse waves also have a trough. How many troughs does this wave have? Teacher Notes

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3 troughs

Slide 23 / 131 Describing Waves

Can you see that the wave goes above the dotted line (equilibrium) just as much as it goes below the line? Using the terms that we just learned, can you see that the ________ and the _________ are equally far away from the dotted line?

Slide 24 / 131 Amplitude

This distance from the dotted line (equilibrium) to the crest or the trough is called the amplitude of the wave. What do you notice about these two distances?

Slide 24 (Answer) / 131 Amplitude

This distance from the dotted line (equilibrium) to the crest or the trough is called the amplitude of the wave. What do you notice about these two distances? Teacher Notes

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The two distances are equal. The distance from the equilibrium line to the crest is the same as the distance from the equilibrium line to the trough.

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4 What do we call the top part of a wave? This is the point where the wave is the furthest distance above the equilibrium line. A Amplitude B Crest C Trough

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4 What do we call the top part of a wave? This is the point where the wave is the furthest distance above the equilibrium line. A Amplitude B Crest C Trough

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Answer B

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5 What do we call the bottom part of a wave? This is the point where the wave is the furthest distance below the equilibrium line. A Amplitude B Crest C Trough

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5 What do we call the bottom part of a wave? This is the point where the wave is the furthest distance below the equilibrium line. A Amplitude B Crest C Trough

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Answer C

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6 When we measure the distance from the equilibrium line to the crest or the trough, what do we call it? A Amplitude B Crest C Trough

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6 When we measure the distance from the equilibrium line to the crest or the trough, what do we call it? A Amplitude B Crest C Trough

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Answer A

Slide 28 / 131 Wavelength

Remember how we measured up and down in the wave and called it the amplitude? What if we measured side to side?

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7 Measuring a wave up and down gives wavelength, and measuring a wave side to side gives wavelength. True False

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7 Measuring a wave up and down gives wavelength, and measuring a wave side to side gives wavelength. True False

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Answer False

Slide 30 / 131 Time Behavior of Waves

We have been describing waves in terms of distances, but now we are going to look at their timing. Here we are only looking at the movement of the wave from left to right. Here we are looking at the individual pieces moving up and down. Do you see the difference?

Slide 30 (Answer) / 131 Time Behavior of Waves

We have been describing waves in terms of distances, but now we are going to look at their timing. Here we are only looking at the movement of the wave from left to right. Here we are looking at the individual pieces moving up and down. Do you see the difference? Teacher Notes

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These two waves are the same, we are just changing the way you look at them to explain new concepts.

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This time is the period.

Period

Below is a diagram of a wave with two arrows. These arrows are appropriately one wavelength away from each other. Using the timer to the right, determine how long it takes for the trough at the tip of the green arrow to hit the tip of the red arrow.

Slide 32 / 131 Period

The period is the time it takes for the wave to return to the same point. It is the time it takes for the trough (the lowest point of the wave) at the tip of the green arrow to hit the red arrow.

Slide 33 / 131 Period

After the wave completes one period, it has moved a distance of

• ne wavelength.

We just compared the time it takes for a wave to go somewhere (period) to the distance it traveled (wavelength)! measuring time = period measuring distance = wavelength

Slide 34 / 131 Frequency

Something else that is closely related to period is frequency. You probably know what frequency is but just have not applied it to science before. If you go to science class once per day, that is the frequency of your class.If you go to karate lessons twice per week, that is also a frequency. Frequency is the number of times something happens in a certain amount of time.

Slide 35 / 131 Frequency

Let's apply that idea to waves. The frequency is the number of wavelengths that pass a point within a certain unit of time. You just count the number of peaks (or troughs) that go by a point. If 3 peaks go by in one second, then the frequency is 3 per second.

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8 The distance between two crests of a wave that are next to each other is called: A frequency B amplitude C wavelength

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8 The distance between two crests of a wave that are next to each other is called: A frequency B amplitude C wavelength

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Answer C

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9 The distance between two troughs of a wave that are next to each other is called: A frequency B amplitude C wavelength

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9 The distance between two troughs of a wave that are next to each other is called: A frequency B amplitude C wavelength

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Answer C

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10 The number of wavelengths that pass a point in a certain time is called: A frequency B amplitude C wavelength

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10 The number of wavelengths that pass a point in a certain time is called: A frequency B amplitude C wavelength

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Answer A

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11 The part of the wave that doesn't go above or below the line, it stays on the line, is defined as: A the crest B the trough C equilibrium

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11 The part of the wave that doesn't go above or below the line, it stays on the line, is defined as: A the crest B the trough C equilibrium

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Answer C

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12 How many crests does this wave have?

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12 How many crests does this wave have?

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Answer 4

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13 How many troughs does this wave have?

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13 How many troughs does this wave have?

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Answer 3

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14 Which wave has the largest wavelength? A B C

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14 Which wave has the largest wavelength? A B C

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Answer C

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15 Which wave has the smallest wavelength? A B C

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15 Which wave has the smallest wavelength? A B C

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Answer B

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16 Which wave has the largest amplitude? A B C

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16 Which wave has the largest amplitude? A B C

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Answer A

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17 The crest is labeled _______.

A B C D E

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17 The crest is labeled _______.

A B C D E

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Answer B

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18 The wavelength is labeled _______.

A B C D E

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18 The wavelength is labeled _______.

A B C D E

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Answer E

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19 The equilibrium is labeled _______.

A B C D E

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19 The equilibrium is labeled _______.

A B C D E

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Answer A

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20 The trough is labeled _______.

A B C D E

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20 The trough is labeled _______.

A B C D E

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Answer C

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21 The amplitude is labeled _______.

A B C D E

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21 The amplitude is labeled _______.

A B C D E

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Answer D

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22 The time it takes to move one wavelength is known as the ___________. A period B frequency C amplitude D equilibrium time

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22 The time it takes to move one wavelength is known as the ___________. A period B frequency C amplitude D equilibrium time

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Answer A

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23 The number of times a wave moves one wave length in a given unit of time is the _________. A period B frequency C amplitude D equilibrium time

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23 The number of times a wave moves one wave length in a given unit of time is the _________. A period B frequency C amplitude D equilibrium time

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Answer B

Slide 52 / 131 Paper Wave Lab

When we measure side to side, we are looking at wavelength. The wavelength is the distance until the wave repeats itself (remember that a wave repeats itself because it moves in a pattern). In this lab you will create a wave using a repeating motion over a piece of paper. It is the distance from a crest to the next closest crest. It is the distance from a trough to the next closest trough.

wavelength wavelength wavelength

Slide 52 (Answer) / 131 Paper Wave Lab

When we measure side to side, we are looking at wavelength. The wavelength is the distance until the wave repeats itself (remember that a wave repeats itself because it moves in a pattern). In this lab you will create a wave using a repeating motion over a piece of paper. It is the distance from a crest to the next closest crest. It is the distance from a trough to the next closest trough.

wavelength wavelength wavelength

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Teacher Notes Some of your students may notice it is also the distance from any point to the next closet similar point on the next wave. This is the paper wave lab. Please access the following documents on the teacher section

• f the NJCTL website:

· Student worksheet · Solutions

Slide 53 / 131

Sound

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Slide 54 / 131 Sound

If you move your hand back and forth quickly with the palm of your hand facing your ear, do you hear something? (Make sure not to hit yourself!) How did you make sound in this case?

Slide 55 / 131 Sound

By moving your hand back and forth you are pushing the air between your hand and your ear. This movement creates a sound wave which will travel to your ear! Some of the kinetic energy from your hand moving is changing into sound energy, which is carried by this sound wave.

Slide 56 / 131 Air

The air around you is occupied by very small objects that we call

• particles. You can't see them, because they're too small!

These particles collide with one another transmitting the sound waves. You know the particles are there because you can see them if there is a haze.

Slide 57 / 131 Sound

Here is a simulation of this motion. The little dots are the air particles. The grey bar on the left side of the picture represents your hand pushing on the air. The sound wave then moves through the air through a series of collisions, until it reaches your ear where you can hear the sound.

Animation courtesy of Dr. Dan Russell, Grad. Prog. Acoustics, Penn State

Slide 58 / 131 Sound

Describe the motion of the black dots in the picture above. It might look like the vertical lines of black dots start on the left and go all the way to the right.

Animation courtesy of Dr. Dan Russell, Grad. Prog. Acoustics, Penn State

Slide 59 / 131 Sound

But now, just look closely at the red dots (this works for all the particles, however it's just easier to look at the red dots). They're moving to the right, then the left! And they wind up in the same place. So the dots (air particles) don't move all the way from the left to the right. How is this different from the water waves?

Animation courtesy of Dr. Dan Russell, Grad. Prog. Acoustics, Penn State

Slide 59 (Answer) / 131 Sound

But now, just look closely at the red dots (this works for all the particles, however it's just easier to look at the red dots). They're moving to the right, then the left! And they wind up in the same place. So the dots (air particles) don't move all the way from the left to the right. How is this different from the water waves?

Animation courtesy of Dr. Dan Russell, Grad. Prog. Acoustics, Penn State

Teacher Notes

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In the water waves, the particles move up and down as the wave moves to the right. For sound waves, the particles move to the right and left as the wave moves to the right.

Slide 60 / 131 Longitudinal Waves

The type of wave you are producing here is referred to as a longitudinal wave. In a longitudinal wave, the particles move in the same or opposite direction as the wave. Longitudinal waves also happen in other cases - not just sound waves. An easy way to demonstrate this is to use a slinky.

Slide 61 / 131 Longitudinal Waves

In the image below, we have an already stretched out slinky (the left side was attached to a hook and the person pulled it all the way out to the right). She then pushed and pulled on it. This created a longitudinal wave as shown above. Do you see the wave moving through the slinky?

Slide 62 / 131 Longitudinal Waves

With the sound wave in air, the air particles move back and forth as the wave travels. Sound waves are longitudinal waves. The motion of the coils in the slinky above are longitudinal waves. What's the same about sound longitudinal waves and slinky longitudinal waves? What's different?

Slide 62 (Answer) / 131 Longitudinal Waves

With the sound wave in air, the air particles move back and forth as the wave travels. Sound waves are longitudinal waves. The motion of the coils in the slinky above are longitudinal waves. What's the same about sound longitudinal waves and slinky longitudinal waves? What's different? Teacher Notes

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The little plastic coils of the slinky move left and then right, and return to their original position, while the wave continues moving to the left. For sound waves, the air particles do the same thing! But - you can see the slinky move

• you cannot see sound waves.

Slide 63 / 131 Longitudinal Waves

A longitudinal wave is made by hitting an object (making it vibrate) or by pushing back and forth on a material (like air or the slinky). A longitudinal wave needs to move through some form of matter, and if there is nothing to push on then the wave cannot move. What is the wave actually moving through in the slinky?

Slide 63 (Answer) / 131 Longitudinal Waves

A longitudinal wave is made by hitting an object (making it vibrate) or by pushing back and forth on a material (like air or the slinky). A longitudinal wave needs to move through some form of matter, and if there is nothing to push on then the wave cannot move. What is the wave actually moving through in the slinky? Teacher Notes

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Through the coils in the slinky.

Slide 64 / 131 Sound

Remember that longitudinal waves need something to move through. In science fiction movies, when a spaceship blows up in space, it typically makes a very loud sound. Can that actually happen? Is there air in space?

Slide 64 (Answer) / 131 Sound

Remember that longitudinal waves need something to move through. In science fiction movies, when a spaceship blows up in space, it typically makes a very loud sound. Can that actually happen? Is there air in space? Teacher Notes

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No! There is no air in space for the sound energy to push

• n.

Space is a vacuum; there is nothing in space!

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24 A sound wave is an example of a ___________ wave. A Transverse B Longitudinal

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24 A sound wave is an example of a ___________ wave. A Transverse B Longitudinal

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Answer B

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25 A water wave is an example of a ___________ wave. A Transverse B Longitudinal

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25 A water wave is an example of a ___________ wave. A Transverse B Longitudinal

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Answer A

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26 How would you make a longitudinal wave in a slinky? A Move one end up and down. B Move one end in a circle. C Move one end back and forth (compressing the slinky). D Do nothing to the slinky.

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26 How would you make a longitudinal wave in a slinky? A Move one end up and down. B Move one end in a circle. C Move one end back and forth (compressing the slinky). D Do nothing to the slinky.

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Answer C

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27 Where can sound not move? A In metal B In water C In air D In a vacuum

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27 Where can sound not move? A In metal B In water C In air D In a vacuum

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Answer D

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28 Why can't sound move in outer space? A there is no matter for the sound to move through B because it's a transverse wave

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28 Why can't sound move in outer space? A there is no matter for the sound to move through B because it's a transverse wave

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Answer A

Slide 70 / 131 Sound Lab

Let's now take some time to explore sound using a cup and a string.

Slide 70 (Answer) / 131 Sound Lab

Let's now take some time to explore sound using a cup and a string.

Teacher Notes

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This is the sound cup lab. Please access the following documents on the teacher section

• f the NJCTL website:

· Lab presentation · Student worksheet · Teacher notes

Slide 71 / 131 Sound

Sound waves are made by vibrating objects which then transfer energy. Different things were vibrating in this experiment. Can you name some of them?

Slide 71 (Answer) / 131 Sound

Sound waves are made by vibrating objects which then transfer energy. Different things were vibrating in this experiment. Can you name some of them?

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Answer Air, cups and string.

Slide 72 / 131 Sound

Let's do another experiment on sound, but this time we're going to make a 1-string guitar. Remember sound is a type of energy that travels in waves and transfers energy from one point to another. This time, instead of using our voice to start the waves, we're going to pluck a string with our fingers.

Slide 72 (Answer) / 131 Sound

Let's do another experiment on sound, but this time we're going to make a 1-string guitar. Remember sound is a type of energy that travels in waves and transfers energy from one point to another. This time, instead of using our voice to start the waves, we're going to pluck a string with our fingers. Teacher Notes

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This is the one string guitar lab. Please access the following documents on the teacher section

• f the NJCTL website:

· Lab presentation · Student worksheet · Teacher notes

Slide 73 / 131 Sound

When you pluck the guitar string you create a vibration in the string. This vibration is similar to the string-cup lab. What happened when you put the box next to the guitar string in the lab?

Slide 73 (Answer) / 131 Sound

When you pluck the guitar string you create a vibration in the string. This vibration is similar to the string-cup lab. What happened when you put the box next to the guitar string in the lab?

Slide 74 / 131 Sound

While playing with your one string guitar did you notice what happened as you move your hand down the guitar while plucking the string? If not, give it a try now. The sound didn't get louder but started to become higher pitched. What does "pitch" mean? Can you change the pitch of your own voice? Try it now.

Slide 75 / 131 Sound

Is a high pitch sound always louder then a low pitch sound? Girls usually sing with a higher pitch than boys. Does this mean they are always louder?

Slide 75 (Answer) / 131 Sound

Is a high pitch sound always louder then a low pitch sound? Girls usually sing with a higher pitch than boys. Does this mean they are always louder? Teacher Notes

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No, when changing the pitch of a sound, you are not changing how loud it is (its amplitude). You just change its frequency - the higher the frequency, the squeakier it sounds. The lower the frequency, the deeper it sounds.

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29 A deep sounding voice has a low pitch. True False

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29 A deep sounding voice has a low pitch. True False

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Answer True

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30 A high pitch can be louder than a low pitch. True False

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30 A high pitch can be louder than a low pitch. True False

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Answer True

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31 A low pitch can be louder than a high pitch. True False

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31 A low pitch can be louder than a high pitch. True False

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Answer True

Slide 79 / 131 Summary of Types of Waves

Label the two types of waves below. Transverse Wave Longitudinal Wave

Slide 80 / 131 Summary of Types of Waves

Transverse wave: the particles in the wave move up and down while the wave moves right or left. What type of waves did we say move like this?

Slide 81 / 131 Summary of Types of Waves

Longitudinal wave: moves by pushing stuff such as air, or from a vibrating object. The waves made by pushing on a slinky (one that is already stretched out) are longitudinal waves. What other type of waves did we say were longitudinal?

Slide 82 / 131

Sight

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Slide 83 / 131 Sight

If we have all the lights turned off can you see anything? If all the lights are on, can you see then? So, why can you see things? What must you have in order to see?

Slide 84 / 131 Light

We can only see an object when light is present. Sources of light, such as the sun or a lightbulb, give off rays of light.

Slide 85 / 131 Light

In years past in science, we learned these rays of light will continue to travel in straight paths until they collide with something. The the light is either reflected, absorbed, or bent.

Slide 86 / 131 Sight

In order to see the box you need to have light rays striking its surface and being reflected.

Slide 86 (Answer) / 131 Sight

In order to see the box you need to have light rays striking its surface and being reflected. Teacher Notes

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Show how the light is coming from the Sun at the top left, bounces off the box, and then enters the person's eye at the lower left.

Slide 87 / 131 Sight

When no light rays strike the surface there is nothing to be reflected towards your eye, therefore you cannot see.

nothing is reflected

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32 In order to see we need ___________. A the lights off B the lights on

Slide 88 (Answer) / 131

32 In order to see we need ___________. A the lights off B the lights on

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Answer B

Slide 89 / 131

Color

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Slide 90 / 131 Color

So far we have covered what it means to see an object. You need light rays to strike an object and be reflected towards your eyes so you can see it. But why do we see color? What makes one object appear a different color then another? Talk about this for a minute with a partner.

Slide 91 / 131 Color

The color of an object is determined by the light that is absorbed and reflected off its surface. All of the colors are contained within a beam of white light, such as those from the sun or a light bulb.

Slide 92 / 131 Prism and a Rainbow

When we passed a beam of white light through a glass prism we saw the following colors: Red, Orange, Yellow, Green, Blue, Indigo, and Violet This is also how a rainbow is formed! What does the light pass through when a rainbow occurs?

Slide 92 (Answer) / 131 Prism and a Rainbow

When we passed a beam of white light through a glass prism we saw the following colors: Red, Orange, Yellow, Green, Blue, Indigo, and Violet This is also how a rainbow is formed! What does the light pass through when a rainbow occurs? Teacher Notes

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Glass Prism:

Slide 93 / 131 Color

The colors that you see are a result of the absorption of certain colors and the reflection of others.

Reflected

The tree appears green because the rest of the colors are absorbed and

• nly the color

green is reflected to your eye.

Slide 93 (Answer) / 131 Color

The colors that you see are a result of the absorption of certain colors and the reflection of others.

Reflected

The tree appears green because the rest of the colors are absorbed and

• nly the color

green is reflected to your eye. Teacher Notes

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Point out how we're showing the white light as a combination of all the colors - then after it hits the tree, the tree absorbs all of the colors, except green. And this light is reflected (more on reflection next unit) to the person's eyes, so the tree looks green.

Slide 94 / 131

33 What can be used to split white light into other colors? A a rock B a mirror C a rainbow D a prism

Slide 94 (Answer) / 131

33 What can be used to split white light into other colors? A a rock B a mirror C a rainbow D a prism

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Answer D

Slide 95 / 131

34 This square appears blue because: A only the color blue is absorbed and the rest of the colors are reflected B only the color blue is reflected and the rest of the colors are absorbed

Slide 95 (Answer) / 131

34 This square appears blue because: A only the color blue is absorbed and the rest of the colors are reflected B only the color blue is reflected and the rest of the colors are absorbed

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Answer B

Slide 96 / 131

35 If white light means having all the colors, what color do you see if everything is absorbed and nothing is reflected (hint - what do you see if there are no colors)? A Yellow B Black C Blue D Red

Slide 96 (Answer) / 131

35 If white light means having all the colors, what color do you see if everything is absorbed and nothing is reflected (hint - what do you see if there are no colors)? A Yellow B Black C Blue D Red

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Answer B

Slide 97 / 131

Mirrors

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• f Contents

Slide 98 / 131 Plane Mirror Lab

When you look directly at a mirror you seen an image as if it appears on the other side. How far away is that image from the mirror?

Slide 98 (Answer) / 131 Plane Mirror Lab

When you look directly at a mirror you seen an image as if it appears on the other side. How far away is that image from the mirror? Teacher Notes

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This is the plane mirror lab. Please access the following documents on the teacher section

• f the NJCTL website:

· Lab presentation · Student worksheet · Teacher notes

Slide 99 / 131 Light Reflection Lab

When a beam of light hits the surface

• f a mirror at an angle, at what angle

will it be reflected? As you probably know, a mirror will reflect light.

Slide 99 (Answer) / 131 Light Reflection Lab

When a beam of light hits the surface

• f a mirror at an angle, at what angle

will it be reflected? As you probably know, a mirror will reflect light. Teacher Notes

[This object is a teacher notes pull tab]

This is the light reflection lab. Please access the following documents on the teacher section

• f the NJCTL website:

· Lab presentation · Student worksheet · Teacher notes

Slide 100 / 131

36 In the diagram below, which path will the reflected beam take?

a b c incoming ray

Slide 100 (Answer) / 131

36 In the diagram below, which path will the reflected beam take?

a b c incoming ray

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Answer B

Slide 101 / 131 Reflection

The beam of light will be reflected along path b. It leaves at the same angle that it hit the mirror's surface.

b

Slide 102 / 131

37 Where will the image appear when looking into the mirror? Position A, B, or C?

• bject

mirror

A

B C

Slide 102 (Answer) / 131

37 Where will the image appear when looking into the mirror? Position A, B, or C?

• bject

mirror

A

B C

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Answer B

Slide 103 / 131 Reflection

The object will appear at position B, it will be as far back in the mirror as it is in front of it. mirror

• bject

B

Slide 104 / 131 Mirrors

How many different types of mirrors are there? Have you noticed any of them in your daily lives? If so, where were they?

Slide 105 / 131 Mirrors

There are three different types of mirrors: Plane Mirror Convex Mirror Concave Mirror

Slide 106 / 131 Plane Mirrors

A plane mirror has a flat reflective surface. It shows a normal sized image that isn't distorted. An example would be a normal mirror on a wall

Slide 107 / 131 Convex Mirrors

A convex mirror has a bump in the reflective surface which reflects light over greater angles. An example would be the mirrors on the side of a car.

Slide 108 / 131 Concave Mirrors

Concave Mirrors have an indent in the reflective surface, it causes light to focus more at one point. An example would be the mirror in a flashlight.

Slide 109 / 131 Mirrors

This year, we are only going to talk about the plane mirror. If you are interested in seeing what a concave and convex mirror do to an image, when you get home look at your reflection on both sides of a metal spoon. Make sure you change how far away you are from the spoon. You may have to nearly touch one surface in order to see something cool happen!

Slide 109 (Answer) / 131 Mirrors

This year, we are only going to talk about the plane mirror. If you are interested in seeing what a concave and convex mirror do to an image, when you get home look at your reflection on both sides of a metal spoon. Make sure you change how far away you are from the spoon. You may have to nearly touch one surface in order to see something cool happen! Teacher Notes

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On the convex side of the spoon, your image will be distorted and be right side up. In the concave side of the spoon, your image will be distorted and upside down as you are far away, but when you get really close to the mirror, the image will be much larger and facing rightside up.

Slide 110 / 131 Plane Mirror

A plane mirror can be used simply to look at yourself while you are brushing your or doing your hair. Since a plane mirror does not change the way you look in the mirror, it is the best thing to look at. Also, remember that a plane mirror reflects light at the same angle it reaches the mirror. Look at the examples below to see this.

Slide 111 / 131

Slide 111 (Answer) / 131 Slide 112 / 131 Slide 112 (Answer) / 131 Slide 113 / 131

Refraction

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Slide 114 / 131 Refraction

As we mentioned before, light rays can be reflected, absorbed, and also bent. Have you ever put a straw or pencil in a glass of water? Did anything seem odd? If we were to put the ruler into the water what would we see?

Slide 114 (Answer) / 131 Refraction

As we mentioned before, light rays can be reflected, absorbed, and also bent. Have you ever put a straw or pencil in a glass of water? Did anything seem odd? If we were to put the ruler into the water what would we see? Teacher Notes

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Refraction demo. Fill a basin with water and hold a ruler so part of it is submersed. You and your students should see that the ruler appears bent.

Slide 115 / 131 Refraction

When the ruler is place in the water it seems to have bent, so what is happening here? Does the ruler actually bend when being placed in the water?

Slide 116 / 131 Refraction

The ruler is just fine. It hasn't changed. Instead, we are looking at refraction, or the bending of light. The light coming from beneath the water is being bent in such a way that it appears as if something happened to the ruler.

Slide 117 / 131

Light bends as it passes from one material to another. Passing through water as well as other materials into air results in the bending of the light rays.

Refraction

Objects that use refraction include magnifying glasses and binoculars!

Slide 118 / 131

Digitized Information

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• f Contents

Slide 119 / 131 Communications

When we want to talk to family or friends, we are able to simply pick up a phone, dial a number, and speak into it. Communicating was not always like that. In ancient times the means of communicating were as basic as writing a letter and giving it to someone who would run great distances to deliver the message.

Slide 120 / 131 Communications

Can you come up with other ways people could have communicated over large distances a long time ago? We have talked about this in science before. Drumming is one example.

Slide 121 / 131 Communications

In today's day and age information can now be transmitted through waves. There are many devices that allow you to communicate today. Can you name

• thers?

Slide 121 (Answer) / 131 Communications

In today's day and age information can now be transmitted through waves. There are many devices that allow you to communicate today. Can you name

• thers?

Teacher Notes

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Cellphones, telephones, computers, radio, and so on.

Slide 122 / 131 Digitized Information

Many devices utilize waves in order to transmit information. For example, when you talk into the microphone on a cellphone it registers the sound waves coming from your mouth. It is then turned into an electrical signal and transmitted to another phone where it is converted back into sound waves. A similar process takes place in a radio.

Slide 123 / 131 Digitized Information

Just as we communicate through different languages, whether it is English, Spanish, French and so many others, computers also have their own language known as Binary. Instead of words, computers communicate through a list of 1's and 0's, by turning different parts inside the computer on and off. Did you realize your cellphone, video game boxes, PCs, and tablets are all different types of computers?

Slide 124 / 131 Digitized Information

Let's say we give you a set of numbers (100010001, for example), and told you to put them into a 3x3 grid as if your were writing on a piece of paper. Then let's say that the number 1 in each box means its a black square and any box that contains a 0 is white. The image would look like the following:

1 1 1

Slide 125 / 131 Digitized Information

If we give you a set of numbers: 000000000010101110010100100011100100 01010010001010111 0000000000 and told you to put them into a 7x9 grid as if your were writing on a piece of paper, what would the image read?

Slide 126 / 131 Digitized Information

This means of sharing information is rather simple. Another nice example is Morse Code. Morse code is comprised

• f a series of either short and long signals.

Using Morse Code, you can communicate with one of your friends simply by taping on a table or flashing a light in a certain combination. For example: If you flashed the light quickly three times, then three times slowly, and then again three times quickly, you would have sent

• ut the message SOS, a distress signal.

Slide 127 / 131 Digitized Information Slide 127 (Answer) / 131 Digitized Information

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Here is a cool website where you can translate text into morse code and play the message! http://morsecode.scphillips.com/ jtranslator.html

Slide 128 / 131 Slide 128 (Answer) / 131 Slide 129 / 131

39 The language of computers that works using zeros and

• nes is called __________.

A Morse Code B Binary C Coding D Os and 1s

Slide 129 (Answer) / 131

39 The language of computers that works using zeros and

• nes is called __________.

A Morse Code B Binary C Coding D Os and 1s

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Answer B

Slide 130 / 131

40 Cellphones use waves to communicate. True False

Slide 130 (Answer) / 131

40 Cellphones use waves to communicate. True False

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Answer TRUE

Slide 131 / 131 Binary Code Lab

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

Teacher Notes