4th Grade Waves, Light & Information

Transcription

1 Slide 1 / 131

2 Slide 2 / 131 4th Grade Waves, Light & Information

3 Slide 3 / 131 Table of Contents What are Waves? Describing Waves Sound Click on the topic to go to that section Sight Color Mirrors Refraction Digitized Information

4 Slide 4 / 131 What are Waves? Return to Table of Contents

5 Slide 5 / 131 Where have you seen waves? At the beach? On a guitar? At a baseball game?

6 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?

7 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). Teacher Notes 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. [This object is a teacher notes pull tab] Can you think of any other times you see something moving like that?

8 Slide 7 / 131 Water Waves We're now going to make some waves of our own. Your teacher should have a basin filled with water. After dropping a rock or other object into the water basin you should have seen something like the image above.

9 Slide 7 (Answer) / 131 Water Waves We're now going to make some waves of our own. Your teacher should have a basin filled with water.teacher Notes 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. [This object is a teacher notes pull tab] After dropping a rock or other object into the water basin you should have seen something like the image above.

10 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?

11 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? Teacher Notes What started these waves moving? An object, like a rock, was dropped into the water in the lower left corner- you can see the splash [This object is a teacher notes pull tab]

12 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.

13 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!

14 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.

15 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. Teacher Notes What disturbance The rope created was wiggled these up waves? and down. The wiggling is the disturbance - like the rock that was dropped in the water. [This object is a teacher notes pull tab] The light blue curvy line is a picture of the rope. Each little dot is just one point on the rope.

16 Slide 12 / 131 Rope Waves Look at any dot on this simulation. Which way is that single dot moving? Right? Left? Up? Down?

17 Slide 12 (Answer) / 131 Rope Waves Look at any dot on this simulation. Teacher Notes Which way is that single dot moving? The Right? dots are Left? moving up and down - they Up? are Down? 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. [This object is a teacher notes pull tab]

18 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.

19 Slide 14 / Waves are regular patterns of motion that are caused by a disturbance. True False

20 Slide 14 (Answer) / Waves are regular patterns of motion that are caused by a disturbance. True False Answer TRUE [This object is a pull tab]

21 Slide 15 / 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.

22 Slide 15 (Answer) / What kind of a disturbance will cause a water wave to start? A Listening to the water. Answer B Dropping a rock into a basin of water. C Looking at the water. B [This object is a pull tab]

23 Slide 16 / 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

24 Slide 16 (Answer) / 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. Answer B Outward from your hand C Inward towards your hand A [This object is a pull tab]

25 Slide 17 / 131 Describing Waves Return to Table of Contents

26 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!

27 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).

28 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?

29 Slide 20 (Answer) / 131 Equilibrium Teacher Notes 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 The dotted line actually moving means away something. from equilibrium. 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 [This object means is a teacher when notes pull something tab] is flat and calm?

30 Slide 21 / 131 Crest All transverse waves have a crest. The crest is the highest point the wave reaches. Think of a crest like the top of a hill. How many crests does this wave have?

31 Slide 21 (Answer) / 131 Crest All transverse waves have a crest. The crest is the highest point the wave reaches. Think of a crest like the top of a hill. Teacher Notes 4 crests [This object is a teacher notes pull tab] How many crests does this wave have?

32 Slide 22 / 131 Trough All transverse waves also have a trough. The trough is the lowest point the wave reaches. How many troughs does this wave have?

33 Slide 22 (Answer) / 131 Trough All transverse waves also have a trough. The trough is the lowest point the wave reaches. Teacher Notes 3 troughs [This object is a teacher notes pull tab] How many troughs does this wave have?

34 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?

35 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?

36 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. Teacher Notes 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. [This object is a teacher notes pull tab] What do you notice about these two distances?

37 Slide 25 / 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

38 Slide 25 (Answer) / 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 Answer B [This object is a pull tab]

39 Slide 26 / 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

40 Slide 26 (Answer) / 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 Answer C [This object is a pull tab]

41 Slide 27 / 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

42 Slide 27 (Answer) / 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 Answer A [This object is a pull tab]

43 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?

44 Slide 29 / Measuring a wave up and down gives wavelength, and measuring a wave side to side gives wavelength. True False

45 Slide 29 (Answer) / Measuring a wave up and down gives wavelength, and measuring a wave side to side gives wavelength. True False Answer False [This object is a pull tab]

46 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 looking at the individual pieces moving up and down. Here we are only looking at the movement of the wave from left to right. Do you see the difference?

47 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. Teacher Notes These two waves are the same, we are just changing the way you look at them to explain new concepts. Here we are looking at the individual pieces moving up and down. Here we are only looking at the movement of the wave from left to right. [This object is a teacher notes pull tab] Do you see the difference?

48 Slide 31 / 131 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. This time is the period.

49 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.

50 Slide 33 / 131 Period After the wave completes one period, it has moved a distance of one 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

51 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.

52 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.

53 Slide 36 / The distance between two crests of a wave that are next to each other is called: A frequency B amplitude C wavelength

54 Slide 36 (Answer) / The distance between two crests of a wave that are next to each other is called: A frequency B amplitude C wavelength Answer C [This object is a pull tab]

55 Slide 37 / The distance between two troughs of a wave that are next to each other is called: A frequency B amplitude C wavelength

56 Slide 37 (Answer) / The distance between two troughs of a wave that are next to each other is called: A frequency B amplitude C wavelength Answer C [This object is a pull tab]

57 Slide 38 / The number of wavelengths that pass a point in a certain time is called: A frequency B amplitude C wavelength

58 Slide 38 (Answer) / The number of wavelengths that pass a point in a certain time is called: A frequency B amplitude C wavelength Answer A [This object is a pull tab]

59 Slide 39 / 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

60 Slide 39 (Answer) / 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 Answer C [This object is a pull tab]

61 Slide 40 / How many crests does this wave have?

62 Slide 40 (Answer) / How many crests does this wave have? Answer 4 [This object is a pull tab]

63 Slide 41 / How many troughs does this wave have?

64 Slide 41 (Answer) / How many troughs does this wave have? Answer 3 [This object is a pull tab]

65 Slide 42 / Which wave has the largest wavelength? A B C

66 Slide 42 (Answer) / Which wave has the largest wavelength? A B Answer C C [This object is a pull tab]

67 Slide 43 / Which wave has the smallest wavelength? A B C

68 Slide 43 (Answer) / Which wave has the smallest wavelength? A B Answer B [This object is a pull tab] C

69 Slide 44 / Which wave has the largest amplitude? A B C

70 Slide 44 (Answer) / Which wave has the largest amplitude? A Answer A B [This object is a pull tab] C

71 Slide 45 / The crest is labeled. B D A C E

72 Slide 45 (Answer) / The crest is labeled. B Answer D B A C [This object is a pull tab] E

73 Slide 46 / The wavelength is labeled. B D A C E

74 Slide 46 (Answer) / The wavelength is labeled. B Answer DE A C [This object is a pull tab] E

75 Slide 47 / The equilibrium is labeled. B D A C E

76 Slide 47 (Answer) / The equilibrium is labeled. B Answer DA A C [This object is a pull tab] E

77 Slide 48 / The trough is labeled. B D A C E

78 Slide 48 (Answer) / The trough is labeled. B Answer DC A C E[This object is a pull tab]

79 Slide 49 / The amplitude is labeled. B D A C E

80 Slide 49 (Answer) / The amplitude is labeled. B Answer D D A C E [This object is a pull tab]

81 Slide 50 / The time it takes to move one wavelength is known as the. A period B frequency C amplitude D equilibrium time

82 Slide 50 (Answer) / The time it takes to move one wavelength is known as the. A period B frequency C amplitude Answer A D equilibrium time [This object is a pull tab]

83 Slide 51 / 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

84 Slide 51 (Answer) / The number of times a wave moves one wave length in a given unit of time is the. A period B frequency C amplitude Answer B D equilibrium time [This object is a pull tab]

85 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. wavelength wavelength wavelength It is the distance from a crest to the next closest crest. It is the distance from a trough to the next closest trough.

86 Slide 52 (Answer) / 131 Paper Wave Lab Some of your students may notice it When we measure is also side the to distance side, we from are any looking point at wavelength. to the next closet similar point on The wavelength the is next the wave. distance until the wave repeats itself (remember that a wave repeats itself because it moves in a pattern). In this This lab is you the will paper create wave a lab. wave using a repeating motion over a piece of paper. Please access the following documents wavelength on the teacher section of the NJCTL website: wavelength Teacher Notes Student worksheet Solutions [This object is a pull tab] wavelength It is the distance from a crest to the next closest crest. It is the distance from a trough to the next closest trough.

87 Slide 53 / 131 Sound Return to Table of Contents

88 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?

89 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.

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

91 Slide 57 / 131 Sound Here is a simulation of this motion. The little dots are the air particles. Animation courtesy of Dr. Dan Russell, Grad. Prog. Acoustics, Penn State 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.

92 Slide 58 / 131 Sound Animation courtesy of Dr. Dan Russell, Grad. Prog. Acoustics, Penn State 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.

93 Slide 59 / 131 Sound Animation courtesy of Dr. Dan Russell, Grad. Prog. Acoustics, Penn State 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?

94 Slide 59 (Answer) / 131 Sound Teacher Notes In the water waves, the particles move up and down as the wave But now, just look closely moves at the to red the dots right. (this For works sound for all the particles, however it's waves, just easier the particles to look move at the to red the dots). right and left as the wave moves to They're moving to the right, 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. Animation courtesy of Dr. Dan Russell, Grad. Prog. Acoustics, Penn State [This object is a teacher notes pull tab] How is this different from the water waves?

95 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.

96 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?

97 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?

98 Slide 62 (Answer) / 131 Longitudinal Waves With the sound wave in air, the air particles move back and forth as the wave travels. 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. Teacher Notes Sound waves are longitudinal waves. [This object is a teacher notes pull tab] 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?

99 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?

100 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. Teacher Notes Through the coils in the slinky. [This object is a teacher notes pull tab] What is the wave actually moving through in the slinky?

101 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?

102 Slide 64 (Answer) / 131 Sound Remember that longitudinal waves need something to move through. In science fiction No! movies, There is no air in space when a spaceship blows for the up sound in energy to push space, it typically makes on. a very loud sound. Space is a vacuum; there is Can that actually happen? nothing in space! Teacher Notes Is there air in space? [This object is a teacher notes pull tab]

103 Slide 65 / A sound wave is an example of a wave. A Transverse B Longitudinal

104 Slide 65 (Answer) / A sound wave is an example of a wave. A Transverse B Longitudinal Answer B [This object is a pull tab]

105 Slide 66 / A water wave is an example of a wave. A Transverse B Longitudinal

106 Slide 66 (Answer) / A water wave is an example of a wave. A Transverse B Longitudinal Answer A [This object is a pull tab]

107 Slide 67 / 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.

108 Slide 67 (Answer) / 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 Answer Move one end back and forth (compressing C the slinky). D Do nothing to the slinky. [This object is a pull tab]

109 Slide 68 / Where can sound not move? A In metal B In water C In air D In a vacuum

110 Slide 68 (Answer) / Where can sound not move? A In metal B In water C In air D In a vacuum Answer D [This object is a pull tab]

111 Slide 69 / 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

112 Slide 69 (Answer) / 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 Answer A [This object is a pull tab]

113 Slide 70 / 131 Sound Lab Let's now take some time to explore sound using a cup and a string.

114 Slide 70 (Answer) / 131 Sound Lab Let's now This take is the some sound time cup to lab. explore sound using a cup and a string. Teacher Notes Please access the following documents on the teacher section of the NJCTL website: Lab presentation Student worksheet Teacher notes [This object is a teacher notes pull tab]

115 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?

116 Slide 71 (Answer) / 131 Sound Sound waves are made by vibrating objects which then transfer energy. Air, cups and string. Answer Different things were vibrating in this experiment. Can you name some of them? [This object is a pull tab]

117 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.

118 Slide 72 (Answer) / 131 Sound Let's do another This is experiment the one string on guitar lab. sound, but this time we're going to make a Please 1-string access guitar. the following documents on the teacher section of the NJCTL website: Remember sound is a type of energy that travels in waves Lab presentation and transfers energy from one Student point to worksheet another. Teacher notes This time, instead of using our voice to start the waves, [This we're object is going a teacher to notes pull tab] pluck a string with our fingers. Teacher Notes

119 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?

120 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?

121 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.

122 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?

123 Slide 75 (Answer) / 131 Sound Is a high pitch sound always louder then a low pitch sound? No, when changing the pitch of a sound, you are not changing how loud it is (its amplitude). You just change its frequency - Girls usually sing with a the higher the frequency, the higher pitch than boys. squeakier it sounds. The lower the frequency, the deeper it sounds. Does this mean they are always louder? Teacher Notes [This object is a teacher notes pull tab]

124 Slide 76 / A deep sounding voice has a low pitch. True False

125 Slide 76 (Answer) / A deep sounding voice has a low pitch. True False Answer True [This object is a pull tab]

126 Slide 77 / A high pitch can be louder than a low pitch. True False

127 Slide 77 (Answer) / A high pitch can be louder than a low pitch. True False Answer True [This object is a pull tab]

128 Slide 78 / A low pitch can be louder than a high pitch. True False

129 Slide 78 (Answer) / A low pitch can be louder than a high pitch. True False Answer True [This object is a pull tab]

130 Slide 79 / 131 Summary of Types of Waves Label the two types of waves below. Transverse Wave Longitudinal Wave

131 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?

132 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?

133 Slide 82 / 131 Sight Return to Table of Contents

134 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?

135 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.

136 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.

137 Slide 86 / 131 Sight In order to see the box you need to have light rays striking its surface and being reflected.

138 Slide 86 (Answer) / 131 Sight Teacher Notes In order to see the box you need to have light rays striking its surface and being reflected. 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. [This object is a teacher notes pull tab]

139 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

140 Slide 88 / In order to see we need. A the lights off B the lights on

141 Slide 88 (Answer) / In order to see we need. A the lights off B the lights on Answer B [This object is a pull tab]

142 Slide 89 / 131 Color Return to Table of Contents

143 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.

144 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.

145 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?

146 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: Glass Prism: Red, Orange, Yellow, Green, Blue, Indigo, and Violet This is also how a rainbow is formed! Teacher Notes What does the light pass through when a rainbow occurs? [This object is a teacher notes pull tab]

147 Slide 93 / 131 Color The colors that you see are a result of the absorption of certain colors and the reflection of others. The tree appears green because the rest of the colors are absorbed and only the color green is reflected to your eye. Reflected

148 Slide 93 (Answer) / 131 Teacher Notes Color The colors that you see are a result of the absorption of certain colors and the reflection Point of out others. how we're showing the white light as a combination of all the colors - then after it hits the The tree appears tree, the tree absorbs all of the green because colors, except green. And this the rest of the light is reflected (more on reflection colors are next unit) to the person's eyes, so absorbed and the tree looks green. only the color green is reflected [This object is a teacher notes pull tab] to your eye. Reflected

149 Slide 94 / What can be used to split white light into other colors? A a rock B a mirror C a rainbow D a prism

150 Slide 94 (Answer) / What can be used to split white light into other colors? A a rock B a mirror C a rainbow D a prism Answer D [This object is a pull tab]

151 Slide 95 / 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

152 Slide 95 (Answer) / This square appears blue because: A B only the color blue is absorbed and the rest of the colors are reflected Answer only the color blue is reflected and the rest of the colors are absorbed B [This object is a pull tab]

153 Slide 96 / 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

154 Slide 96 (Answer) / 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 Answer B [This object is a pull tab]

155 Slide 97 / 131 Mirrors Return to Table of Contents

156 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?

157 Slide 98 (Answer) / 131 Plane Mirror Lab When you look This directly is the at plane a mirror mirror you lab. seen an image as if it appears on the other side. How far away is that image from the Please access mirror? the following documents on the teacher section of the NJCTL website: Teacher Notes Lab presentation Student worksheet Teacher notes [This object is a teacher notes pull tab]

158 Slide 99 / 131 Light Reflection Lab As you probably know, a mirror will reflect light. When a beam of light hits the surface of a mirror at an angle, at what angle will it be reflected?

159 Slide 99 (Answer) / 131 Light Reflection Lab Teacher Notes This is the light reflection lab. Please access the following documents on the teacher section of the NJCTL website: As you probably know, a mirror will reflect light. Lab presentation When a beam of Student light hits worksheet the surface of a mirror at an Teacher angle, at notes what angle will it be reflected? [This object is a teacher notes pull tab]

160 Slide 100 / In the diagram below, which path will the reflected beam take? incoming ray c b a

161 Slide 100 (Answer) / In the diagram below, which path will the reflected beam take? incoming ray Answer B c [This object is a pull tab] b a

162 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

163 Slide 102 / Where will the image appear when looking into the mirror? Position A, B, or C? mirror object A B C

164 Slide 102 (Answer) / Where will the image appear when looking into the mirror? Position A, B, or C? mirror Answer B object A B C [This object is a pull tab]

165 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 object B

166 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?

167 Slide 105 / 131 Mirrors There are three different types of mirrors: Plane Mirror Convex Mirror Concave Mirror

168 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

169 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.

170 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.

171 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!

172 Slide 109 (Answer) / 131 Mirrors This year, we are only going to talk about the plane mirror. On the convex side of the spoon, your image will be distorted and If you are interested in seeing be right what side a concave up. and convex mirror do to an image, when you get home look at your reflection on both sides of a metal spoon. In the concave side of the spoon, your image will be distorted and upside down as you are far away, Make sure you change how but far when away you you get are really from close the to spoon. You may have to nearly touch the one mirror, surface the in image order will to see be much something larger and facing rightside up. cool happen! Teacher Notes [This object is a teacher notes pull tab]

173 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.

174 Slide 111 / 131

175 Slide 111 (Answer) / 131

176 Slide 112 / 131

177 Slide 112 (Answer) / 131

178 Slide 113 / 131 Refraction Return to Table of Contents

179 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?

180 Slide 114 (Answer) / 131 Refraction As we mentioned before, light rays can be reflected, absorbed, Refraction and also demo. bent. Teacher Notes Have you ever put a Fill straw a basin or pencil with water in a glass and hold of water? a Did anything ruler so part seem of it odd? is submersed. You and your students should see that the ruler appears bent. If we were to put the ruler into the water what would we see? [This object is a teacher notes pull tab]

181 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?

182 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.

183 Slide 117 / 131 Refraction 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. Objects that use refraction include magnifying glasses and binoculars!

184 Slide 118 / 131 Digitized Information Return to Table of Contents

185 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.

186 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.

187 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 others?

188 Slide 121 (Answer) / 131 Communications In today's day and age information can now be transmitted through waves. Teacher Notes There are many devices that allow you to communicate today. Cellphones, telephones, computers, radio, and so on. Can you name others? [This object is a teacher notes pull tab]

189 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.

190 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?

191 Slide 124 / 131 Digitized Information Let's say we give you a set of numbers ( , 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:

192 Slide 125 / 131 Digitized Information If we give you a set of numbers: 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?

193 Slide 126 / 131 Digitized Information This means of sharing information is rather simple. Another nice example is Morse Code. Morse code is comprised of 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 out the message SOS, a distress signal.

194 Slide 127 / 131 Digitized Information

195 Slide 127 (Answer) / 131 Digitized Information e is a cool website where you can slate text into morse code and play message! ://morsecode.scphillips.com/ nslator.html [This object is a teacher notes pull tab]

196 Slide 128 / 131

197 Slide 128 (Answer) / 131

198 Slide 129 / The language of computers that works using zeros and ones is called. A Morse Code B Binary C Coding D Os and 1s

199 Slide 129 (Answer) / The language of computers that works using zeros and ones is called. A Morse Code B Binary C Coding D Os and 1s Answer B [This object is a pull tab]

200 Slide 130 / Cellphones use waves to communicate. True False

201 Slide 130 (Answer) / Cellphones use waves to communicate. True False Answer TRUE [This object is a pull tab]

202 Slide 131 / 131 Binary Code Lab Teacher Notes