Physics of Light Review Sheet
Great job on our Physics of Light sessions this month! We’ve covered A LOT in a short amount of time, so I wanted to be sure you had a chance to really be impressed with the amount you’ve learned and how much understand about the world of physics!
Here’s what you can do now. First, I’ve put together a vocabulary list for you to review. If you’d like to, write each of these on an index card (make your own from sheets of paper). Don’t worry about the definitions just yet.
Next, let’s do a Spelling Bee! Grab a parent or sibling and ask them to test you on how to spell each one. If there are any that are just too hard (or too easy), remove them from the deck. If you’re the type of kid that has a lot of energy for movement, then you’ll like this tip: When I ask kids to spell words, I also have them bounce up and down on beds or trampolines or using a jump rope to really get them associated with the words.
Ready? Go ahead and work your way through this list.
Vocabulary:
Frequency Interference Coherence Concave lenses Convex lenses Radio waves Microwaves Infrared Visible light Ultraviolet (UV) X-rays Gamma rays Filters Intensity LASER Lenses Light Speed of Light Index of refraction Photoelectric effect Polarization Refraction Reflection Scattering Dispersion Wavelength Electromagnetic SpectrumPhysics of Light Review Sheet
Physics of Light Lab Practical
Now that you’ve got the words down, let’s see how much you really understand about each one. Instead of writing definitions (that will come later), let’s do a “Lab Practical”. This is how we’ll really get a sense of how much you understand and if there are any gaps.
Take your stack of words and hand them to someone else. (You can do this by yourself if you have to, but it’s a lot more fun to do this with a friend, a family member, or even as a “dinner show” after dinner that you can do for the family.
Now, when this person shows you a card, you have only a minute or two to demonstrate what that word actually means. In some cases, this will be easy, but in other cases, you may need to set up a quick experiment or sketch something out. Try to give three separate, different examples of each one.
The point is to think about how you would demonstrate to someone else about the word on the card, just like you were the teacher in the room. How would you explain it so they really understand? Go ahead and do this now for as many of these as you can.
Frequency Interference Coherence Concave lenses Convex lenses Radio waves Microwaves Infrared Visible light Ultraviolet (UV) X-rays Gamma rays Filters Intensity LASER Lenses Light Speed of Light Index of refraction Photoelectric effect Polarization Refraction Reflection Scattering Dispersion Wavelength Electromagnetic Spectrum
Physics of Light Review Sheet
Now it’s time to write actual definitions for each of these. I put together my slides for the month in this review sheet so you can refer to them if you need to. I am more interested in making sure you understand a concept and can explain it in to your own words rather than memorizing a definition I give you, so let’s see how you do before you peek at my slides. You can write the definitions below in the space provided (drawing pictures is perfectly fine also), or you can add them to the back of the cards you created back at the beginning.
Primary Colors of Light
_________________________________________________________________________ _________________________________________________________________________ Frequency _________________________________________________________________________ _________________________________________________________________________ Interference _________________________________________________________________________ _________________________________________________________________________ Coherence _________________________________________________________________________ _________________________________________________________________________
Physics of Light Review Sheet
Concave lenses _________________________________________________________________________ _________________________________________________________________________ Convex lenses _________________________________________________________________________ _________________________________________________________________________ Radio waves _________________________________________________________________________ _________________________________________________________________________ Microwaves _________________________________________________________________________ _________________________________________________________________________ Infrared _________________________________________________________________________ _________________________________________________________________________ Visible light _________________________________________________________________________Physics of Light Review Sheet
Ultra Violet (UV)
_________________________________________________________________________ _________________________________________________________________________ X-rays _________________________________________________________________________ _________________________________________________________________________ Gamma rays _________________________________________________________________________ _________________________________________________________________________ Filters _________________________________________________________________________ _________________________________________________________________________ Intensity _________________________________________________________________________ _________________________________________________________________________ LASER _________________________________________________________________________ _________________________________________________________________________
Physics of Light Review Sheet
Lenses _________________________________________________________________________ _________________________________________________________________________ Light _________________________________________________________________________ _________________________________________________________________________ Speed of Light _________________________________________________________________________ _________________________________________________________________________ Index of refraction _________________________________________________________________________ _________________________________________________________________________ Photoelectric effect _________________________________________________________________________ _________________________________________________________________________ Polarization _________________________________________________________________________Physics of Light Review Sheet
Refraction _________________________________________________________________________ _________________________________________________________________________ Reflection _________________________________________________________________________ _________________________________________________________________________ Scattering _________________________________________________________________________ _________________________________________________________________________ Dispersion _________________________________________________________________________ _________________________________________________________________________ Wavelength _________________________________________________________________________ _________________________________________________________________________ Electromagnetic Spectrum _________________________________________________________________________ _________________________________________________________________________Physics of Light Review Sheet
Electromagnetic waves are waves that can travel through space. Unlike sound waves (which require a medium in order to transport their energy), electromagnetic (light) waves are able to transport energy through the vacuum of space by vibrating electric charge. Electromagnetic waves have both an electric and magnetic component. The frequencies (wavelengths) these waves cover is called the electromagnetic spectrum (see next paragraph).
The amount of energy a photon has determines whether it’s a particle or a wave. Photons with the lowest amounts of energy and longest wavelengths (some are the size of football fields) are
radio waves. The next step up are microwaves, which have more energy than radio waves. IR
has slightly more energy, and visible light (the rainbow you can see with your eyes) has more energy and shorter wavelengths. Ultraviolet (UV) light has more energy than visible, and x-rays have even more energy than UV, x-rays are even higher energy and require special protection when working with this wavelength, and finally the deadly gamma rays have the most amount of energy.
Physics of Light Review Sheet
Definitions
The three primary colors of light are red, blue, and green. Red and green light mixed together make yellow light. Prisms un-mix light into its colors (wavelengths).
Concave lenses work to make objects smaller (door peep hole), and are curved inward like a cave.
Convex lenses make them larger (magnifying lenses), and have a ‘bump’ in the middle you can feel with your fingers.
Electromagnetic waves are waves that can travel through space. Unlike sound waves (which require a medium in order to transport their energy), electromagnetic (light) waves are able to transport energy through the vacuum of space by vibrating electric charge. Electromagnetic waves have both an electric and magnetic component. The frequencies (wavelengths) these waves cover is called the electromagnetic spectrum (see next paragraph).
The amount of energy a photon has determines whether it’s a particle or a wave. Photons with the lowest amounts of energy and longest wavelengths (some are the size of football fields) are
radio waves. The next step up are microwaves, which have more energy than radio waves. IR
has slightly more energy, and visible light (the rainbow you can see with your eyes) has more energy and shorter wavelengths. Ultraviolet (UV) light has more energy than visible, and x-rays have even more energy than UV, x-rays are even higher energy and require special protection when working with this wavelength, and finally the deadly gamma rays have the most amount of energy.
Filters can be used to block certain wavelengths.
Intensity, or brightness, is the amount of photons (packets of light) you have in a certain amount of space. A flashlight has less intensity than a car headlight.
LASER stands for Light Amplification by Stimulated Emission of Radiation. Most lasers are monochromatic (one color). Lasers are concentrated beams of light, and are illuminated by small particles (like smoke and dust).
Lenses work to bend light in a certain direction (refraction). A lens is a curved piece of glass or plastic that changes the speed of the light. Lenses have the same effect on lasers as on light beams.
Physics of Light Review Sheet
Light is energy that can travel through space. Light can be defined by four things: intensity (how bright), frequency (or wavelength), polarization (the direction of the electric field), and phase (time shift).
Objects can either be a light source (like the sun) or reflect light (like the moon).
Light can change speeds, but the maximum light speed is through a vacuum (186,000 miles per second). Light changes speeds when it passes through a different material (like water, glass, or fog).
Depending on the optical density of the material, light will bend by different amounts. Glass is optically denser than water. Water is more optically dense than air.
When two beams of light are out of phase with each other, it’s like playing a G and A on the piano. This is called phase shift.
Blue and UV light eject electrons from metal plates, but red light does not (photoelectric
effect).
Polarization has to do with the direction of the electric field. Your sunglasses are polarizing filters, meaning that they only let light of a certain direction in. The direction that the light is polarized has to do with the electromagnetic field.
When a beam of light hits a window, it bends and changes speed (refraction). Technically, the wavelength (color) changes but the frequency stays the same. In order for this to happen, the speed of light must also change.
Razor-edge slits create interference patterns. Slits are skinny holes that allow light to pass through. Scientists use slits to filter out all other light sources except the one they want to use in their experiment.
When you change the wavelength, you change the color of the light. The wavelength () equals the speed of light (c) divided by the frequency (), or = c / .