## Lesson 1: Properties of waves and light

This unit describes the properties of waves and light. It also explains some of the foundamental terminologies used in the study of the propagation of waves and light. The chapter will be concluded with a look at reflection and the law of reflection.

Experiment Experiment to show that Light travels in a straight line
Properties of wave
Source: www.scienceaid.com |
•HOOK: Set the laboratory for students to do an investigation on propagation of light using light source (candle), and three pieces of cardboards with a hole. The aim is to show that light travel in a straight line. Place a candle on the bench and then clamp the three pieces of card in front of the candle, one behind the other - look through the holes (at this stage they're not lined up), and ask volunteers to see if they can see the light from the candle....of course not. Then thread a piece of string through the holes to help line them up and you should be able to see the candle now - indicating that the light is travelling in a straight line. •ACTION: Define the terminologies students need in the unit, example, wavelength, frequency, crest, trough, phrase, and velocity; derive the wave equation and explain reflection/laws of reflection. The teaching strategy to help students remember all the key terms maybe to ask them to make a flash card of all the key terms. The flash card will be required to include the key terms, defination, and a well labelled diagram. •CONSOLIDATION: Solves one problem using the wave equation and give student two other problems to solve in groups (check PROBLEMS). Show the students the following Youtube video to further help to consolidate the lesson. The teacher shares class into two groups to research on “Light as a particle or wave”. Rubric is given and the students are informed that each group will select three students to debate on the this in week 4. One group will try to convince the class that light is a particle while the other will present points to prove that light is a wave. |