How much energy is in my wave?
Learning Objectives
· Identify how to measure a wavelength, (from crest to crest).
· Describe the relationship between wavelength, velocity, and energy.
· Make connections between the visible light spectrum activity and their new knowledge of wave properties.
· Identify parts of a wave and be able to explain it to a classmate.
· Major vocabulary: wavelength, velocity, energy, crest, trough, amplitude, height, mid-line.
Assessment Criteria
· Using their observational drawings of the demo wave, the students will be discussing the measurement of a wavelength, as well as the relationship between wavelength, velocity, and energy.
· Their discussion question handout makes the connections between the previous visible light spectrum lesson, as well as their homework assignment of drawing a red and purple wave with appropriate scale and labels.
· During the wrap-up, the students discuss with a partner their observational notes and then share with the class the similarities/differences between the two partners’ notes, using the new vocabulary.
Standards/Benchmarks:
National Science Education Standards
The sun is a major source of energy for changes on the earth's surface. The sun loses energy by emitting light. A tiny fraction of that light reaches the earth, transferring energy from the sun to the earth. The sun's energy arrives as light with a range of wavelengths, consisting of visible light, infrared, and ultraviolet radiation. 8BPS3.6
AAAS Benchmarks for Science Literacy
Human eyes respond to only a narrow range of wavelengths of electromagnetic waves-visible light. Differences of wavelength within that range are perceived as differences of color. 4F/M5
Relationship to the driving question: This lesson demonstrates and defines what a wave is and it’s properties, using various modeling activities. This would serve as a link between the prism activity, when students are introduced to visible as waves, and subsequent lessons that focus on different types of electromagnetic waves that students interact with on a daily basis.
Prior Knowledge/Prior Conceptions: Students will know that visible light acts as a wave, but they won’t really know how to define that term yet. Students might have a concept that waves are stagnant, that they do not move, and that there is only one type that exists in nature.
Instructional strategies: This lesson will include a teacher, and eventually student, led demonstration showing how waves move and can increase/decrease in frequency. It will also use a concept map for students to generate their own ideas about a “Wave” and provide an assessment using a diagram of a wave as well as some small group discussion questions.
Instructional resources used: The standing wave demonstration activity is adapted from: http://www.ucar.edu/learn/1_5_2_22t.htm
Materials and set-up needed:
Materials:
Electric drill
Chuck key
20-penny bent nail
#2 barrel swivels (found in fishing section of sporting goods stores)
1/8” nylon cord 1 ft long
1/8” nylon cord 12-15 ft long
15 ft long rope (optional)
Slinky (optional)
Plain paper
Markers/Colored Pencils
Wave handout with diagram
Set Up:
Image from: http://www.ucar.edu/learn/1_5_2_22t.htm
Bend 20-penny nail as shown (use a vise to accomplish this)
Attach a swivel to each end of the nylon cord.
Tie the 1-foot piece of cord to one of the swivel holders. This is the piece of cord that a student will hold during the demonstration.
Slide the bent nail through the eye of the other swivel.
The nail end should be put into the drill bit fitting and tightened securely with the chuck key.
The longer nylon cord is then attached to the 1 foot piece of cord and electric drill; this is what is creating the wave during the demo.
Time required: ~45 minutes.
Cautions: Make sure to test the demonstration before showing the students, as this could be dangerous if not set up properly. If the students are not mature enough to handle the drill activity, they should not be allowed to participate.
Teacher Note: If safety and practicality of this experiment is of concern, students can generate a wave using a long piece of rope. By having two students at either end of the rope, they can use hold on to the ends and use their arms to create different wavelengths.
Instructional sequence:
Introducing the lesson:
Remind students of the prism activity where they investigate the visible light spectrum. Ask the students:
· What did you learn about visible colors? Any response is good-just to get students warmed up about previous lesson.
· What colors make up white light? ROYGBIV
· What was the unit that we measured the light in? wavelength
Now, lead students into an activity to get them thinking about waves. Ask students:
· What is a wave?
· Where have you heard that word before?
Allow students to generate responses to these questions. Then, explain that the students will pair up and make a concept map of what they know about the word “wave”. Pass out plain paper and markers/colored pencils.
Teacher Note: For this activity, it is best to pair up students of differing abilities, i.e. a high performing and low or mid performing student. This will ensure that the concept maps are equitable across the class and not showcasing the high performing students’ exceptional abilities compared to the low performing students’ maps.
After students have completed the maps, either post them in the room for students to refer back to or, have them paste it in their science notebooks.
Body of the lesson:
Now, say to the class that they will begin talking about electromagnetic waves and how they are all around us in nature and society, i.e. harnessed by man for different purposes. First, however, the students will investigate and discuss what a wave actually is, i.e. define it, and the different parts of the wave.
In their science notebooks, encourage the students to draw what they see and describe what is happening during the demonstration (similar to taking observation notes of a science experiment!) Begin the demonstration of the electric drill generated wave. One student can hold the 1 ft long nylon cord while the teacher holds the drill. By adjusting the speed on the drill, the waves will become different sizes and act in different ways. Ask the students:
· In this demo, what is a wavelength? Have students come up with some ideas, orally. Then, explain that one wavelength measures from crest to crest.
· What happens when the velocity (speed) of the wave slows down? Speeds up? The wavelength will increase as the speed decreases, decrease when speed increases.
· How could we use the word energy to describe the increase and decrease of the wavelength? Does a small wavelength have more or less energy than a larger wavelength? Waves have more energy in them when they are moving fast, i.e. are smaller.
Teacher Note: Based on the instructor’s modifications, these same exercises can be performed using the rope: by adjusting the speed of the demonstrators arms, the wave crest lengths can be adjusted and wavelength velocity and energy can be discussed.
If desired, allow students to adjust the drill themselves or suggest different ways to manipulate the drill, and thus the types of waves created.
Show an example of a wave diagrams on the powerpoint slide. Ask students to identify some of the differences between the two pictures. One mentions sea level while the other mentions distance/time. Sea level can also be called the midline.
With their drawing of their wave from the demo, have the students label the waves they made with the new vocabulary they have just acquired: crest, trough, wavelength, amplitude, midline, and height.
In small groups, have the students connect their ideas from the visible light spectrum lesson to this one. Pass out a handout that lists discussion questions:
· Which color, red or purple, has a faster velocity? Which one has more energy?
· A certain wave has a speed of 300 nm/sec. Another wave has a speed of 900 nm/sec. Which wave has more energy? Which wave has a longer wavelength?
· A certain wave has a wavelength of 1200 nm. Another wave has a wavelength of 500 nm. Which wavelength has a faster velocity? Which one has more energy?
· Describe the relationship between wavelength, velocity, and energy. What is a good way to remember this relationship?
· Ultraviolet (UV) light is known to be dangerous to humans, causing not just sunburns but skin cancer. Ultraviolet light is ULTRA shorter than violet light, i.e. the wavelength is smaller than violet light. Knowing what you know about the relationship between wavelengths and energy, what is one reason that UV light is so dangerous? What does this say about waves that are even smaller than UV light, such as microwaves, X-rays, and gamma rays?
In addition to these discussion questions, the students will also be assigned to draw a red and purple wave, using the measurements from their prism activity, to accurately depict the size of the wavelength.
· Red is ~650-700 nm while purple is ~400-425 nm. So, using cm, the students can draw from crest to crest a red wavelength of 6.5 or 7 cm while the purple wave would be 4-4.25 cm.
· Make sure to model this using other wavelengths if students are unclear on the task.
· They should also label the parts of their red and purple waves with the vocabulary they have learned in this lesson.
· This can be assigned as homework or completed in class if there is time.
For homework, the students should finish their discussion questions and their wave drawing assignment.
Wrapping up the lesson: As the students work on their discussion questions, review the first two learning objectives of the lesson. (The third learning objective can be addressed the next day once students have completed their discussion questions and their assessment.) Ask the students to share with their partner their drawings of the demo wave and describe to their partner what they saw and what they labeled. They should also talk about the similarities/differences in their drawings. Then, some groups can share with the rest of the class what they talked about in their groups, i.e. what they saw and what they labeled.
Evaluating learning: Throughout the lesson, I guide the students with discussion questions to think about the concepts they are witnessing in the classroom and in the real world. The written and sketched assessments serve to allow students to express themselves and think about what they are seeing and how they can describe the phenomena.
Their discussion questions directly answer the driving question, as students come up with a relationship between wave and energy.
Design Rationale: In class we discuss using real demonstrations to show a scientific concept instead of just telling students about something. Here, I also wanted to incorporate a previous lesson on prisms and the visible light spectrum so, I based the discussion questions on integrating both lessons as well as touching on the broader implications of wave energy in UV light. It was important to me for the students to express their own ideas about waves, and to come up with ways to help themselves remember the main relationships between wavelength, energy, and velocity. Also, by drawing and discussing the parts of a wave, hopefully this will give the students more opportunities to use their new vocabulary and get more comfortable with it.
Learning Objectives
· Identify how to measure a wavelength, (from crest to crest).
· Describe the relationship between wavelength, velocity, and energy.
· Make connections between the visible light spectrum activity and their new knowledge of wave properties.
· Identify parts of a wave and be able to explain it to a classmate.
· Major vocabulary: wavelength, velocity, energy, crest, trough, amplitude, height, mid-line.
Assessment Criteria
· Using their observational drawings of the demo wave, the students will be discussing the measurement of a wavelength, as well as the relationship between wavelength, velocity, and energy.
· Their discussion question handout makes the connections between the previous visible light spectrum lesson, as well as their homework assignment of drawing a red and purple wave with appropriate scale and labels.
· During the wrap-up, the students discuss with a partner their observational notes and then share with the class the similarities/differences between the two partners’ notes, using the new vocabulary.
Standards/Benchmarks:
National Science Education Standards
The sun is a major source of energy for changes on the earth's surface. The sun loses energy by emitting light. A tiny fraction of that light reaches the earth, transferring energy from the sun to the earth. The sun's energy arrives as light with a range of wavelengths, consisting of visible light, infrared, and ultraviolet radiation. 8BPS3.6
AAAS Benchmarks for Science Literacy
Human eyes respond to only a narrow range of wavelengths of electromagnetic waves-visible light. Differences of wavelength within that range are perceived as differences of color. 4F/M5
Relationship to the driving question: This lesson demonstrates and defines what a wave is and it’s properties, using various modeling activities. This would serve as a link between the prism activity, when students are introduced to visible as waves, and subsequent lessons that focus on different types of electromagnetic waves that students interact with on a daily basis.
Prior Knowledge/Prior Conceptions: Students will know that visible light acts as a wave, but they won’t really know how to define that term yet. Students might have a concept that waves are stagnant, that they do not move, and that there is only one type that exists in nature.
Instructional strategies: This lesson will include a teacher, and eventually student, led demonstration showing how waves move and can increase/decrease in frequency. It will also use a concept map for students to generate their own ideas about a “Wave” and provide an assessment using a diagram of a wave as well as some small group discussion questions.
Instructional resources used: The standing wave demonstration activity is adapted from: http://www.ucar.edu/learn/1_5_2_22t.htm
Materials and set-up needed:
Materials:
Electric drill
Chuck key
20-penny bent nail
#2 barrel swivels (found in fishing section of sporting goods stores)
1/8” nylon cord 1 ft long
1/8” nylon cord 12-15 ft long
15 ft long rope (optional)
Slinky (optional)
Plain paper
Markers/Colored Pencils
Wave handout with diagram
Set Up:
Image from: http://www.ucar.edu/learn/1_5_2_22t.htm
Bend 20-penny nail as shown (use a vise to accomplish this)
Attach a swivel to each end of the nylon cord.
Tie the 1-foot piece of cord to one of the swivel holders. This is the piece of cord that a student will hold during the demonstration.
Slide the bent nail through the eye of the other swivel.
The nail end should be put into the drill bit fitting and tightened securely with the chuck key.
The longer nylon cord is then attached to the 1 foot piece of cord and electric drill; this is what is creating the wave during the demo.
Time required: ~45 minutes.
Cautions: Make sure to test the demonstration before showing the students, as this could be dangerous if not set up properly. If the students are not mature enough to handle the drill activity, they should not be allowed to participate.
Teacher Note: If safety and practicality of this experiment is of concern, students can generate a wave using a long piece of rope. By having two students at either end of the rope, they can use hold on to the ends and use their arms to create different wavelengths.
Instructional sequence:
Introducing the lesson:
Remind students of the prism activity where they investigate the visible light spectrum. Ask the students:
· What did you learn about visible colors? Any response is good-just to get students warmed up about previous lesson.
· What colors make up white light? ROYGBIV
· What was the unit that we measured the light in? wavelength
Now, lead students into an activity to get them thinking about waves. Ask students:
· What is a wave?
· Where have you heard that word before?
Allow students to generate responses to these questions. Then, explain that the students will pair up and make a concept map of what they know about the word “wave”. Pass out plain paper and markers/colored pencils.
Teacher Note: For this activity, it is best to pair up students of differing abilities, i.e. a high performing and low or mid performing student. This will ensure that the concept maps are equitable across the class and not showcasing the high performing students’ exceptional abilities compared to the low performing students’ maps.
After students have completed the maps, either post them in the room for students to refer back to or, have them paste it in their science notebooks.
Body of the lesson:
Now, say to the class that they will begin talking about electromagnetic waves and how they are all around us in nature and society, i.e. harnessed by man for different purposes. First, however, the students will investigate and discuss what a wave actually is, i.e. define it, and the different parts of the wave.
In their science notebooks, encourage the students to draw what they see and describe what is happening during the demonstration (similar to taking observation notes of a science experiment!) Begin the demonstration of the electric drill generated wave. One student can hold the 1 ft long nylon cord while the teacher holds the drill. By adjusting the speed on the drill, the waves will become different sizes and act in different ways. Ask the students:
· In this demo, what is a wavelength? Have students come up with some ideas, orally. Then, explain that one wavelength measures from crest to crest.
· What happens when the velocity (speed) of the wave slows down? Speeds up? The wavelength will increase as the speed decreases, decrease when speed increases.
· How could we use the word energy to describe the increase and decrease of the wavelength? Does a small wavelength have more or less energy than a larger wavelength? Waves have more energy in them when they are moving fast, i.e. are smaller.
Teacher Note: Based on the instructor’s modifications, these same exercises can be performed using the rope: by adjusting the speed of the demonstrators arms, the wave crest lengths can be adjusted and wavelength velocity and energy can be discussed.
If desired, allow students to adjust the drill themselves or suggest different ways to manipulate the drill, and thus the types of waves created.
Show an example of a wave diagrams on the powerpoint slide. Ask students to identify some of the differences between the two pictures. One mentions sea level while the other mentions distance/time. Sea level can also be called the midline.
With their drawing of their wave from the demo, have the students label the waves they made with the new vocabulary they have just acquired: crest, trough, wavelength, amplitude, midline, and height.
In small groups, have the students connect their ideas from the visible light spectrum lesson to this one. Pass out a handout that lists discussion questions:
· Which color, red or purple, has a faster velocity? Which one has more energy?
· A certain wave has a speed of 300 nm/sec. Another wave has a speed of 900 nm/sec. Which wave has more energy? Which wave has a longer wavelength?
· A certain wave has a wavelength of 1200 nm. Another wave has a wavelength of 500 nm. Which wavelength has a faster velocity? Which one has more energy?
· Describe the relationship between wavelength, velocity, and energy. What is a good way to remember this relationship?
· Ultraviolet (UV) light is known to be dangerous to humans, causing not just sunburns but skin cancer. Ultraviolet light is ULTRA shorter than violet light, i.e. the wavelength is smaller than violet light. Knowing what you know about the relationship between wavelengths and energy, what is one reason that UV light is so dangerous? What does this say about waves that are even smaller than UV light, such as microwaves, X-rays, and gamma rays?
In addition to these discussion questions, the students will also be assigned to draw a red and purple wave, using the measurements from their prism activity, to accurately depict the size of the wavelength.
· Red is ~650-700 nm while purple is ~400-425 nm. So, using cm, the students can draw from crest to crest a red wavelength of 6.5 or 7 cm while the purple wave would be 4-4.25 cm.
· Make sure to model this using other wavelengths if students are unclear on the task.
· They should also label the parts of their red and purple waves with the vocabulary they have learned in this lesson.
· This can be assigned as homework or completed in class if there is time.
For homework, the students should finish their discussion questions and their wave drawing assignment.
Wrapping up the lesson: As the students work on their discussion questions, review the first two learning objectives of the lesson. (The third learning objective can be addressed the next day once students have completed their discussion questions and their assessment.) Ask the students to share with their partner their drawings of the demo wave and describe to their partner what they saw and what they labeled. They should also talk about the similarities/differences in their drawings. Then, some groups can share with the rest of the class what they talked about in their groups, i.e. what they saw and what they labeled.
Evaluating learning: Throughout the lesson, I guide the students with discussion questions to think about the concepts they are witnessing in the classroom and in the real world. The written and sketched assessments serve to allow students to express themselves and think about what they are seeing and how they can describe the phenomena.
Their discussion questions directly answer the driving question, as students come up with a relationship between wave and energy.
Design Rationale: In class we discuss using real demonstrations to show a scientific concept instead of just telling students about something. Here, I also wanted to incorporate a previous lesson on prisms and the visible light spectrum so, I based the discussion questions on integrating both lessons as well as touching on the broader implications of wave energy in UV light. It was important to me for the students to express their own ideas about waves, and to come up with ways to help themselves remember the main relationships between wavelength, energy, and velocity. Also, by drawing and discussing the parts of a wave, hopefully this will give the students more opportunities to use their new vocabulary and get more comfortable with it.