Goals
1. describe what causes beats
2. draw and label the first three harmonic wave patterns
3. solve wave harmonics problems
4. understand patterns in the wavelength and frequency of harmonics
Warm-Up
Review Beat Frequency with Bo: https://www.flippingphysics.com/beat-frequency.html
1. What causes beats?
2. After watching the 4min video, what is a practical application of beats?
3. Give two examples of stringed instruments
4. Give two examples of wind instruments (look this up on the interwebs if you need to)
Classwork:
Slideshow on harmonic frequencies on stringed and wind instruments: https://docs.google.com/presentation/d/1PoTkxptRu-EVcQB66zmZs7fE-uEk9y0yj8hZY-SsFoo/edit?usp=sharing
ESSENTIAL QUESTION: What are the characteristics of EM waves?
Goals:
SWBAT
1. combine colors to remove (absorb) unwanted colors
2. solve color subtraction problems via algebra equations
WARM-UP (3min)
write a sentence explaining how the combination of the indigo and orange filters creates red light.
Hint: You can use the phet RGB color simulator from yesterday to answer the above question LINK
CLASSWORK
All that is below is on the Schoology assignment. Go to Schoology Materials, open the assignment, do the assignment, and submit via Schoology
151A: Color Subtraction
To create colors, printers and artists use three main colors of paint to remove (absorb) unwanted colors.
Consider a cyan filter - which colors does it allow to pass? Which color will it absorb?
Example 1:
Example 2: Magenta light shines on a sheet of paper containing a yellow pigment. Determine the appearance of the paper.
Example 3: Yellow light shines on a sheet of paper containing a red pigment. Determine the appearance of the paper.
Example 4: Yellow light shines on a sheet of paper containing a blue pigment. Determine the appearance of the paper.
151B: Primary Colors of Paint
A trip to the local newspaper or film developing company will reveal these same principles of color subtraction at work. The three primary colors of paint used by an artist, color printer or film developer are cyan (C), magenta (M), and yellow (Y)
Each primary color of paint absorbs one primary color of light. The color absorbed by a primary color of paint is the complementary color of that paint. The three colors that are primary to an artist (magenta, cyan, and yellow) subtract red, green, and blue individually from an otherwise white sheet of paper. Thus,
Magenta paints absorb green light.
Cyan paints absorb red light.
Yellow paints absorb blue light.
Let's suppose that an artist wishes to use the three primary colors of paint in order to produce a picture of the colorful bird shown at the right. The bird will be painted onto white paper and viewed under white light. It is hoped that the bird will have green tail feathers, a blue lower body, a cyan upper body, a red head, a magenta eye patch, a yellow eye and middle feathers, and a black beak. How can the three primary colors of paint be used to produce such a likeness? And how can we explain the answers in terms of color subtraction?
green tail feathers, Example: apply C & Y
a blue lower body, apply _______ M & C
a cyan upper body, apply ______ C
a red head, ________ M & Y
a magenta eye patch, _______ M
a yellow eye and middle feathers, ________ Y
and a black beak, ________ ALLLLLLLLLLLLL
151C: Applications of Color Subtraction:
Activity: LINK
HOMEWORK
If you didn't complete today's classwork, complete it by 11:59pm tonight, and submit it via Schoology. It will be late, and you will lose some credit, however partial credit is better than no credit.
Unable to access today's CW assignment? Here's the link:
151A,B: https://docs.google.com/document/d/1Zaa934NwL9argye68qr-DRv6n52ACqx3Z3fJqdaDU-8/edit?usp=sharing
151C: https://docs.google.com/document/d/1-F_Ra4whg80iG6zSlvQdnbLH40H55ZWTMQkAFeXWWsg/edit?usp=sharing