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Reflection. 7 June, 2014. Starter Question: How big does a mirror have to be so you can see a reflection of your whole height?. Keywords Incident ray, reflected ray, angle of incidence, angle of reflection, normal, plane, perpendicular, ray diagram, virtual image .
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Reflection 7 June, 2014 Starter Question: How big does a mirror have to be so youcan see a reflection of your whole height? Keywords Incident ray, reflected ray, angle of incidence, angle of reflection, normal, plane, perpendicular, ray diagram, virtual image.
All students should be able to: Carry out practicals safely to describe how objects are reflected. Most students should be able to: Be able to draw correct ray diagrams for reflected objects and state the Law of Reflection. Some students should be able to: Describe the rules of reflection and explain what a virtual image is. Outcomes
We will answer this at the end. Starter: How big does a mirror have to be so youcan see a reflection of your whole height?
How is light reflected? Your teacher will demonstrate the reflection practical to you. SAFETY: Light bulbs will be HOT and make ray boxes hot. Wait for them to cool down before tidying away. Practical Time
1) Angle of incidence = Angle of reflection (measured from the normal line, (the line perpendicular to the mirror plane surface)) Law of reflection – check your diagram: normal
Mirror images from a plane mirror are virtual images. This means that if you put a screen behind a mirror reflecting your image you would not get an image of your face on that screen. The image isn’t real. This is the difference, in a real image you can put a screen in front of the rays of light and produce an image. (there aren’t actually any rays of light behind a mirror – it just looks like there are.) Constructing mirror images
Your teacher will demonstrate Pepper’s Ghost. How could this have been used by magicians in the past? How does it work? Pepper’s Ghost
1 Sketch a letter and what its reflection looks like in the mirror. 2 Use the instructions from the board to draw ray diagrams of your initials Practical 2 – constructing mirror images Object mirror Reflected image
Rules of reflection: The image is always: Rule 1: the same …………… behind the mirror as the object is in front. Rule 2: The same ……… as the object. Rule 3: ………… inverted (left becomes right and right becomes left). You have found out the rules of reflection: laterally distance size
1) Write down the law of reflection Draw a diagram of a person standing side on in front of 3 mirrors: 1 the size of their face, 1 the size of half their body, 1 the full length of their body 2) How big does the mirror have to be? 3) Explain what the image looks like - what are the rules of reflection? 4) What is a virtual image? Plenary: The big Q: How big does a mirror have to be so you can see a reflection of your whole height? C B A A*