Lenses+and+light

//N.B. this is a double lesson//

Recall the meaning of refraction. Explain why refraction happens. Draw ray diagrams to show what happens when light goes from one material to another. Explain how lenses work.
 * Objectives (what you will learn this lesson)**


 * Starter**
 * Key term quiz / review completed homework

> > media type="file" key="ES8_Kd155_18ani.swf" width="528" height="528" > > media type="file" key="ES8_Kd154_10ani.swf" width="531" height="531"
 * Activities**
 * 1) What causes refraction read through page 154 of Exploring Science 8 together as a class
 * 2) [|How does refraction work]? look at this presentation together as a class
 * 3) Watch the demonstration of refraction in a rectangular block ([|this simulation] can help). Setup your own example, draw and label it and measure the angles (p154 in Exploring Science will help you with this). Paste your example into your exercise book. Is there a relationship between the angles of incidence and refraction? Can you explain the relationship. Write a sentence of two under your diagram.
 * 4) Review refection by using this simulation to checking your understanding:
 * 1) Now complete the [|questions on refraction]
 * 2) Investigate how lenses work. Magnify and shrink objects then see how light rays travel through them. Now you are ready to complete the [|worksheet on eyes and spectacles]
 * 3) Extension: Read about [|total internal reflection], watch the animation below. Now investigate with a semi-circular glass box and see if you can get in to happen. Now you are ready to answer the questions on the worksheet.

Review completed classwork / key term quiz Look at the [|worksheet] together with your partner see how many labels you can complete with your book closed
 * Summary**

[|Refraction effects] - watch the demonstration in class, try the trick on your parents and then complete, print-off and stick the worksheet into your exercise book**.**
 * Homework**