Reflection

REFLECTION

• The change in direction of a wavefront at an interface• ie. Light waves reflecting on the waters surface.

• The reflection of light allows us to see objects that do not emit light themselves.

• Basic principles of reflection can be covered include:

If Light not reflected it must be absorbed Lights reflects differently on different surfaces Reflective angle of light

Follow on:

• From Refraction and how colour is made to Reflection and colour

Principle of Reflection

Light that is not reflected must be absorbed

Colour and ReflectionDepending how light is reflected and absorbed it can effect the colour of an object.

all colours reflected = appear white all colours adsorbed = appear Blackabsorbed some and reflected some = Coloured

Gummy Bear experiment

• Line of Green Gummy Bears

• Line of Red Gummy Bears

• Gummy Worm• 1 Red laser Pointer• 2 Green Laser Point • White Light

Gummy bear experiment• First– Red laser on Red

Gummy Bears – Green Laser on Green

Gummy Bears • Next– Red Laser on Green

Gummy Bears – Green laser on Red

Gummy Bears

Gummy bear experiment

• With the White light:– Use on the Red and Green Gummy bears – And Finally run along the Gummy worm

Point of Experiment and Reasoning

• What you should expect from the experiment… • Reasons – Simple/ easy set up– challenges

preconceptions– Very visual – Set Induction and

engagement

Three jar experiment

You will need:

• Three jars •Vegetable oil• 3x Thermometers • Sun • Paper (1x black, 1x white, 1x coloured)

• Check the temperature of the oil in each jar. Record the temperatures every 5-10 minutes for one hour.

Three jar experiment• Facilitate a prediction from the students• How the colours affect the temperature and

students understanding – black = absorption of light – white = reflection of light– Colour = Some reflection and some absorption

Point of Experiment and Reasoning

• If light is not reflected by a material, it must be absorbed

• Connection and transfer or learning/understanding to other topics

• Relate back to real life (clothes, cars)

Video- Light and Colour Bill Nye

• http://www.youtube.com/watch?v=gtgBHsSzCPE

DIFFUSE REFLECTION

SPECULAR REFLECTION

Mirrors and Reflection

The Maze Experiment

• 4-5 mirrors• A target• A Torch or laser pointer• Use the mirrors to redirect the light to the target.

But what’s the point?

• Visually informative• Easy to set up and pack up• Engaging• Promotes collaboration and cooperation• You can use it to create

challenges/competitions• Guided discovery• Great lead-in to discussion and other activities