Table of Contents
Research, Discoveries & Problem Solving Activities:
OUTCOMES:
Students research, using secondary sources to gather information about science understandings, discoveries and/or inventions that depend on the reflection and refraction of light and how these are used to solve problems that directly affect people's lives, eg mirrors, magnifiers, spectacles and prisms
Students learn:
| SCIENCE | Identify scientific principles underlying bhaviour of light |
| TECHNOLOGY | Record and analyse data |
| ART | Blended multimedia elements |
| ENGINEERING | Design, build and test experimental device(s) |
| MATHEMATICS | Use comparative data to differentiate materials |
Example Introductory Experiment - Where does light come from:
Explain the importance and consequences of light from the sun.
3. Think of examples of things that create light:
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| Where does the sun go after dark? | |
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| Will time travel ever really be possible? | |
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Video 1. Astronomy, light speed & time
- IF UNABLE TO ACCESS YOUTUBE VIDEO (requires Flash) TRY: Viewpure Astronomy, light speed & time
More about how astronomy can look into the past:
| What other interesting questions can you think of about light? | |
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The discussions should show that:
Most people think they know where light comes from. For example, it comes from the sun, from light bulbs, from televisions…. but why it comes from these objects (and other, less obvious sources) is a mystery to many.
No matter what the source, light is generally produced via the same mechanism: energy transfer as electrons change their orbits around nuclei:
As an electron gains energy, it moves away from a nucleus. As an electron moves closer to a nucleus it gives off energy. Light is just energy and thus light can both be absorbed or given off in this process.
Scientists call this process radiation. 1)
This type of 'radiation' is not the same thing as the stuff that will kill you, but it's very similar.
Example Project Idea(s) Using Colour Spectroscopy & Spectography
All of the following projects are simple enough to be done by primary school kids using very cheap, robust and easily available materials.
Spectroscopy for beginners - Make A Super Spinning Colour Mixer:
Build your own super spinning colour mixer' as explained here.
The colours you put on the Super Colour Spinner are the three primary colors: red, blue, and yellow. When you start the wheel spinning, what do you notice about each of the three colour circles on the cardboard disc?
Explain how you think this happens?
More detail: The Newton disk
Save The Planet & The Animals From Micro-bead Madness:
Use a spectral photography/webcam to identify products that contain micro-beads
Avoid further water contamination by checking the ingredients in your mum/dad's favourite brand of exfoliating cleanser.
If the list of ingredients includes polyethylene or polypropylene, two types of plastic commonly used in microbeads.
Use Webcam Spectography To Detect Cancer Risk:
Studies have shown that people who have 11 or more moles on one of their arms could have a higher risk of the deadly skin cancer melanoma.
Students may design a project using a simple webcam to identify (colour) and count the number of moles on a persons arm. Students may create a database to store and analyse their results.
Studies, which were large and lasted at least 15 years, found that women with more moles were more likely to develop breast cancer compared with women who had fewer or none of them.
NSW Cancer Institute on-line risk tool: http://www.darksideoftanning.com.au/reduce_risk/quiz.aspx
Computer recognition: Detecting skin-colored pixels, although seems a straightforward easy task, has proven quite challenging for many reasons. The appearance of skin in an image depends on the illumination conditions (illumination geometry and color) where the image was captured. We humans are very good at identifying object colors in a wide range of illuminations, this is called color constancy. Color constancy is a mystery of perception. Therefore, an important challenge in skin detection is to represent the color in a way that is invariant or at least in sensitive to changes in illumination: http://www.cs.rutgers.edu/~elgammal/pub/skin.pdf
- OpenCV Canny edge detection
- OpenCV or Python Edge Detection Tutorial
- OpenCV edge detection software
- OpenCV recognition of multiple circles in an image
Webcam Spectography & Fingernail Diagnostics
Did you know that your fingernails can provide clues to your overall health?
How could you set up a device to identify fingernail types that might help identify possible health problems as described in the links below?
Measuring Colour Blindness & Colour Perception
Design an experiment to measure how perceptive users are of colour.
Color can be perceived in various degrees across and among species, and with this application, users can test their abilities by selecting the colour sample they see as different than the rest, while being educated about human colour perception.
Why is the night sky dark
Build Your Own Spectroscope
WARNING: Never point your spectrometer towards the sun and never look at directly at, or at reflections of the sun.
The way this spectroscope works is very simple.
The light whose spectrum we want to measure enters through a slit (a very thin hole) into the spectroscope, and gets reflected in our mirror. Then it travels towards the DVD sector, where the light gets refracted.
We can then either look through the viewing windor or we can fix it to a camera (e.g.: a webcam or smart-phone camera) and adjust the position in order to capture and view the spectrum of the light.
The best cheap DIY spectroscope:
Periscope Type DVD Spectroscope (best quality image and low cost DIY design):
- How to build a good quality, DIY periscope DVD spectrometer
- The full set of instructions and plan HERE
- A full size template (to print out) is Detailed information about spectral analysis
Next best DIY spectroscope
This spectrometer is a bit easier to build and requires only some scissors, an offcut from an old CD/DVD and some stiff card. Plan, instructions and lots of excellent resources at Public Labs DIY Spectroscopy:
- Plans DIY Foldable Mini: https://publiclab.org/wiki/foldable-spec
DIY Spectroscopes (advanced projects)
Spectroscopy - Mixing & separating colours:
Assorted links:
WARNING: Never point your spectrometer towards the sun and never look at directly at, or at reflections of the sun.
Now point the spectrometer slit at a light, and look through the hole at the CD. Note the arrows on the sides of the spectroscope that show the directions to the light source, and to look. Try looking at an incandescent light bulb, and then at a fluorescent light bulb. Are all fluorescent lights the same? Try street lights and other light sources. Look at light reflected off of colored paper, or shining through transparent coloured plastic, glass, or juice.
How does white light compare to light reflected from white paper? Does the paper look the same under different lights? Can you tell why colours look ok under some street lights and not others, despite the similar appearance of the lights themselves? (HINT: The lights may look similar to your eye, but not to the spectroscope.)
What happens to the spectrum image if you widen and narrow the spectroscope slit?
Miscellaneous Resources & Links
General
NASA - Optics Guide For Educators
Simple DIY Astronomy Spectroscope
Prism Spectroscope
PublicLabs Oil Testing Kit
InfraGram
Infragram is an online tool for analyzing plant health with near-infrared imagery.
- Infragram website: http://infragram.org/
Motion
Measuring change (heart beat for example) using webcam motion detection.
- Motion magnification: http://people.csail.mit.edu/mrub/vidmag/
Google Deep Dream
Google has spent the last few years teaching computers how to see, understand, and appreciate our world. It's an important goal that the search giant hopes will allow programs to classify images just by “looking” at them: https://en.wikipedia.org/wiki/DeepDream
Enter simple words and a couple of images into an AI program. Tell the program know what those images contain ( what objects - dogs, cats, mountains, bicycles, … ) and give it a random image and ask it what objects it can find in this image. Then, the program will start transforming the image till it can find something similar to what it already knows and thus you see strange artifacts morphing in the dreamed image ( like eyes or human faces morphing in image of a pyramid).
This week, Google announced a breakthrough that could prove its quantum computer is actually using quantum mechanics. When researchers gave the D-Wave 2X a carefully crafted test problem, the 1,000-qubit computer solved it 100,000,000 times faster than a classical computer could.