Light Concepts
Initial perceptual naive misconceptions (any age)
Misconceptions
Light transmission
- Reflected light is shine or glare not something associated with seeing objects.
- Light can only do some of the following: be absorbed, blocked, reflected, or refracted by an object.
- Light is not reflected in a predictable manner and angle.
- Light is not refracted in a predictable manner and angle.
- The reflection of an object is located on the surface of the mirror. The reflection is often thought of as a picture on a flat or curved surface.
- To be seen in a mirror, the object must be directly in front of the mirror or within the line-of-sight from the observer to the mirror.
- Light always passes straight through transparent material (without changing direction).
- When an object is viewed through a transparent material, the object is seen exactly where it is located.
- Light only reflects from mirrors and shiny objects.
- If students are asked what helps you see? Most will answer glasses, seeing-eye dogs, binoculars, hand lenses, or microscopes, not light.
- Bright light travels further than dim.
- Light travels further at night.
- Light only travels a short way.
- Light stops.
Color
- White light is pure and colorless light.
- Color is a property of something other than a property of light.
- Sunlight is red, yellow, or orange
- Light travels from our eyes so we can see.
- Light eminates from the object being looked at (not a property of what light is reflected or absorbed).
- A prism or colored filter (piece of gel or plastic) puts color into light when it passes through it.
Sight
- Bats and owls can see in complete darkness.
- Humans can see in complete darkness after the eye adjusts. Students can persist with this belief by simply extending the time minutes, hours, days, years...
Shadows
- Shadows come from me. From other people or objects.
- Shadows follow you.
- Shadows come from clouds or the sky
- Shadows come from the sun as it shines on us and reflects off us to make a shadow.
Rainbows
- Sunlight reflects from rain
- Water sprinkler makes rainbows
- Bubbles make rainbows
- Mist, moisture in air causes rainbows
- Pot of gold
- Water falls through light. The water has color in it and when it hits the light you see it.
- When light hits falling rain it makes all the colors in the raindrops to reflect off one another and the colors that are the same come together.
Beginning (preschool - 7 years)
Concepts
- Light needs energy.
Intermediate (7 years - 11 years)
Concepts
- Light travels in a straight line until it strikes an object.
- Light can be reflected by a mirror, refracted by a lens, or absorbed by the object.
- Light interacts with matter by transmission (including refraction), absorption, or scattering (including reflection).
- To see an object, light is emitted by the object or reflected from its surface and enters the eye.
- Objects are seen only if they are illuminated by light interacting with them.
Literate (11+)
Concepts
- Light interference is when two waves mix. When waves meet or interfere the result will range from two crests or troughs combining to form a higher crest or lower trough, hence more intense or brighter light, to a crest and a trough combining to cancel each other, hence a less bright or intense light ranging from less light to dark. This can be observed in a double slit experiment when light, with the same wavelength, passes through the slits, the waves interfer with each other which can be projected onto a screen where the interference pattern can be seen as bands of light and dark.
- Diffraction is the spreading out of waves after light passes through a narrow gap.
- Refraction is the bending of light when it travels through different transparent mediums.
- Light is reflected at an angle proportional to the angle it strikes an object.
- Light is refracted at an angle related to the angle that it enters or leaves a medium and the density of the mediums. Color is a property of light.
- White light has all colors. Black is the absence of light and/or color. Computer code #000 or #000000 has a value of zero, hence black. Code #fff or #ffffff has the highest value, hence white. Check out base 16 for explanation of f having a number value.
- White light can be refracted to view a spectrum. Light is a form of energy that can be transfered or changed to other forms of energy.
- An electromagnetic wave model and a photon model explain features of electromagnetic radiation each describe some common applications of electromagnetic radiation.
Dr. Robert Sweetland's notes
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