pencil appearing bent Equipment: glass or plastic depth of water. Set up when standing in a blocks of various shapes, a ripple tank with beaker of water, or a coin including rectangular and illumination. Place lamp in a mug only becoming triangular; plain paper (A3 if beneath the ripple tank visible when water is possible); power supply; ray to project the image added to the mug. box with single slit (and convex onto the ceiling. Make Discuss with the class the cylindrical lens to make the ray sure the tank is level. basic idea that we see thinner) The depth of water in objects because light part of the ripple tank travels from them to our is reduced by placing a eyes, and then ask how glass block in the tank. the pencil could appear The water above the bent. Elicit the idea that glass should be very the light travelling from shallow and use a low water to air changes frequency wave. direction. Demonstrate using 2) Ask students to work waves approaching the in groups to come up with glass at different five key facts about the angles. Link between way light travels and how changes in wave its direction can be speed and refraction. changed. Give them a Explain that the ripple few minutes, then ask for tank is also acting as contributions to a class model of sound, seismic discussion, recording key and light waves points on the board refracting. Equipment: Ripple tank and accessories, stopwatches, ruler.
pencil appearing bent when standing in a beaker of water, or a coin in a mug only becoming visible when water is added to the mug. Discuss with the class the basic idea that we see objects because light travels from them to our eyes, and then ask how the pencil could appear bent. Elicit the idea that the light travelling from water to air changes direction. 2) Ask students to work in groups to come up with five key facts about the way light travels and how its direction can be changed. Give them a few minutes, then ask for contributions to a class discussion, recording key points on the board Equipment: glass or plastic blocks of various shapes, including rectangular and triangular; plain paper (A3 if possible); power supply; ray box with single slit (and convex cylindrical lens to make the ray thinner) depth of water. Set up a ripple tank with illumination. Place lamp beneath the ripple tank to project the image onto the ceiling. Make sure the tank is level. The depth of water in part of the ripple tank is reduced by placing a glass block in the tank. The water above the glass should be very shallow and use a low frequency wave. Demonstrate using waves approaching the glass at different angles. Link between changes in wave speed and refraction. Explain that the ripple tank is also acting as model of sound, seismic and light waves refracting. Equipment: Ripple tank and accessories, stopwatches, ruler.
gcse-science-planning-document-term-3.docx