New light technologies, such as electric lights and fibre optics, have changed human lives in the last 200 years. How will new light technology continue to change communications, entertainment, and education? Watch this video to learn more about the
future of light technology.
Lesson C12: The Future of Light Technology
Figure C.3.12.1 β Li-Fi technology uses light to connect digital devices to the internet.
Figure C.3.12.2β Li-Fi internet connections download and upload information quickly.
Figure C.3.12.3β Using light sources for data transfer could someday replace Wi-Fi.
Reading and Materials
for This Lesson
Science in Action 8
Reading: Pages 239β244
Materials:
Cardboard, white paper, pencil, round object (like a jar lid), scissors, glue, ruler, colouring markers (red, green, and blue), string (1 meter).
Faster Wireless Connections
Transferring information to digital devices through the internet has gotten much faster over time. Computers originally connected to the internet through slow dial-up telephone connections. The development of broadband cables and Wi-Fi made connecting
to the internet much faster. Electric signals enter a building through a cable, where the signals are received by a modem. A Wi-Fi router changes the electric signals into radio waves, and sends the radio signals to digital devices like smartphones
and laptops.
A new type of internet technology has recently been invented, called Li-Fi internet. Li-Fi technology uploads and downloads information 100 times faster than Wi-Fi internet.
Li-Fi uses lights as routers, to send signals to digital devices as quick light pulses. Digital information is represented in patterns of ones and zeros, which correspond to electricity being turned βonβ and βoffβ in a computer chip circuit. Just
like you can turn an electric circuit on and off, you can turn light on and off. Li-Fi routers turn light on and off so quickly that the human eye does not detect any flickering of the lights.
Watch More
Li-Fi Internet
This video gives a short overview of Li-Fi technology.
Watch this video to see a demonstration of Li-Fi internet technology.
Try It!
Mixing Light
Screens emit different amounts of red, green, and blue light, to make the brain perceive different colours. Try this online simulation to see what happens when red, green, and blue light combine in different proportions.
Download:
DOWNLOAD this document. It provides a space for
you to write answers to questions later in this activity. It also provides a chart for you to record your observations.
Select and click on the icon that says βRGBβ Bulbs, like in the picture below.
Adjust the colour light sliders to the following combinations and record what colour you see in a chart like the one below. You can make your own or use the one in the document you downloaded.
βFullβ means to move the light slider all the way to the top, turning on the light completely (Figure C.3.12.4).
βHalfβ means to move the light slider halfway to the top (Figure C.3.12.5).
βOffβ means to move the slider all the way to the bottom, turning off the light completely (Figure C.3.12.6).
Many people know how colours of paint combine. You probably learned in elementary school that blue and red make purple, red and yellow make orange, and blue and yellow make green. This is true of how solid paint pigments combine to absorb and
reflect light. However, your eyes interpret coloured light differently. You might have been surprised to see that red and blue light made a bright pink magenta colour, instead of purple. You might have been surprised to see that red and green
light combined to make yellow, instead of the brown colour you would expect when mixing red and green paint.
Figure C.3.12.8β Television screens emit small pixels of red, green, and blue light.
Screen Time
We depend on screens to transfer visual information in the modern world. Televisions, computers, tablets, and smartphones all have screens.
Figure C.3.12.9β The eye interprets different combinations of red, green, and blue light as different colours.
Screens contain pixels that emit red, green, and blue light. This is sometimes described as RGB colour space. Cone cells on the human retina are activated by red, green, and blue light. Different combinations of red, green, and blue are interpreted by
the brain as different colours. For example, the combination of red and green light activates your red and green cones, and is interpreted by the brain as yellow light. Your brain interprets green and blue light as a turquoise colour called cyan.
Red and blue light combine to form a pink colour called magenta. Combining light in RGB colour space is called additive colour mixing.
Color printers use a different colour space called CMYK. This stands for cyan, magenta, yellow, and key, which is black. These four colours of ink are used in printers. A printer combines tiny dots of different coloured ink on a white page. The
ink dots absorb some colours of light and reflect back other colours. Your brain interprets the combination of dots as different colours. For example, a pattern of evenly-spaced yellow and cyan ink dots is interpreted by your brain as the colour
green. Yellow ink absorbs blue light, cyan absorbs red light, and so the only type of light that can be reflected back to your eyes is green light. Because CMYK colour space depends on the absorption of colour, it is also called subtractive color mixing.
People who work in media, like graphic designers and photo editors, need to understand both RGB and CMYK colour spaces. They need to understand how RGB colour affects the appearance of images on a screen, but also how an RGB screen setting translates
to a similar CMYK pattern for printing.
Figure C.3.12.10β Printers combine cyan, magenta, yellow, and black ink.
Figure C.3.12.11β Colours can be formed by adding or subtracting colours of light.
Watch More
How Colours Work
Watch this video to see how our brains perceive different colours with our red, green, and blue cones.
This experiment demonstrates how additive light can be separated into its components.
Try It!
Disappearing Colour Wheels
Try making some spinning colour wheels to demonstrate additive colour mixing.
Materials:
Cardboard
White paper
Pencil
Round object (like a jar lid)
Scissors
Glue
Ruler
Colouring markers (red, green, and blue)
String (1 meter)
Safety Warning
Take care with scissors; don't cut yourself or anyone else!
The positions of the red, green, and blue sections on the circle were constantly changing as you spun the circle. Any particular position was quickly changing between red, green, and blue. As a result, these three colours of reflected light
were constantly reaching your retina and were interpreted by your brain as white light.
Red and green light would activate red and green cones in your retina, and your brain would interpret this as the colour yellow.
Connections
Figure C.3.12.12β ο»ΏSpecial goggles are used to see virtual reality images.
Figure C.3.12.13β Special smartphone apps can be viewed as virtual reality images.
Figure C.3.12.14β As the wearer moves their head, their view of the virtual world changes.
Connections β Technology >> Virtual Reality
Virtual reality technology creates three-dimensional stereoscopic images that look like the viewer is seeing them in real life. Currently, virtual reality
technology mostly simulates our sense of sight. In order to make an experience more realistic, the other senses like touch and smell need to be simulated as well.
Virtual reality technology is not just used for entertainment. This technology is very useful for training people how to react in different situations. Virtual reality simulations safely allow people to learn how to respond in dangerous situations,
such as firefighting and rescue operations. Virtual reality simulators train pilots how to fly airplanes. Virtual reality technology can even be used to help people gain confidence interacting with other people.
Virtual reality equipment and software can be expensive, but Google Cardboard is an exception. This technology uses a cardboard VR headset and shared virtual reality resources for new users
to get a view of some virtual worlds.
Watch More
Making the Most of Virtual Reality Technology
This video explains how smartphone virtual reality apps work. You can drag this video to view it from multiple directions.
Watch this video to see how virtual reality technology helps people overcome phobias, or fears.
This video explains how virtual reality technology is helping teenagers learn better skills for interacting with other people.
Make sure you have understood everything in this lesson. Use the Self-Check below, and the Self-Check & Lesson Review Tips to guide your learning.
Unit C Lesson 12 Self-Check
Instructions
Complete the following 6 steps.
Don't skip steps β if you do them in order, you will confirm your
understanding of this lesson and create a study bank for the future.
ANSWER all the questions on the downloaded quiz in the spaces provided. Think carefully before typing your answers. Review this lesson if you need to. Save your quiz when you are done.
COMPARE your answers with the suggested "Self-Check Quiz Answers" below. WAIT! You didn't skip step 2, did you? It's very important to carefully write out your own answers before checking the suggested answers.
REVISE your quiz answers if you need to. If you answered all the questions correctly, you can skip this step. Revise means to change, fix, and add extra notes if you need to. This quiz is NOT FOR MARKS, so it is perfectly OK to correct
any mistakes you made. This will make your self-check quiz an excellent study tool you can use later.
SAVE your quiz to a folder on your computer, or to your Private Files. That way you will know where it is for later studying.
CHECK with your teacher if you need to. If after completing all these steps you are still not sure about the questions or your answers, you should ask for more feedback from your teacher. To do this, post in the Course Questions Forum,
or send your teacher an email. In either case, attach your completed quiz and ask; "Can you look at this quiz and give me some feedback please?" They will be happy to help you!
Be a Self-Check
Superhero!
Self-Check Quiz Answers
Click each of the suggested answers below, and carefully compare your answers to the suggested answers.
If you have not done the quiz yet β STOP β and go back to step 1 above. Do not look at the answers without first trying the questions.
High resolution images simulate real-life situations more closely than low resolution images. Low resolution images are not going to appear realistic. The eyeβs retina contains a large number of receptors capable of producing a smooth
high-resolution image so any technology wishing to reproduce realistic images needs to project those images in high resolution.
A larger camera sensor contains more space to collect light and record it as many pixels. An image with a greater number of pixels has a higher resolution. Images with higher resolution look smoother and sharper, especially when they are enlarged
on billboards and movie screens.
There are different perspectives about the effectiveness of virtual reality simulations. Virtual reality is becoming increasingly effective at producing visual images that simulate real life. Virtual reality can help people to feel like they
are in a real-life situation. However, if virtual reality does not engage senses other than vision, it is not exactly the same as being in a real-life situation.
The colour-detecting cones of the human retina are activated the most by red, green, and blue light. When combinations of red, blue, and green light are emitted a screen, our cones are highly stimulated, and we are able to see bright colours.
Reading and Materials
for This Lesson
