Light Dispersion (Grade 10 Physical sciences)

Light dispersion is a phenomenon in which white light separates into its different colors (spectrum) when it passes through a medium, such as a glass prism. This happens because different colors of light bend by different amounts as they pass through the prism. Red light bends the least, and violet light bends the most. This bending, or refraction, causes the light to spread out, creating a rainbow-like effect. Dispersion helps explain why we see different colors in a rainbow or through a prism.

1. WAVES,SOUND
AND LIGHT
DISPERSION OF LIGHT
By Ms Tema

2. Let Us Recap
•What do you think happens when light passes
through a prism or a glass of water?
•Have you ever noticed the colors in a rainbow
or on the surface of a CD?

3. Up Next
Here is a short video 1 minute that will
introduce today’s lesson

4. Short Video
Science Projects (2021)

5. Lesson objectives:
•By the end of this lesson, you should be
able to:
•Define dispersion of light
•Describe the process of dispersion of light
through a medium
•Identify and name the colors of the visible
spectrum in the correct order
•Analyze how the dispersion of light occurs in
real-life scenarios

6. What is dispersion of light
•When white light splits into different colors when it
passes through a medium(Sapienza et al., 2012).
•A medium can either be a prism or a glass of water
•What is a spectrum, then?
•A spectrum is the band of colors formed by the
dispersion (Sapienza et al., 2012).
•NB: You might have heard of the 7 rainbow
colors,right? VIBGYOR

7. What are the
examples of
spectrum?
•Natures spectrum- Rainbow
•Fun fact about RAINBOWS- its
rare to see rainbow because
you need both rainfall and
sunshine happening at the
same and it lasts for a few
seconds or minutes
(Colangelo et al., 2015).
•Another example is the back of
a CD OR DvD

8. How a glass prism splits white light into different
colours
• ©SlideShare, Dispersion of light,
(2012) For this, we need the
concept of refraction. Remember
that refraction means the bending
of light.
•Different colors have the same
speed in the air, which is
approximately 3×10^8 m/s
(Sapienza et al., 2012).

9. The speed at which color
travels
•According to Colangelo et al. (2015), All the
colors travel at the same speed in the air, but
the moment they hit the glass prism, the
speed of the different colors changes in the
prism.
•©SlideShare, Refraction of Light, (2014) Red
has the maximum speed, while violet has the
minimum speed.
•Which color is refracted the most?
•Which color is refracted the least?

10. Activity
•Please complete the Class
Activity handed to you

11. Conclusion

12. Conclusion
1. Dispersion of White Light:
- When white light passes through a medium like a prism or water, it splits into various colors.
- This process is called dispersion.
2. Visible Spectrum:
- Dispersion introduces the visible spectrum, which consists of the colors red, orange, yellow, green, blue, indigo, and violet (ROYGBIV).
- These colors are commonly seen in rainbows.
3. Real-Life Examples of Dispersion:
- Rainbows are a natural example of light dispersion.
- The iridescent patterns seen on the back of CDs or DVDs are another example.
4. Refraction and Bending of Light:
- The concept of refraction, or the bending of light, is essential to understanding dispersion.
- As light enters a different medium, its speed changes, causing it to bend and spread into different colors.
5. Significance of Light Dispersion:
- Light dispersion is significant in both natural phenomena, like rainbows, and practical applications, like optical devices.
- Understanding dispersion helps explain various optical effects and their applications.

13. End

14. REFERENCES
Colangelo, G., Hoferichter, M., Procura, M., & Stoffer, P. (2015). Dispersion relation for hadronic light-by-
light scattering: theoretical foundations. Journal of High Energy Physics, 2015(9).
https://doi.org/10.1007/JHEP09(2015)074
Pathak, N. (2012). Dispersion of light PowerPoint presentation. Available from Slideshare at
https://www.slideshare.net/slideshow/dispersion-of-light/10819363?from_search=5 (Accessed 18
August 2024).
Sapienza, R., Coenen, T., Renger, J., Kuttge, M., Van Hulst, N. F., & Polman, A. (2012). Deep-
subwavelength imaging of the modal dispersion of light. Nature Materials, 11(9), 781–787.
https://doi.org/10.1038/nmat3402
Sasi, A. (2014). Refraction of Light PowerPoint presentation. Available from Slideshare at
https://www.slideshare.net/slideshow/presentation1-38284574/38284574 (Accessed 19 August 2024).
Science Projects. (2021). Dispersion of Light [video]. Youtube.
https://www.youtube.com/watch?v=FmFTwLVWmvU