Light imitates art
View Sequence overviewStudents will:
- explore what happens when they combine different colours of light.
- identify the colours that are made when different colours are combined.
- explain that light is made up of different colours that, when combined, make ‘white’ light as it appears to humans.
Students will represent their understanding as they:
- create ray diagrams showing shadows created by different colours of light.
- contribute to consensus building discussions about the colours of light.
- explain the formation of shadows by different colours of light.
In this lesson, assessment is formative.
Feedback might focus on:
- how students describe the formation of the shadows cast by their light, and the colours created when mixing the light beams.
- how students apply their understanding of the umbra and penumbra to describe what is happening when the coloured shadows are created.
Whole class
Class science journal (digital or hard-copy)
Materials to create a word wall
Optional: Demonstration copy of Mixing colours Resource sheet
Optional: A glass prism
Optional: A torch
Each group
A small amount of red, blue and green paints
3 x torches, each with the lens coloured (1 x blue, 1 x red, 1 x green). The most effective way to do this is to cover the lens of the torch with transparent or translucent sticky tape, then colour the tape using blue, red and green permanent markers. Alternatively, cover the lens of the torches with blue, red and green cellophane. After the lesson the tape/cellophane can be removed and the torches can be used for other purposes.
If you do not have enough torches available for three per group, the investigation can be done on a rotational basis alongside a supplementary investigation.
Optional for supplementary investigation—option 1
Sticky tape
3 x mirrors
Optional for supplementary investigation—option 2
3 x pieces of cardboard
3 x pieces of foil large enough to cover the pieces of cardboard
Glue
Optional for supplementary investigation—option 3
Access to view the Simple Science: DIY Kaleidoscope YouTube video
Cardboard tube
Mirror paper or aluminium foil
Ruler
Scissors
Cardboard circle, about 10cm in diameter, or a compass or items to trace to make a circle
Coloured textas
Each student
Individual science journal (digital or hard-copy)
Mixing colours Resource sheet (or create their own)
Lesson
Re-orient
Review the definition of refraction, and the agreed-upon claim about what happens as light travels through water from the previous lesson.
The Inquire phase allows students to cycle progressively and with increasing complexity through the key science ideas related to the core concepts. Each Inquire cycle is divided into three teaching and learning routines that allow students to systematically build their knowledge and skills in science and incorporate this into their current understanding of the world.
When designing a teaching sequence, it is important to consider the knowledge and skills that students will need in the final Act phase. Consider what the students already know and identify the steps that need to be taken to reach the level required. How could you facilitate students’ understanding at each step? What investigations could be designed to build the skills at each step?
Read more about using the LIA FrameworkIdentifying and constructing questions is the creative driver of the inquiry process. It allows students to explore what they know and how they know it. During the Inquire phase of the LIA Framework, the Question routine allows for past activities to be reviewed and to set the scene for the investigation that students will undertake. The use of effective questioning techniques can influence students’ view and interpretation of upcoming content, open them to exploration and link to their current interests and science capital.
When designing a teaching sequence, it is important to spend some time considering the mindset of students at the start of each Inquire phase. What do you want students to be thinking about, what do they already know and what is the best way for them to approach the task? What might tap into their curiosity?
Read more about using the LIA FrameworkMixing colours
Ask students how they might describe the colour of light. Prompt them to consider how light ‘lights up’ the classroom, and what it looks like when we look at a ‘concentrated beam’ of light, like when we shine a torch onto our hand, or when they focused the beam/ray of light through the slit in the cardboard in the previous lesson.
Ask students to describe any experiences or observations of light being a different/specific colour, and how they think that happened (e.g. coloured light bulbs, rainbows after a storm, rainbows when light reflects off water or glass).
Next discuss what students know about mixing colours, for example when painting. Ask students how different colours are made.
Optional: Discuss primary and secondary colours and the colour wheel.
Pose the question: Does mixing different coloured lights make the same colours as mixing different coloured paints?
The Inquire phase allows students to cycle progressively and with increasing complexity through the key science ideas related to the core concepts. Each Inquire cycle is divided into three teaching and learning routines that allow students to systematically build their knowledge and skills in science and incorporate this into their current understanding of the world.
When designing a teaching sequence, it is important to consider the knowledge and skills that students will need in the final Act phase. Consider what the students already know and identify the steps that need to be taken to reach the level required. How could you facilitate students’ understanding at each step? What investigations could be designed to build the skills at each step?
Read more about using the LIA FrameworkThe Investigate routine provides students with an opportunity to explore the key ideas of science, to plan and conduct an investigation, and to gather and record data. The investigations are designed to systematically develop content knowledge and skills through increasingly complex processes of structured inquiry, guided inquiry and open inquiry approaches. Students are encouraged to process data to identify trends and patterns and link them to the real-world context of the teaching sequence.
When designing a teaching sequence, consider the diagnostic assessment (Launch phase) that identified the alternative conceptions that students held. Are there activities that challenge these ideas and provide openings for discussion? What content knowledge and skills do students need to be able to complete the final (Act phase) task? How could you systematically build these through the investigation routines? Are there opportunities to build students’ understanding and skills in the science inquiry processes through the successive investigations?
Read more about using the LIA FrameworkColours of light
If you do not have enough torches available for three per group, student groups can rotate between this investigation and the supplementary investigation below.
Using a demonstration copy of the Mixing colours Resource sheet explain and discuss the steps of the following investigation as required.
Students work in collaborative teams to investigate what colours are made when they mix different combinations of red, blue and green paint, including when they mix all three colours together.
Students then combine different combinations of red, blue and green light. Using the 3 torches with coloured lenses, they shine each colour onto a white wall (or a white piece of paper affixed to the wall), merging the colours of light in each combination and recording the colour that is made, including when all three colours are merged.
Finally, students place a small object in the merged beam from all three torches and record what the shadow looks like using drawings, descriptions and/or photographs. Using an object with lots of edges, protuberances or moving parts will create the best results.
The main part of the shadow, the umbra, will be dark with no colour. However the lighter part of the shadow, the penumbra, will show different colours, including colours that are not being emitted by the torches such as yellow. The objects edges and protuberances will ensure that a penumbra (or multiple penumbra) will be seen, providing students with a more detailed experience of the phenomenon. Read the embedded professional learning The colours of light for more information.
The colours of visible light
What colour is light?
Students will most likely describe the colour of light as being clear or transparent, especially in terms of how it illuminates a classroom. A more concentrated beam of light will be white in appearance but is also transparent.
Scientifically speaking, visible light is white. This 'white' or visible light is actually made up of many different colours/wavelengths of visible light. Each colour changes the angle of its path in a unique way as it moves into a new substance. Red light, for example, bends less than blue. This different angle change means that white light can be separated into its different visible colours and this is what happens when light is shone through a prism—the different colours become visible. You may remember them being taught as ROYGBIV (red, orange, yellow, green, blue, indigo and violet—although the distinction between indigo and violet is questionable).
A similar refraction of sunlight through raindrops separates the visible colours and causes a rainbow.
Our eyes have three special cells in the retina that detect colour. Each cell can only detect one colour of light. One type of cell detects red light, another detects green light, and the final type detects blue light. For this reason, the primary colours of light are red, green and blue (notice they are different to the primary colours of paint). When red, green and blue light is mixed, we see white light. If one of the colours are filtered out, then our brain interprets it as a different colour. For example, when blue light is removed, the remaining red and green light appears yellow. Other secondary colours are magenta (purple = red+ blue) and cyan (turquoise = green + blue).
Students will most likely describe the colour of light as being clear or transparent, especially in terms of how it illuminates a classroom. A more concentrated beam of light will be white in appearance but is also transparent.
Scientifically speaking, visible light is white. This 'white' or visible light is actually made up of many different colours/wavelengths of visible light. Each colour changes the angle of its path in a unique way as it moves into a new substance. Red light, for example, bends less than blue. This different angle change means that white light can be separated into its different visible colours and this is what happens when light is shone through a prism—the different colours become visible. You may remember them being taught as ROYGBIV (red, orange, yellow, green, blue, indigo and violet—although the distinction between indigo and violet is questionable).
A similar refraction of sunlight through raindrops separates the visible colours and causes a rainbow.
Our eyes have three special cells in the retina that detect colour. Each cell can only detect one colour of light. One type of cell detects red light, another detects green light, and the final type detects blue light. For this reason, the primary colours of light are red, green and blue (notice they are different to the primary colours of paint). When red, green and blue light is mixed, we see white light. If one of the colours are filtered out, then our brain interprets it as a different colour. For example, when blue light is removed, the remaining red and green light appears yellow. Other secondary colours are magenta (purple = red+ blue) and cyan (turquoise = green + blue).
The Inquire phase allows students to cycle progressively and with increasing complexity through the key science ideas related to the core concepts. Each Inquire cycle is divided into three teaching and learning routines that allow students to systematically build their knowledge and skills in science and incorporate this into their current understanding of the world.
When designing a teaching sequence, it is important to consider the knowledge and skills that students will need in the final Act phase. Consider what the students already know and identify the steps that need to be taken to reach the level required. How could you facilitate students’ understanding at each step? What investigations could be designed to build the skills at each step?
Read more about using the LIA FrameworkThe Investigate routine provides students with an opportunity to explore the key ideas of science, to plan and conduct an investigation, and to gather and record data. The investigations are designed to systematically develop content knowledge and skills through increasingly complex processes of structured inquiry, guided inquiry and open inquiry approaches. Students are encouraged to process data to identify trends and patterns and link them to the real-world context of the teaching sequence.
When designing a teaching sequence, consider the diagnostic assessment (Launch phase) that identified the alternative conceptions that students held. Are there activities that challenge these ideas and provide openings for discussion? What content knowledge and skills do students need to be able to complete the final (Act phase) task? How could you systematically build these through the investigation routines? Are there opportunities to build students’ understanding and skills in the science inquiry processes through the successive investigations?
Read more about using the LIA FrameworkKaleidoscope
This supplementary investigation can be omitted, along with any related questions in the following Integrate routine. However, it is a worthwhile inclusion as students may wish to explore kaleidoscopes as part of their final sculpture/artwork.
In this investigation students further explore reflections by making a simple kaleidoscope. They can do this individually or in teams, depending on available resources.
Three methods students can use to build kaleidoscopes:
- Connect three mirrors of the same size using sticky tape to tape the edges together to create a triangular prism shape, with the reflective surfaces facing inwards.
- Use three pieces of card covered with aluminium foil to replicate the reflective surfaces of the mirrors.
- Create the more advanced, yet still easily constructed kaleidoscope demonstrated in the Simple Science: DIY Kaleidoscope YouTube video.
Students look at specific objects/location in the classroom/school grounds through the kaleidoscope, describing what they can see in each reflective surface. They experiment by looking at different colours and objects.
Optional: Have a commercially produced kaleidoscope available for students to examine.
Optional: Students write an explanation of how a kaleidoscope works using scientific language.
The science of kaleidoscopes
How does a kaleidoscope work?
A kaleidoscope contains two or more mirrors or reflective surfaces inside a tube. These mirrors are placed at an angle so that their reflection overlaps. One end of the tube is typically filled with colourful items such as plastic or glass beads.
As light enters the end of the tube it hits the mirrors and bounces off in another direction, where it hits another mirror and bounces off again, and so on.
When an observer looks into the opposite end of the tube, they see a variety of patterns created by the perpetual reflections of the colourful materials at the other end of the tube. These patterns can be changed as the tube is rotated.
A kaleidoscope contains two or more mirrors or reflective surfaces inside a tube. These mirrors are placed at an angle so that their reflection overlaps. One end of the tube is typically filled with colourful items such as plastic or glass beads.
As light enters the end of the tube it hits the mirrors and bounces off in another direction, where it hits another mirror and bounces off again, and so on.
When an observer looks into the opposite end of the tube, they see a variety of patterns created by the perpetual reflections of the colourful materials at the other end of the tube. These patterns can be changed as the tube is rotated.
The Inquire phase allows students to cycle progressively and with increasing complexity through the key science ideas related to the core concepts. Each Inquire cycle is divided into three teaching and learning routines that allow students to systematically build their knowledge and skills in science and incorporate this into their current understanding of the world.
When designing a teaching sequence, it is important to consider the knowledge and skills that students will need in the final Act phase. Consider what the students already know and identify the steps that need to be taken to reach the level required. How could you facilitate students’ understanding at each step? What investigations could be designed to build the skills at each step?
Read more about using the LIA FrameworkFollowing an investigation, the Integrate routine provides time and space for data to be evaluated and insights to be synthesized. It reveals new insights, consolidates and refines representations, generalises context and broadens students’ perspectives. It allows student thinking to become visible and opens formative feedback opportunities. It may also lead to further questions being asked, allowing the Inquire phase to start again.
When designing a teaching sequence, consider the diagnostic assessment that was undertaken during the Launch phase. Consider if alternative conceptions could be used as a jumping off point to discussions. How could students represent their learning in a way that would support formative feedback opportunities? Could small summative assessment occur at different stages in the teaching sequence?
Read more about using the LIA FrameworkDiscussing results
Share and discuss students’ results of the investigation on the mixing of different coloured lights.
- What colours did you make when you mixed the different paint combinations?
- What colours did you make when you mixed the different light combinations?
- Where the colours the same?
- What did the shadow look like when you mixed the light beams?
- How where the different from the other shadows we have investigated?
- A part of the shadow (or the umbra) was black, but some parts (the penumbra) were different colours.
- Why do you think this happened?
- Where the three colours of the light were mixed together the light looked white, and the shadow was black. In the parts where only two of the colours were mixed together, or the coloured beam of light was not mixed with another, the shadows were different colours.
- Could you make yellow when you mixed the paints?
- No, yellow is a primary colour in terms of pigment, and cannot be made by mixing different coloured paints/crayons etc.
- Could you see yellow when you mixed the different light combinations?
- Yes, yellow can clearly be seen between the green and the red, particularly when the shadow is created by placing an object in the mixed beams of light.
- What does this tell you about the primary colours of pigment (paint, dye etc.) and the primary colours of light?
- The primary colours of light are red, blue and green. They combine in different ways to make the colours we can see in a rainbow for example. The colours of pigment are different—they are blue, red and yellow. To make yellow light we combine red and green. But you can’t make yellow paint the same way.
- What are some objects that we use every day that rely on the combination of light?
- Televisions, computers, mobile phones etc. The screens on these devices use combinations of pixels of light to create the colours that make images on the screen.
- What did you see when you looked through your kaleidoscope?
- How do you think a kaleidoscope works?
- Why might we decide to add more folds to the foil/mirror paper?
- What would happen if we added more folds to the foil/mirror paper?
Shine the beam of a torch through a glass triangular prism. Alternatively, if you don't have a glass triangular prism available, watch a video of this being demonstrated.
Through questioning, draw out students’ observations, including the colour of the light before it hits the prism, what happens as the light travels through the prism, and the colours that can be seen.
Allow students time to complete the final section of their Mixing colours Resource sheet, explaining what is happening when the coloured shadows are created.
Reflect on the lesson
You might:
- add new words and images to the word wall or glossary.
- add to the W and H sections of the TWLH chart.
- discuss how the learning from this lesson will be relevant to building their light sculptures at the end of the sequence:
- How might they consider colour when designing their sculptures?
- How could they change the colours people see? The colours of the shadows cast?
