EXPLORE the nature of the light that can be seen by engaging in the following two activities

Activity 1: Construction paper investigation

• Place a piece of colored construction paper on the table and hold a piece of white paper at an angle over the construction paper.
• Look at the underside of the piece of white paper and record your observations. See Activity sheet: Nature of light (RSS-3) (See Activity sheet: Nature of light (RSS-3 below), question 1.
• Repeat with construction paper of various other colors.

Teacher note: Students should observe a colored hue on the bottom of the white paper that represents colored light that has been reflected by the white paper. Our eyes detect this light. The light originated as white light from the room lights (or sunlight if you have the blinds open). The construction paper has the color you see because it is reflecting that color and absorbing all of the others. See teacher notes in the support pages.

Activity 2: Color reflected from colored objects

Do the "Colors Reflected From Colored Objects" demonstration. 

·         This activity is designed to show that if the source of light is limited to one wavelength then something that reflects that same wavelength will still reflect it and things that absorb that wavelength will still absorb it.

·         In this demo only a small portion of the EM spectrum is used. The objects have a particular color because they are absorbing all other colors except the one they are reflecting. We are separating out only a small portion by using a filter that only transmits one portion.

Teacher note: If you do not have colored filters and projectors for this demonstration you could use flashlights and colored cellophane or have the students examine the images at this site or project them.

Prompt students to record their observations and write a brief explanation. See Activity Sheet: Nature of Light (RSS-3) (See Activity sheet: Nature of light (RSS-3 below) questions 2,3,and 4.

Ask which types of EM radiation would be most useful for evaluating coral reefs. 

• See Activity sheet: Nature of light (RSS-3) (See Activity sheet: Nature of light (RSS-3 below), question 5.

·         You should be able to lead them to visible and infrared radiation as the logical choices of what to detect. 

 

 

 

We can learn about coral reefs from what we can see (visible radiation) and what we cannot see (infrared light).

 

·         examples of infrared images of coral reefs. http://walrus.wr.usgs.gov/coralreefs/mapping_hyper.html