MR. ABBOTT
Grade 8 Science Study Guide for Chapter 4
Test: FRIDAY , MAY 22ND , 2015.
- What contributions did the following people have to our understanding of light?
- Pythagoras
- Galileo
- Michelson
- Janssen’s
- What is light?
- What is the speed of light?
- Using an example, compare the speed of light to the speed of sound.
- On a diagram of a wave, recognize crest, trough, wavelength and frequency
- Explain wavelength and frequency
- Important: high frequency of waves means that the waves have short wavelengths
- What is visible light?
- What are the colors of visible light, in order started with red? (Roy G Biv)
- Compare the wavelengths, refraction and frequency of colors in the visible light spectrum.
Example: compare yellow to indigo
Answer: Because yellow comes before indigo in Roy G Biv it has a longer wavelength, it
refracts less and has a lower frequency
* Should be able to compare any 2 colors (See first diagram on page 3 of notes)
- What happens to light as it shines through a prism? (see 2nd diagram on page 3 of notes)
- Why do we see certain colors and not others? (the colors we see are reflected and the other colors are absorbed
because of the properties of their wavelengths and therefore, cannot be seen)
- What is the electromagnetic spectrum?
- What is electromagnetic radiation?
- What are the 7 types of electromagnetic radiation, in order, starting with radio waves?
- Name 2 uses for each of the 7 types of electromagnetic radiation.
- What is one positive and one negative effect of infrared, ultraviolet, x-rays and gamma rays?
- Compare types of electromagnetic radiation in terms of wavelength, energy and frequency (you can use the
diagram on page 4 of your notes)
Examples:
1. Compare microwaves to X-ray
- microwaves have a bigger wavelength, less energy and are less frequent
2. Compare ultraviolet rays to visible light
- ultraviolet rays have shorter wavelengths, more energy and are more frequent
3. Gamma rays to visible light
- gamma rays have the shortest wavelengths, most energy and have greater
frequency