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This painting ‘Swans and Elephants’ is by Salvador Dali. What do you see? What do you think today’s lesson might be about?. Reflection. Objectives. To be able to draw Ray diagrams , showing the normal line and the angle of incidence and reflection (knowledge)
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This painting ‘Swans and Elephants’ is by Salvador Dali. What do you see? What do you think today’s lesson might be about?
Objectives • To be able to draw Ray diagrams, showing the normal line and the angle of incidence and reflection (knowledge) • Understand how an image is formed by a plane mirror, and why it is virtual (knowledge) • To apply this understanding to create our own Dali masterpiece!! (synthesis) and to reconsider and evaluate the painting used for today’s bell work (evaluation)
Present New InformationReflective materials Objects that reflect light well: • Have smooth, shiny surfaces and are usually pale colours. • Give clear images because they reflect light regularly. Objects that do not reflect light well: • Have rough, matt surfaces and are usually dark colours. • Give diffuse images (or do not give any images) because they reflect light irregularly.
A plane mirror reflects light regularly so it produces a clear image, which is the same size as the object. The image appears the same distance behind the mirror as the object is in front of it. What is different about the image compared to the object?
What is different about the image compared to the object? • What do you think a simulation is? • Think! – 30s • Pair! – 30s • Share!
When an object is reflected in a plane mirror, left appears as right and right appears as left. This type of reversal is called lateral inversion. What is lateral inversion? What are the key features of a ray diagram?
Construct - Reflection investigation 1. Fix a plane mirror to a piece of paper and draw around it. 2. Draw a normal (at 90°) through the centre of the mirror outline. 3. Use a ray box to shine an incident ray at the mirror – plot the incident and reflected rays. 4.Measure the angles of incidence [i] and reflection [r] and record the results. 5. Repeat for another four angles of incidence.
Construct – spotting patterns What do the results show?
How Science Works - Using reflection Reflection can be very useful. High-visibility strips are very reflective and make sure that this cyclist gets noticed when there is little light. How does a periscope use reflection? The two plane mirrors must be positioned at 45° to each other. Light is reflected at right angles from the top mirror onto the bottom mirror and into the eye of the viewer. Where are periscopes used?
Apply to Demonstrate I– Reflections in Art Evaluation is a high order thinking skill, and is very important For scientists! • Now that we’ve • studied reflection, • evaluate whether this • piece of art obeys the • laws of Physics. • Are the images laterally • Inverted? • Do the images appear • the same distance in • the water as the objects • are out of it? • Is the artist obeying the • laws of physics
Your task: To create your own reflection drawing, where the images reflected are the same shape, but form a different object (like the swans and elephants) Success Criteria: Your drawing will fill a single page of your book It will have water as the mirror It will have a minimum of one object reflecting to produce the image The image will obey the laws of reflection Apply to Demonstrate II If your TG is A/A* try to include More than one object (like the trees and Swans) Hint: Think simple, draw the outline of your object, then its reflection. Fill the details in afterwards Try to think of an initial object that has a shape you can apply to something else, as Dali did with elephant trunks and swan necks
Homework • Write it in your planner – • To find another picture (any artist) that does or doesn't obey the laws of Physics, print it off, and be prepared to explain ‘the Physics of the picture’ next lesson.
Objectives Review How did the practical help you achieve This? • To be able to draw Ray diagrams, showing the normal line and the angle of incidence and reflection (knowledge) • Understand how an image is formed by a plane mirror, and why it is virtual (knowledge) • To apply this understanding to create our own Dali masterpiece!! (synthesis) and to reconsider and evaluate the painting used for today’s bell work (evaluation) How did the practical help you achieve This? What tasks did you do to meet These objectives?