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1st Grade

Waves

2015-11-20

www.njctl.org

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Table of Contents

· What are Waves?Click on the topic to go to that section

· Sound

· Sight

· What Happens When Light Hits Certain Objects

· Communication

· Shadows

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What are Waves?

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What are Waves?

Have you ever been at a beach or a lake and watched the water move up and down and across the shore?

Have you listened to someone playing a violin or a guitar and watch the strings move up and down and across?

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What are Waves?In both of those cases, you are seeing waves! The water in the ocean and the string of the guitar move up and down or 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?

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Waves DemoNow we are going to make some waves of our own. If you look down on a bucket full of water, this is what it looks like.

The water in the bucket is calm, nothing is moving.

But what happens if you drop a rock into the bucket?

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Water Waves

After you dropped the rock, did you see something like this?

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Water Waves

wavesThe rock hit the water here!

The bumps in the water are the wave moving away from where the rock hit the surface of the water.

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Water Waves

Up

Down

Waves cause an up and down motion in the water.

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Water WavesIt's easier to see this up and down motion here.

The red line shows when the water was calm or flat. Can you see that the wave goes above the red line as well as

below it?

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1 Can you find waves anywhere other than the beach?

Yes

No

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Sound

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Waves & Sound Activity

Sound is another type of wave, and these are the waves that we hear as music or people talking or just plain noise!

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Tuning Fork

Handle(Hold it here)

Hit this end against hard

object

What happens when you hit the tuning fork against your desk?

Tuning forks are pieces of metal which can make different sounds when hit.

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Tuning Fork

Sound needs something to move through. It moves the "something" very fast up and down or backwards and forwards. This is called a vibration. We can hear this

vibration as a sound.

What is the "something" which sound moves through?

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Tuning Fork

You should hear something after you hit the tuning fork against the desk. You should hear a sound!

This sound comes from the vibration, the movement of the tuning fork! How can you prove the end of the tuning fork is vibrating and that it is making the sound?

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Tuning Fork

After hitting the tuning fork against the desk, if you grab this end,

you should feel the vibrations!

Try it!

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Tuning Fork

You can also touch the end to a basin of water and see the waves that it will make from hitting the water.

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Tuning Fork

By playing with the tuning forks, you should be able to prove for yourself that the sound comes from the

movement in the one end of the fork.

When you grabbed the end to feel the vibrations, what did you notice happened to the sound and the

vibrations?

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Tuning Fork

So a tuning fork can produce a sound through vibrations.

In this picture, what's different about each of these tuning forks?

Do you think they will all sound the same?

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Pitch

So the longer tuning forks will make a lower pitch and the shorter ones will make a higher pitch.

Do you know what "pitch" is?

Play with each of the tuning forks and describe what you hear. Each has a different pitch.

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PitchIf you are still confused about what pitch is, let us try to define it in another way.

Look at these two dogs.

What do you think each of their barks would sound like?

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PitchThe big dog will probably have a deep bark! The puppy will

probably have a high squeaky bark!

Even though both dogs can bark, their barks will have different pitches.

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Pitch

Can you make a sentence which relates this picture to what you have learned about pitch?

Slide 28 / 912 Using the ruler given on the right, which tuning fork will

give a higher pitch (which is shortest)?

AB

CD

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3 Using the ruler given on the right, which tuning fork will give a lower pitch (which is longest)?

A B

C

D

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Sound

Can you name some other objects that make sound by vibrating?

We mentioned a guitar in the

beginning of this unit.

Are there any other instruments that

vibrate?

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Sound

So far we have shown that moving a tuning fork and hitting an object causes vibrations and sound, but can it

work in reverse?

Can your speakers or ear buds cause an object to

move?

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Sight

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Sight: Cave Explorer Activity

Let us explore the ability of sight.

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Sight

If we have all the lights turned off

in the classroom, can you see

anything?

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Sight

So if it's dark and you cannot see anything what do you do so you can see?

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Sight

If all the lights are

on, can you see?

So, what must we have so we can see?

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Light

We can only see an object when there is light.

Can you name other sources of light besides this bulb?

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Light

Rays of light will move in straight paths until they hit something else.

Light can be reflected (bounce off of something) or be absorbed (like a sponge soaking up water)

rays of light moving in a straight path

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Sight

In order to see a box, you need to have light rays hit the surface of the box and bounce back (be reflected) towards your eye!

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Sight

As we said before, if there were no light, you would not be able to see the box.

Nothing would be reflected towards your eye and you could not see the box.

nothing is reflected

This is why we cannot see in the dark!

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4 In order for our eyes to work, we need _________.

A sound

B movement

C light

D glasses

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What Happens When Light Hits Certain Objects

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Light hitting objects

In your everyday lives what are some things that light hits or passes through?

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Objects in Light's Path LabIn science, we like to list things, so we can understand

what's going on.

Light hits 4 different types of objects and acts differently with each one. Here they are:

Transparent Objects

Translucent Objects

Opaque Objects

Reflective Objects

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Transparent Transparent means something that is clear and allows all light to pass through it. The glass in most windows is transparent.

In the image you can see what it looks like outside the window.

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Transparent ALL light passes through a transparent object.

Light before hitting transparent object

Light after hitting transparent object

transparent object

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Translucent

Only some of the light passes through a translucent object. Here's two examples.

In these images you can sort of tell what is behind the translucent blocks, but you cannot see clearly.

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Translucent

The only way to tell this person is wearing a black and gray striped shirt is by looking here.

The rest of the person behind the blocks is difficult to see.

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Translucent

SOME light passes through a translucent object.

Light before hitting translucent object

Light after hitting translucent object

translucent object

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Opaque

None of the light hitting an opaque object passes through.

A box is opaque.

If you placed an object in a closed cardboard box, would your friend be able to see what you placed inside of box?

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Opaque

NO light passes through an opaque object.

Light before hitting opaque object

Light after hitting opaque object

opaque object

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5 The section that is TRANSPARENT is labeled _______.

A

B

C

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6 The section that is OPAQUE is labeled _______.

A

B

C

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7 The section that is TRANSLUCENT is labeled _______.

A

B

C

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Opaque

Translucent

Transparent

8 A red box is placed behind another material. Describe the material in front of the box.

A

B

C

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Opaque

Translucent

Transparent

9 A red box is placed behind another material. Describe the material in front of the box.

A

B

C

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Opaque

Translucent

Transparent

10 A red box is placed behind another material. Describe the material in front of the box.

A

B

C

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ReflectiveAll the light hitting a reflective object bounces off the

surface. It is like throwing a ball at a wall and having it come back to you. A mirror is a reflective surface.

Here we see two kittens, because the one to the right is the reflection from the mirror!

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Reflective

ALL the light bounces off a reflective surface.

Light before hitting reflective object

reflective object

Light after hitting reflective object

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Shadows

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Shadows

What is a shadow?

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Shadows

What will the shadow of an opaque object look like?

Light before hitting opaque object

Light after hitting opaque object

opaque object

?

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Shadows

When the light hits the opaque object nothing will pass through and it will form a dark shadow on the other side!

Light before hitting opaque object

Light after hitting opaque object

opaque object Shadow!

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Shadows

What will the shadow of a translucent object look like?

Light before hitting translucent object

Light after hitting translucent object

translucent object

?

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ShadowsWhen the light hits the translucent object some of the light

will pass through and it will form a shadow on the other side, but it wont be as dark!

Light before hitting translucent object

Light after hitting translucent object

translucent object Shadow!

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Shadows

Will a transparent object form a shadow?

Light before hitting transparent object

Light after hitting transparent object

transparent object?

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Shadows

No, the transparent object would not have formed a shadow, all the light passes through!

Light before hitting transparent object

Light after hitting transparent object

transparent object

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Communication

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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.

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Communications

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.

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CommunicationsOther means included setting fires to signal certain messages, perhaps the lookout on top of a mountain would set a fire to warn the village below of a possible attack.

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CommunicationsThe drumming of certain villages could be used to send messages over great distances.

Each rhythm and beat could represent a certain message which others would be able to recognize.

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String Phone Lab

You can make a very basic phone using only a couple of styrofoam cups and a string!

Give it a try!

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Communication

Not only can we communicate by talking to one another. We can also communicate through patterns, colors, and lights.

Can you think of some other examples?

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Communication

You could have listed flashing a light, smoke signals like they used to do in the old days, but one of my favorite examples is a traffic light!

What does a traffic light communicate?

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11 The light meaning STOP is labeled _____.

A

B

C

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12 The light meaning GO is labeled _____.

A

B

C

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13 The light meaning SLOW DOWN is labeled _____.

A

B

C

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Communication

As a fun classroom activity, you can all play the game red light, green light. Your teacher will have both a red light and

a green light which they can turn off and on.

You are only allowed to move when the light is green, GO!!!

You can not move when the light is red, you have to STOP!!!

You have to see who can make it all the way across the room.

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