Light Demos and Mini Labs 1.What have we learned? 2.What does it all mean? Copyright 2008 PresentationFx.com | Redistribution Prohibited | Image © 2008 Thomas Brian | This text section may be deleted for presentation.PresentationFx.com

M ini - L ab 1 Laser Lenses

Refraction of Light Since the double convex lens is curved on both sides, the light is bent again as it leaves the lens and the path of the light is completely reversed, producing a real image. Convex Lenses

Refraction of Light Convex Lenses The real image is an image that looks just like the original object, but appears upside down.

Refraction of Light A lens can be a curved piece of glass or plastic. Sometimes water can even act as a lens. A double convex lens’s job is to redirect light reflecting off an object and bend it to form what is called a real image.

Refraction of Light Convex Lenses They are thicker in the middle than at the edges. Form virtual images and real images.

M ini - L ab 2 Light goes for a swim More light refraction due to light entering and exiting different substances Light travels a bit faster in air than it does underwater It slows down and changes direction when it enters something new.

Refraction of Light What happened to the beam of light as it entered the water in the fish tank? Why did the pencil appear broken when you placed it in the water?

Refraction of Light Refraction: The bending of a light wave as it passes between two substances in which the speed of the wave differs. Light slows down when it enters the water, causing the ray of light to bend. Light moves ¾ as fast in water as it does in a vacuum. Light moves 2/3 as fast in glass as it does in a vacuum.

Refraction of Light

M ini - L ab 3 View the spectrum Which wavelengths do you see in each gel cyan ROYGBIVROYGBIV magenta ROYGBIVROYGBIV yellow ROYGBIVROYGBIV

Color Subtraction In physics, BLACK is the absence of color and WHITE is the presence of all color. What does this mean? If something appears white, it is because all the colors of the visible light spectrum are being reflected into your eye. If something appears black, it is because all the colors of the visible light spectrum are being absorbed by the substance and none of the light is being reflected into your eye.

Color Subtraction Each pigment absorbs color Combining more colors absorbs or takes away more light, so adding or mixing pigments is called color subtraction. Combining the primary colors of light (blue, green, and red) creates secondary colors of light (cyan, yellow, and magenta). If you combine all three, you get white light so this is called color addition.

Light Absorption and Reflection Why does a red car look red? What Happens to the Light that makes us see red? An object is “seen” only when the object emits or reflects light to the eye. You “see” the color that is being reflected. The other colors are absorbed.

Light Absorption and Reflection Absorption: The transfer of light energy to particles of matter. Reflection: When light bounces off a surface instead of passing though it. Would you rather wear a black t-shirt or a white t-shirt on a sunny day in July? White reflects light, black absorbs it. Copyright 2008 PresentationFx.com | Redistribution Prohibited | Image © 2008 Thomas Brian | This text section may be deleted for presentation.PresentationFx.com

M ini - L ab 4 Through the Looking Glass

M ini - L ab 5 The Electromagnetic Spectrum

M ini - L ab 6 Around the World with Mirrors

1 Dr. Pinkham’s M ini - L ab 1 Reflection of light: Mirror mirror on the wall

Reflection of Light The Law of Reflection Light reflects off surfaces at the same angle it made contact with the surface. Angle of Incidence = Angle of Reflection

Reflection of Light When you wake up in the morning, why do you check your reflection in the mirror, not in your bath towel? If everything you see reflects light, why can’t you see your reflection in the chalkboard?

REGULAR Reflection of Light Occurs when light beams are reflected at the same angle allowing you to see your reflection.

Diffuse Reflection: Occurs when light beams reflect at many different angles, preventing you from seeing your reflection. IRREGULAR Reflection of Light

Human skin looks smooth but when magnified it is an incredibly uneven surface. We don’t use skin as a mirror!

2 Dr. Pinkham’s M ini - L ab 2 Black, White, and Grey

Light Absorption and Reflection What happened? Why was there a difference in temperature?

3 Dr. Pinkham’s M ini - L ab 3 Transparent, Translucent, and Opaque (and Dr. Pinkham’s Hip)

Transparent Transparent : allows light to pass through easily for a clear image.

Translucent Translucent : transmits some light, but does not let a clear image pass through.

Opaque Opaque : no light is allowed to pass through and no image can be seen through it. Things that are opaque create dark shadows when light shines on them.

opaque Nails are opaque. They do not allow X-rays to pass through. transparent Soft tissue is transparent. Most x-rays can pass through. translucent Bones are translucent. Some x- rays can pass through.

4 Dr. Pinkham’s M ini - L ab 4 The Broken Pencil and Magic Nickel

5 Dr. Pinkham’s M ini - L ab 5 Plane Mirrors: Reverse Images!

6 Dr. Pinkham’s M ini - L ab 6 Plane Mirrors: Reverse Images…backwards, too