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2015 MCAS Physics Exam

#4. The graph below shows how the temperature of a sample of water changes as energy is added to the sample.

heating-of-water-curve

During which interval does a gas form?
A. Q to R
B. R to S
C. S to T
D. T to U

_ _ _ _ _ _ _ _ _ _ _ _ _ _

#21. Sunlight warms an area of Earth’s surface. Winds then carry thermal energy from this area to another location. Which two heat transfer processes are primarily involved in this situation?

A. radiation and convection
B. radiation and evaporation
C. conduction and convection
D. conduction and evaporation

_ _ _ _ _ _ _ _ _ _ _ _ _ _

#24. Frozen food is submerged in a small insulated container of 95°C water. Which statement best describes the temperature of the food after two hours, assuming no heat is lost outside of the insulated container?

A. The temperature of the food will be 95°C.
B. The temperature of the food will be 100°C.
C. The temperature of the food will be the same as the temperature of the water.
D. The temperature of the food will be greater than the temperature of the water.

_ _ _ _ _ _ _ _ _ _ _ _ _ _

#31 A student heats 200 g of water from 20°C to 70°C. How much heat did the student add to the water if the specific heat for water is 4.2 J/g C •° ?

A. 10,000 J B. 14,000 J

C. 42,000 J D. 76,000 J

_ _ _ _ _ _ _ _ _ _ _ _ _ _

#44 A student was investigating cooling times for two pots made of different materials. One pot was stainless steel and the other pot was iron. The pots were placed on a table in a 25°C room. The pots were roughly the same size and shape, and contained the same amount of water. The pots and water were originally at 100°C. The student recorded the temperature of the water in each pot over time. The graph below shows the results.

stainless-steel-iron-heating

a. Determine the amount of time it took the water in the iron pot to cool from 100°C to 60°C.

b. Based on the graph, which pot, the iron pot or the stainless steel pot, was a better conductor of thermal energy? Explain your answer.

c. Identify two methods of heat transfer that occurred as the water in the pots cooled, and describe how the transfer of heat occurred for each method.

d. Describe when the pots no longer experienced a net loss of thermal energy.

2016 MCAS Physics Exam

A 1 kg sample of liquid water and a 1 kg sample of ice are placed on a table. Which of the following statements best compares these two samples?

A. The liquid water has a larger volume than the ice.
B. The liquid water has a greater weight than the ice.
C. The liquid water has more thermal energy than the ice.
D. The liquid water has more gravitational potential energy than the ice.

_ _ _ _ _ _ _ _ _ _ _ _ _ _

6. Two U.S. quarters, initially at the same temperature, are heated with a flame. One of the quarters was made before 1965 and is composed of silver. The
other quarter was made after 1965 and is composed mostly of copper.
What information is needed to determine which quarter will heat up faster?

A. the specific heats of the metals and the mass of each coin
B. the initial temperature of the coins and the mass of each coin
C. the temperature of the flame and the specific heats of the metals
D. the initial temperature of the coins and the temperature of the flame

_ _ _ _ _ _ _ _ _ _ _ _ _ _

16. A fan enables a computer’s processor to run for long periods of time without overheating. Which of the following forms of heat energy transfer does this
example best represent?

A. condensation
B. convection
C. evaporation
D. radiation

_ _ _ _ _ _ _ _ _ _ _ _ _ _

18. A small steel rod is placed in 5 L of water. The initial temperature of the steel rod is 120°C, and the initial temperature of the water is 10°C. When does heat stop flowing between the steel rod and the water?

A. when the steel rod reaches 65°C
B. when the water reaches its boiling point
C. when the steel rod reaches 10°C and the water reaches 120°C
D. when the steel rod and the water reach the same temperature

_ _ _ _ _ _ _ _ _ _ _ _ _ _

27. Two identical objects, one hot and one cold, are placed near each other in a closed system. Which of the following graphs shows what happens to the temperatures of the objects over time?

_ _ _ _ _ _ _ _ _ _ _ _ _ _

44. During cold periods, many orange growers repeatedly spray their trees with water to prevent the oranges from freezing. If the air is cold enough, the sprayed water freezes around the oranges, leaving the oranges themselves unfrozen.

a. Identify a measurement tool that orange growers use to measure the average kinetic energy of the air.
b. Describe what happens to the average molecular kinetic energy of the sprayed water
as it cools before it freezes.
c. Describe what happens to the average molecular kinetic energy of the sprayed water
as it freezes.
d. Explain how the phase change of the sprayed water may protect the oranges from freezing.

_ _ _ _ _ _ _ _ _ _ _ _ _ _

Sample “Open Response” answers: Question 44: Open-Response

Question 44: Open-Response
Reporting Category: Heat and Heat Transfer
Standard: 3.1 – Explain how heat energy is transferred by convection, conduction, and radiation.

A student was investigating cooling times for two pots made of different materials. One pot was stainless steel and the other pot was iron. The pots were placed on a table in a 25°C room. The pots were roughly the same size and shape, and contained the same amount of water. The pots and water were originally at 100°C. The student recorded the temperature of the water in each pot over time. The graph below shows the results.

stainless-steel-iron-heating

a. Determine the amount of time it took the water in the iron pot to cool from 100°C to 60°C.

b. Based on the graph, which pot, the iron pot or the stainless steel pot, was a better conductor of thermal energy? Explain your answer.

c. Identify two methods of heat transfer that occurred as the water in the pots cooled, and describe how the transfer of heat occurred for each method.

d. Describe when the pots no longer experienced a net loss of thermal energy.

Scoring Guide and Sample Student Work
Select a score point in the table below to view the sample student response.

Score	Description
4	The response demonstrates a thorough understanding of heat transfer by convection, conduction, and radiation and of thermal equilibrium. The response correctly determines the time it took for water in the iron pot to cool to 60°C, and clearly explains which pot is a better conductor. The response also correctly identifies and clearly describes two methods of heat transfer that occurred as the water cooled, and describes when the pots no longer experienced a net loss of thermal energy.
4
3	The response demonstrates a general understanding of heat transfer by convection, conduction, and radiation and of thermal equilibrium.
2	The response demonstrates a limited understanding of heat transfer by convection, conduction, and radiation and of thermal equilibrium.
1	The response demonstrates a minimal understanding of heat transfer by convection, conduction, and radiation and of thermal equilibrium.
0	The response is incorrect or contains some correct work that is irrelevant to the skill or concept being measured.

Note: There are 2 sample student responses for Score Point 4.

MCAS wave problems

January 17, 2017 5:15 pm

MCAS Physics exam: Example Problems

MCAS 2011

Which of the following describes and explains what the observer hears as the buzzer moves away from him?

A. a lower-pitched buzz than the buzzer’s normal sound because the sound waves are arriving less frequently
B. a higher-pitched buzz than the buzzer’s normal sound because the sound waves are arriving more frequently
C. a lower-pitched buzz than the buzzer’s normal sound because the velocity of the sound waves is reduced by the velocity of the swinging buzzer
D. a higher-pitched buzz than the buzzer’s normal sound because the velocity of the sound waves is increased by the velocity of the swinging buzzer

#25, MCAS 2011

longitudinal air wave in tube MCAS 2011.PNG

#32. Essay question, MCAS 2011

A large anchor is being lifted into a boat with metal sides. As the anchor leaves the water it
hits the side of the boat, making loud sounds and making waves on the surface of the water.

a. Describe the motions of the sound waves and the water waves.
b. Draw a diagram for each of the waves you described in part (a). Be sure to label each
diagram.
c. Describe how the wavelength is measured for the water waves

#35. Which of the following observations demonstrates that visible light waves are
electromagnetic and not mechanical?

A. Sunlight can pass through gas.
B. Sunlight can pass through solids.
C. Sunlight can pass through liquids.
D. Sunlight can pass through a vacuum.

#37, MCAS 2011
Which of the following statements best explains why lightning is seen before thunder is heard?

A. Electromagnetic waves travel faster than mechanical waves in air.
B. Electromagnetic waves have a higher frequency than mechanical waves.
C. Electromagnetic waves experience less interference than mechanical waves.
D. Electromagnetic waves form faster than mechanical waves during a thunderstorm.

#3, MCAS 2011
In a large room, a sound wave traveling from a violin produces a tone with a frequency of 264 Hz. The speed of sound in the room is 340 m/s. What is the wavelength of the sound wave from the violin?

A. 0.004 m B. 0.80 m C. 1.3 m D. 2.6 m

MCAS 2012

2. When music plays through the speaker, the speaker rapidly moves back and forth in the cabinet. Which of the following conclusions is best supported by this observation?

A. Sound travels only in air.
B. Sound is a transverse wave.
C. Sound is a longitudinal wave.
D. Sound travels at the speed of light

4. Which of the following statements best describes a difference between mechanical waves and electromagnetic waves?
A. Mechanical waves can produce colored light, while electromagnetic waves cannot.
B. Mechanical waves can travel in any direction, while electromagnetic waves travel only in one direction.
C. Mechanical waves travel only through a medium, while EM waves can also travel through a vacuum.
D. Mechanical waves travel only at the speed of light, while electromagnetic waves can travel at many different speeds.

6. A student is sitting on the edge of a swimming pool. The student repeatedly dips his foot in and out of the pool, making waves that move across the water. The student dips his foot slowly at first and then does it faster, each time to the same depth. Which of the following properties of the waves increases as the student dips his foot faster?

A. frequency
B. period
C. velocity
D. wavelength

21. A rope is stretched horizontally between two students. One of the students shakes an end of the rope up and down. Which of the following terms best describes the type of wave that is produced?

A. electromagnetic
B. longitudinal
C. rotational
D. transverse

#26. MCAS 2012

mcas-2012-represent-an-em-wave

#29. Student X and student Y are receiving sound waves from a stationary source. The sound waves have a frequency of 10 kHz. Student X is stationary and student Y is traveling toward the source of the sound waves.
Which of the following statements describes what will happen as student Y moves?

A. Student X will receive sound waves with a frequency higher than 10 kHz.B. Student X will receive sound waves with a frequency lower than 10 kHz.
C. Student Y will receive sound waves with a frequency higher than 10 kHz.
D. Student Y will receive sound waves with a frequency lower than 10 kHz.

#37 Two waves traveling in the same medium are shown below.

mcas-2012-comparing-waves

Which of the following correctly compares the two waves?
A. Wave X has half the amplitude of wave Y.
B. Wave X has twice the amplitude of wave Y.
C. Wave X has a lower frequency and longer wavelength than wave Y.
D. Wave X has a higher frequency and shorter wavelength than wave Y

#42 In which of the following media do sound waves most likely travel the fastest?
A. crude oil
B. distilled water
C. solid steel
D. warm air

MCAS 2013

#2. A student is shaking one end of a small rug with a ball on top of it. The wave that is produced travels through the rug and moves the ball upward, as shown in the diagram below

shake-rug-waves-mcas-2013

#6. A person is driving north in a car at a constant speed. A police officer is
driving south toward him at a constant speed. The police officer uses a radar
unit to measure the speed of the person’s car. The radar unit sends out waves of
a certain frequency toward the person’s car. The waves reflect off the person’s car and travel back to the radar unit in the police car. What happens to the frequency of the waves detected by the radar unit?
A. The frequency is lower as the person’s car approaches.
B. The frequency is higher as the person’s car approaches.
C. The frequency remains the same but with increased energy as the person’s car approaches.
D. The frequency remains the same but with decreased energy as the person’s car approaches.

#22. Which of the following properties makes a light wave different from all mechanical waves?
A. A light wave slows down in a vacuum.
B. A light wave is able to transmit energy.
C. A light wave exists as a transverse wave.
D. A light wave can travel without a medium

#25. Which of the following observed properties of a wave is changed by the Doppler effect?
A. amplitude
B. direction
C. frequency
D. speed

#28. The diagram below shows two students making a wave with a coiled spring

mcas-2103-spring-waves-on-tabletop

MCAS 2014

#2. Waves rock a boat in the middle of a pond. The boat moves up and down 10 times in 20 seconds. What is the period of the waves?
A. 0.5 s B. 2 s C. 10 s D. 20 s

#16. A sound wave with a frequency of 1,700 Hz is traveling through air at a speed of 340 m/s. What is the wavelength of this sound wave?
A. 0.2 m B. 5.0 m C. 2,040 m D. 57,800 m

#19. Sunscreen protects skin by absorbing harmful ultraviolet radiation from the Sun. Ultraviolet radiation has which of the following properties?
A. a shorter wavelength than x-rays
B. a lower frequency than radio waves
C. a higher frequency than visible light
D. a longer wavelength than microwaves

#23. ESSAY. Waves can be classified as either electromagnetic or mechanical.
a. Describe two differences between electromagnetic and mechanical waves.
b. Give two examples of electromagnetic waves.
c. Give two examples of mechanical waves.

#26. A wave with a wavelength of 3.2 m is generated in a pond. The frequency of the wave is 0.60 Hz. What is the speed of this wave?
A. 0.19 m/s
B. 1.9 m/s
C. 3.8 m/s
D. 5.3 m/s

#30. The diagram below shows a representation of two different waves

2-spring-waves-transverse-longitudinal-mcas-2014

MCAS 2015

14. A train driver blows the train’s horn as it moves away from a station. Which of the following statements describes how the sound of the horn heard by an observer standing at the station platform differs from the sound heard by the train driver?
A. The observer hears the sound as having a greater velocity.
B. The observer hears the sound as having a lower frequency.
C. The observer hears the sound as having a greater amplitude.
D. The observer hears the sound as having a shorter wavelength

#17. A windsurfer moves at 5 m/s while staying on the crest of a wave, as shown below.

mcas-2015-windsurfer-waves

#29. A seismic wave called a P-wave travels through the solid part of Earth. In a P-wave, the solid particles of Earth move parallel to the direction the P-wave travels. P-waves are which of the following types of waves?
A. electromagnetic
B. longitudinal
C. torsional
D. transverse

#38. At a given temperature, a longitudinal mechanical wave will travel fastest through which of the following?
A. a gas
B. a liquid
C. a solid
D. a vacuum

#45. Essay and Drawing! A floating object moves up and down 15 times in 60 s because of ocean waves.
a. Calculate the period of the ocean waves. Show your calculations and include units in
your answer.
b. Calculate the frequency of the ocean waves. Show your calculations and include units in
your answer.

An additional wave property must be known in order to calculate the velocity of the ocean
waves.
c. In your Student Answer Booklet, identify this additional wave property and draw a wave
diagram showing how the property can be measured.
d. Describe what will happen to the object if the amplitude of the ocean waves increases and all other wave characteristics stay the same

Textbook p.393, #18.

How does increasing the wavelength of a rope by 50 % decreases its frequency by 33 %.

The relation between frequency and wavelength is

$f λ = v$

Then

$f_{1} λ_{1} = f_{2} λ_{2}$

If $f_{1} = f$ , then $f_{2} = 1.50 f$

$λ_{2} = λ_{1} \times \frac{f_{1}}{f_{2}} = λ_{1} \times \frac{f}{1.50 f} = 0.67 λ_{1}$

The new wavelength is 67 % of the original (33 % less than the original).

Learning Standards

2016 Massachusetts Science and Technology/Engineering Curriculum Framework

HS-PS4-1. Use mathematical representations to support a claim regarding relationships among the frequency, wavelength, and speed of waves traveling within various media. Recognize that electromagnetic waves can travel through empty space (without a medium) as compared to mechanical waves that require a medium

SAT subject test in Physics: Waves and optics

• General wave properties, such as wave speed, frequency, wavelength, superposition, standing wave diffraction, and Doppler effect
• Reflection and refraction, such as Snell’s law and changes in wavelength and speed
• Ray optics, such as image formation using pinholes, mirrors, and lenses
• Physical optics, such as single-slit diffraction, double-slit interference, polarization, and color

Peer review

January 17, 2017 3:05 pm

This resource contains 2 lessons

Enter a caption

Image courtesy of the UC San Diego Library

(1) Scrutinizing science: Peer review. UC Museum of Paleontology of the University of California at Berkeley.

(2) In search of quality: The scientific peer review process. EUFIC – The European Food Information Council. A non-profit organisation for science-based information on food and health.

______________________________________________

Scrutinizing Science: Peer Review

Peer review does the same thing for science that the “inspected by #7” sticker does for your t-shirt: provides assurance that someone who knows what they’re doing has double-checked it. In science, peer review typically works something like this:

A group of scientists completes a study and writes it up in the form of an article. They submit it to a journal for publication.
The journal’s editors send the article to several other scientists who work in the same field (i.e., the “peers” of peer review).
Those reviewers provide feedback on the article and tell the editor whether or not they think the study is of high enough quality to be published.
The authors may then revise their article and resubmit it for consideration.
Only articles that meet good scientific standards (e.g., acknowledge and build upon other work in the field, rely on logical reasoning and well-designed studies, back up claims with evidence, etc.) are accepted for publication.

peer-review

Peer review and publication are time-consuming, frequently involving more than a year between submission and publication. The process is also highly competitive. For example, the highly-regarded journal Science accepts less than 8% of the articles it receives, and The New England Journal of Medicine publishes just 6% of its submissions.

Peer-reviewed articles provide a trusted form of scientific communication. Even if you are unfamiliar with the topic or the scientists who authored a particular study, you can trust peer-reviewed work to meet certain standards of scientific quality.

Since scientific knowledge is cumulative and builds on itself, this trust is particularly important. No scientist would want to base their own work on someone else’s unreliable study!

Peer-reviewed work isn’t necessarily correct or conclusive, but it does meet the standards of science. And that means that once a piece of scientific research passes through peer review and is published, science must deal with it somehow — perhaps by incorporating it into the established body of scientific knowledge, building on it further, figuring out why it is wrong, or trying to replicate its results.

– Scrutinizing science: Peer review. UC Museum of Paleontology of the University of California at Berkeley.

______________

https://thelukewarmersway.wordpress.com/2016/02/07/climate-scientists-in-like-flint/

In search of quality: The scientific peer review process

Before a scientific assertion is made public it should be scrutinised for its credibility. Has the scientist drawn justifiable conclusions, based on the data available from sound scientific research?

The peer review process is a form of scientific quality control, where scientists open their research to the scrutiny of other experts in the field (peers).¹

By reviewing and criticising each others’ work, scientists aim to ensure that only original and sound research is published and recognised.

How does it work?

When research is submitted for publication in a peer-reviewed journal, the journal invites several (usually two or more) independent experts to assess the credibility of the research.¹

These experts consider the scientific methods, results and conclusions presented by the authors, asking themselves, if the science is technically sound, if the interpretation is consistent with the data, and if it is new, important or ground-breaking.²

Reviewers usually remain anonymous, are not paid for their assessment, and should not have any conflicts of interest in relation to the research. If a paper does not meet the requirements, based on the peer reviews, the editor can either reject it or deem it acceptable subject to adequate changes, allowing authors to react and revise their paper.

Why is it important?

The peer review process checks that a paper explains clearly how the research was carried out, so that it can be reproduced by others. It also verifies that the methodology is appropriate for the specific field and set of objectives.

Another crucial part of the review process is assessing the originality of new research and the accurate referencing of related published research, particularly if these contrast with the research at hand. The review is also useful for those whose work is being scrutinised; it allows them to fine-tune their manuscript before public release.²

A manuscript is seldom accepted for publication without at least a minor revision.

The review process essentially strives to separate fact from speculation and personal opinion.²

Peer-reviewed research is never beyond criticism however, and any conclusions drawn must be considered in the context of other studies. Ideally, experiments should be repeated to assess whether results can be reproduced; this is how findings are truly substantiated. The real validation, therefore, comes after publication.

Non-peer-reviewed research

Unfortunately, research results often find their way into the public domain without being peer reviewed, and are spread via newspapers, magazines, the internet, television and radio. They may be unpublished findings presented at press conferences, or published findings from a journal that does not use peer review.

Even journals that do use peer review contain some non-peer-reviewed content, such as editorials and letters to the editor. Both scientists and journalists should understand the meaning and importance of peer review and clarify whether or not research they discuss has been peer-reviewed. There are potentially enormous costs to both science and society from the promotion of scientifically weak or flawed research findings.

An imperfect process

The peer review process does not protect against misconduct. It can identify mistakes, but relies on honesty and, as a result, can fail to recognise deliberately fraudulent research. Various organisations have produced integrity guidelines on good research practice aiming to reduce such occurrences.³

On the other side, financial or personal concerns may bias a reviewer’s professional judgement and objectivity. It is vital to consider in advance any factors, which could lead to bias.³

According to the European Science Foundation, preventing and managing such conflicts of interest is crucial in ensuring equity and integrity.³

Sometimes concerns are raised about the influence of the funding body on the design of the study, or the interpretation or reporting of the research outcomes. The peer review process gives credence to research, because the paper has been independently checked and critically evaluated, including the correct scientific interpretation of the results on the basis of other existing evidence – no matter who funded the research.²

Inevitably, there are variations in standards between journals. A journal’s “Impact Factor” reflects how often its papers are cited in other peer-reviewed journals, and gives some indication of importance of the journal in its field – the higher the number, the greater the impact or influence.

The process and culture of checking each other’s work is ongoing in the scientific world. Once a paper has been published, further criticism can be made by the scientific community via letters to the journal editor, discussions at conferences, or direct exchange with the research team behind the study in question. Authors can justify their findings and flaws uncovered can be corrected or retracted.^1,2

This is the nature of science; all work is open to critique by other scientists.

References

Science Media Centre (2012). Peer review in a nutshell: http://www.sciencemediacentre.org/wp-content/uploads/2012/09/Peer-Review-in-a-Nutshell.pdf
Sense About Science (2004). Peer Review and the acceptance of new scientific ideas. London: Sense About Science. http://www.senseaboutscience.org/data/files/resources/17/peerReview.pdf
European Science Foundation (2011). European peer review guide integrating policies and practices into coherent procedures. Strasbourg: European Science Foundation. http://www.vr.se/download/18.2ab49299132224ae10680001647/European+Peer+Review+Guide.pdf

Waves in 2 dimensions

January 11, 2017 6:57 pm

Let’s throw a stone into water and then observe the circular crests and troughs

We see waves propagate in 2 dimensions: along the X-axis, and Y-axis, simultaneously.

http://www.sciencelibrary.info/Wave_Types

Awavefront represents the crest of a wave in 2 dimensions

2-dimensional waves always travel perpendicular to their wavefronts

A wave’s direction is represented by a ray

http://slideplayer.com/slide/6283922/

Here, water waves, or light waves, hit a curved surface

The wavefronts reflect to a point, called the focus.

reflection-water-waves-from-curved-surface

http://www.s-cool.co.uk/gcse/physics/properties-of-waves/revise-it/reflection-of-waves

Refraction of 2-D waves

Refraction is the change in direction of wave propagation due to a change in its transmission medium.

Often seen with light.

Seen with water waves, when they move from deep water into shallow water.

Here light waves refrac as they move from one medium into another (from air into diamond)

In this simplified case, the light waves (or water waves) are all parallel to each other.

$Refraction$

http://www.acs.psu.edu/drussell/Demos/refract/refract.html

Here we see the same thing, but now the rays of light are more realistic.

They emanate from a source, so they are circular, not parallel.

Yet when the rays hit the water, they are approximately parallel, so the result is the same.

snells-law-wavefronts

Snell’s law at PhysicsClassroom.com

Water waves can be refracted

Animation: Wiley Refraction

Animation GCSE Light and water refraction

Here we see water waves changing direction, as they enter shallower waters.

$water-wave-refraction-into-a-bay$

$wave-refraction-diffraction-model-for-la-jolla-shores$

http://www.grossmont.edu/people/gary-jacobson/oceanography-112/wave-model.aspx

From a presentation by Luo Yanjie.

$wave-refraction-23-728$

http://www.slideshare.net/luoyanjie/wave-refraction

From a presentation by Luo Yanjie.

$wave-refraction-25-728$

http://www.slideshare.net/luoyanjie/wave-refraction

Details on the cause of refraction (PhysicsClassroom.Com)

Learning Standards

2016 Massachusetts Science and Technology/Engineering Curriculum Framework

SAT subject test in Physics: Waves and optics

How a computer interprets instructions

January 10, 2017 5:26 pm

How does a computer understand (interpret and execute) a high level programming language?

high-level-vs-low-level-language

What’s the difference between a high-level computer language and a low-level language? How does a computer interpret these languages, so the program can run? What is computer programming?

How does a computer understand a computer program http://guyhaas.com/bfoit/itp/Programming.html

BBC Bitesize Revision: Running a program, the CPU, etc. (a 5 page step-by-step resource) http://www.bbc.co.uk/education/guides/z2342hv/revision/1

How do you communicate with computers? Through a programming language. Source code and language differences: Learntocodewith.me

Break down how code gets translated from the code programmers write, to the code computers read, the difference between compiled and interpreted code, and what makes “just-in-time” compilers so fast and efficient. The Basics of Compiled Languages, Interpreted Languages, and Just-in-Time Compilers

How do computers understand programming languages? How do you “teach” a computer a language? Explanation by Christian Benesch, software engineer and architect (among other explanations) here

How does a computer understand a computer program? Codeconquest.com How does coding work?

What is a program? What is a programming language? Depending on the language used, and the particular implementation of the language used, the process to translate high-level language statements to actions may involve compilation and interpretation. Introduction to Programming (Wikiversity)

Subtractive color

January 6, 2017 1:40 am

There are 2 ways to create color:

additive model/RGB:

Make new colors by adding beams of light

RGB: red, green, blue

subtractive model/CMYK:

Making new colors by adding pigments (dyes, inks, paints)

CMYK: Cyan, Magenta, Yellow, Black

This lesson is on the subtractive color model.

Additive and Subtractive primary colors

Paints/inks/dyes contain pigments, molecules that absorb some frequencies of light, but not others.

When paints/inks/dyes are mixed, the mixture absorbs all the frequencies that each individual one absorbs.

Examples:

Blue paint absorbs red, orange, and yellow light. It reflects the rest (blue, violet, some green)

Yellow paint absorbs blue & violent. It reflects mostly yellow, and some red, orange, and green.

Images by Paul Hewitt

Subtractive When blue and yellow paints are mixed Hewitt

Mixing colored light is called color mixing by addition.
When you cast lights on a stage, you use the rules of color addition, but when you mix paint, you use the rules of color subtraction.

The three colors most useful in color mixing by subtraction are:
• magenta (bluish red)
• yellow
• cyan (greenish blue)

Magenta, yellow, and cyan are the subtractive primary colors, used in printing illustrations in full color.

mixing-colored-pigments

Color printing is done on a press that prints each page with four differently colored inks (magenta, yellow, cyan, and black).

• Each color of ink comes from a different plate, which transfers the ink to the paper.

• The ink deposits are regulated on different parts of the plate by tiny dots.

• The overlapping dots of three colors plus black give the appearance of many colors.

colors-of-ink-used-for-color-illustrations

SlideShare on Color and Light

Learning Standards

SAT subject test in Physics: Waves and optics
• Physical optics, such as single-slit diffraction, double-slit interference, polarization, and color.

Massachusetts Arts Curriculum Framework: The Practice Of Creating
PreK- 4 Visual Arts Standards – Identify primary and secondary colors; predict and demonstrate the effects of blending or overlapping primary colors; demonstrate knowledge of making dark to light values of colors. Identify and use basic two-dimensional hollow and solid geometric shapes (circle, triangle, square, rectangle) and three-dimensional forms (sphere, pyramid, cube).

Grades 5-8 Visual Arts Standards – Create compositions that reflect knowledge of the elements and principles of art, i.e., line, color, form, texture; balance, repetition, rhythm, scale, and proportion. Demonstrate the ability to apply elements and principles of art to graphic, textile, product, and architectural design.

Massachusetts Arts Curriculum Framework
The Arts Disciplines: Visual Arts
PreK–12 STANDARD 2: Elements and Principles of Design

By the end of Grade 4: 2.1 Students will, for color, explore and experiment with the use of color in dry and wet media Identify primary and secondary colors and gradations of black, white and gray in the environment and artwork.
By the end of Grade 8: 2.7 Students will, for color, use and be able to identify hues, values, intermediate shades, tints, tones, complementary, analogous, and monochromatic colors. Demonstrate awareness of color by painting objective studies from life and freeform
abstractions that employ relative properties of color.