Science Chapter: Light and Spectrum

Isaac Newton's Discovery

• Newton discovered in 1666 that white light can be separated into different colors using a triangular prism.
• Sunlight, when passed through a prism, breaks down into the spectrum of colours.
• The colours in the spectrum gradually blend into one another.

The Spectrum

• The spectrum is the range of colours visible when white light separates.
• The colours are red, orange, yellow, green, blue, indigo, and violet (ROY G BIV).
• Originally, Newton identified five or six colours, but seven are now recognised.

Dispersion

• Dispersion is the splitting of white light into different colours due to the bending of light (refraction).
• Each color in white light bends at a slightly different angle as it passes through a prism.
• Violet light bends the most, while red light bends the least.

Rainbows

• Rainbows are formed when water droplets in the air cause the dispersion of light.
• Conditions required for a rainbow:
  • Sunlight must be present.
  • Rain or small water droplets are needed.
  • The sun must be behind the observer.
• The light reflects inside the water droplets.

Questions and Answers (from the worksheet)

• Question 1: What is the process by which white light is split into different colours?
  • Answer: Dispersion.
• Question 2: Who discovered that white light can be split into a spectrum of colours?
  • Answer: Isaac Newton.
• Question 3: Which piece of equipment is used to separate white light into its colours?
  • Answer: Triangular glass prism.
• Question 4: Which colour of light is refracted the least when passing through a prism?
  • Answer: Red.
• Question 5: What is the correct order of colours in the spectrum?
  • Answer: Red, orange, yellow, green, blue, indigo, violet (ROY G BIV).