DAY 150

Today's video lecture --> https://youtu.be/ajc7mGcq_jQ

Later today I'll attempt to have my kids find constructive and destructive interference in our living room. Video of that will go here --->

Zoom from 11:00-11:30 today and Thursday. Details on Schoology and via Remind at 9:30am today.

GOALS SWBAT...

1. identify properties of the sound waves from musical instruments by utilizing the principals of wave interactions

2. define “Beats” as they relate to interference

3. analyze a spectrograph to determine if a sound is composed mainly of one frequency, or a combination of frequencies

WARM-UP

1. Copy the three sets of images. Use different colors, or a pen and a pencil, or different darkness lines. For each scenario, the red pulse and blue pulse interfere to form the green pulse. Decide if the two pulses create constructive or destructive interference, and label the image as "constructive" or "destructive".

CLASSWORK

Your classwork for today is all contained in this slideshow --> link

ESSENTIAL QUESTION: What are the characteristics of EM waves?

Goal:

SWBAT write a sentence explaining how the combination of the indigo and orange filters creates red light.

WARM-UP (4min)

Color perception, like sound perception, is a complex subject involving the disciplines of psychology, physiology, biology, chemistry and physics. When you look at an object and perceive a distinct color, you are not necessarily seeing a single frequency of light.

1. When you see indigo, which two colors are being combined to create that color?

2. When you see orange, which two colors are being combined to create that color?

Hint: You can use the phet RGB color simulator from yesterday to create those colors, and answer the above questions LINK

CLASSWORK

Review from yesterday:

Color Addition Rules

These demonstrations with the color box illustrate that red light and green light add together to produce yellow (Y) light. Red light and blue light add together to produce magenta (M) light. Green light and blue light add together to produce cyan (C) light. And finally, red light and green light and blue light add together to produce white light. This is sometimes demonstrated by the following color equations and graphic:

R + G = Y

R + B = M

G + B = C

150A: Reading/Notes "Where Does Color Come From?"

This assignment is on Schoology. Find your copy there, edit it, and submit it. Should take approximately 15 minutes. This is due approx 30 minutes after class starts, so work efficiently.

The color of the objects that we see is largely due to the way those objects interact with light and ultimately reflect or transmit it to our eyes.
The color of an object is not actually within the object itself. The color is in the light that shines upon it and is ultimately reflected or transmitted to our eyes.
Visible light spectrum consists of a range of frequencies, each of which corresponds to a specific color.
When visible light strikes an object and a specific frequency becomes absorbed, that frequency of light will never make it to our eyes.
Any visible light that strikes the object and becomes reflected or transmitted to our eyes will contribute to the color appearance of that object.
So the color is not in the object itself, but in the light that strikes the object and ultimately reaches our eye.
The only role that the object plays is that it might contain atoms capable of selectively absorbing one or more frequencies of the visible light that shine upon it.
So if an object absorbs all of the frequencies of visible light except for the frequency associated with green light, then the object will appear green in the presence of ROYGBIV.
And if an object absorbs all of the frequencies of visible light except for the frequency associated with blue light, then the object will appear blue in the presence of ROYGBIV.
Consider the two diagrams below. The diagrams depict a sheet of paper being illuminated with white light (ROYGBIV). The papers are impregnated with a chemical capable of absorbing one or more of the colors of white light. Such chemicals that are capable of selectively absorbing one or more frequency of white light are known as pigments. In Example A, the pigment in the sheet of paper is capable of absorbing red, orange, yellow, blue, indigo and violet. In Example B, the pigment in the sheet of paper is capable of absorbing orange, yellow, green, blue, indigo and violet. In each case, whatever color is not absorbed is reflected.

1. Check your understanding of these principles by determining which color(s) of light are reflected by the paper and what color the paper will appear to an observer.

What about TRANSPARENT materials?

Transparent materials are materials that allow one or more of the frequencies of visible light to be transmitted through them; whatever color(s) is/are not transmitted by such objects, are typically absorbed by them. The appearance of a transparent object is dependent upon what color(s) of light is/are incident upon the object and what color(s) of light is/are transmitted through the object.

2. Express your understanding of this principle by filling in the blanks in the following diagrams.

3. The diagrams depict a sheet of paper being illuminated with white light (ROYGBIV). The papers are impregnated with a chemical capable of absorbing one or more of the colors of white light. In each case, determine which color(s) of light are reflected by the paper and what color the paper will appear to an observer.

4. The appearance of a transparent object is dependent upon which color(s) of light is/are incident upon the object and which color(s) of light is/are transmitted through the object. Express your understanding of this principle by determining which color(s) of light will be transmitted and the color that the paper will appear to an observer.

150B: Color Filters Simulator

Key Question: how can you combine two or more filters to create a specific color? (example: how could orange and indigo filters transmit red light?). This assignment is on Schoology. Find your copy there, edit it, and submit it. Should take approximately 30 minutes. This is due tonight by 11:59pm.

Interactive: LINK

HOMEWORK

Complete 150B due on time by 11:59pm tonight.

also, write a sentence explaining how the combination of the indigo and orange filters creates red light.

If you didn't complete today's 150A 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 links:

150A: LINK

150B: LINK