Visible light: reflection, refraction and colour
How light travels, shadows, reflection and refraction, and where colour comes from. Read one part at a time and tap “I know this”. Then test yourself in the quiz.
Know it already? Jump straight to the quiz
Light and shadows
An opaque object blocks all the light, so it casts a clear shadow. The closer the light is to the object, the bigger the shadow. We see a non-luminous object because light from a source reflects off it into our eyes.
| Material | Light | Example |
|---|---|---|
| Transparent | Goes straight through | Window glass |
| Translucent | Only some goes through | Tissue paper, frosted glass |
| Opaque | No light goes through | Wood, a book |
Reflect and refract
- Rough surfaces scatter light in all directions: diffuse reflection.
- A periscope uses two mirrors to see over or around an obstacle.
- A straw in a glass of water looks bent: light bends where it passes between water and air.
Colour
- A rainbow: raindrops bend and reflect sunlight.
- A leaf looks green because it reflects green light; a black object absorbs nearly all the light.
- A white shirt feels cooler in the sun: white reflects, black absorbs.
Remember this and test yourself
- A luminous object gives off its own light (the Sun); the Moon is non-luminous: it reflects.
- Light travels in straight lines. Transparent: all light through; translucent: some; opaque: none.
- Reflection: light bounces off; a smooth, shiny surface gives the clearest image. A mirror image is left-right reversed.
- Refraction: light bends as it enters a new material; that is why a straw in water looks bent.
- A prism splits white light into seven colours (dispersion); violet bends the most, red the least.
Write these points in your book. Read them again the night before the test.
Reflect = light flicks back (bounces). Refract = light bends at a new material. Rainbow colours: “Richard Of York Gave Battle In Vain”.
Important words
First say what the word means, then turn the card over.
Match column A to column B
Tap a word in column A, then its meaning in column B. You can also start in column B.
True or false?
Read the question and the answer. Is the answer right? Tap True or False.
Now the real quiz!
The quiz has many more questions on this topic. Every question shows straight away whether you are right and explains why.
Take the quiz: Visible light: reflection, refraction and colour- Read one part together and ask your child to tell it back in their own words.
- The ticks (“I know this”) are saved on this device only. We never ask for names or emails.
Follows CAPS for Grade 7 Natural Sciences. Always check your teacher’s notes and textbook too.