Unit 9 Lesson 1: Light Waves

We’re going to take a deep look at the nature of light and its behavior during different types of experiments to try to figure out its properties. Light can travel through the vacuum of space as well as solid substances like glass. Energy exists as either matter or electromagnetic radiation.

Scientist are still trying to make heads or tails of this thing called light, and near as they can tell, it sometimes interacts like a particle (like a marble) and other like a wave (like on the ocean), and you really can’t separate the two because they actually complement each other.

Light can be either a wave or a particle, but not both at the same time. Which one it is will depend on what it’s doing. In this section, you’ll be able to figure out how intensity (how bright), frequency (wavelength), polarization (the direction of the electric field), and phase (time shift) all affect the kind of light you see and don’t see. Most light isn’t detectable by the human eye, which makes studying light more like investigating a crime scene. You’ll quickly be puzzling the pieces together to explain why pencils in a glass of water appear broken, why light beams can fry an egg, and how to build a telescope.

Scientific Concepts:

  • Light can travel through a vacuum, like space.
  • Light can change speeds, but the maximum speed is through a vacuum (186,282 miles per second).
  • Low frequency electromagnetic waves are called radio waves, which are not the same as sound waves.
  • Light you can see (visible light like a rainbow) makes up only a tiny bit of the entire electromagnetic spectrum.
  • Light has wavelength (frequency, or color), intensity (brightness), polarization (direction), and phase (time shift).
  • Prisms unmix light into its colors (wavelengths).
  • Light changes speeds when it passes through a different material (like water, glass, or fog).
  • Lenses work to bend light in a certain direction (refraction).
  • Concave lenses work to make objects smaller (door peep hole), convex lenses make them larger (magnifying lenses).


3 Polarizer Experiment
Shine a light through polarized sunglasses and the brightness decreases. If you hold two pairs of sunglasses one way, the light then is completely blocked! Not only that, but when you insert a third pair in between the two allows light to pass through again! Spooky! Materials Three pairs of polarized sunglasses (or three lenses […]
Science Teleclass: Light & Lasers & Holograms
This is a recording of a recent live teleclass I did with thousands of kids from all over the world. I’ve included it here so you can participate and learn, too! This class is all about Light Waves, Lasers and Holograms! This is a newly updated version of the older Light Waves and Lasers teleclass […]
Science Teleclass: Light & Lasers
This is a recording of a recent live teleclass I did with thousands of kids from all over the world. I’ve included it here so you can participate and learn, too! This class is all about Light Waves! Energy can take one of two forms: matter and light (called electromagnetic radiation). Light is energy in […]
Tech Light Lab Experiments
This set of experiments will show you the properties of light, including optics, diffraction, transmission, reflection, wavelength, intensity, and so much more. You’ll discover how light travels in a straight line, how light can turn a corner, split into several beams, and why objects can appear dark even when light is shining right on them.
Sky in a Jar
Have you ever wondered why the sky is blue? Or why the sunset is red? Or what color our sunset would be if we had a blue giant instead of a white star? This lab will answer those questions by showing how light is scattered by the atmosphere. Particles in the atmosphere determine the color […]
Optics, Fire, and Eyes
If you’ve never done this experiment, you have to give it a try! This activity will show you the REAL reason that you should never look at the sun through anything that has lenses in it. Because this activity involves fire, make sure you do this on a flame-proof surface and not your dining room […]
The Dark and Light of Polarization
Polarization has to do with the direction of the light.  Think of a white picket fence – the kind that has space between each board.  The light can pass through the gaps int the fence but are blocked by the boards.  That’s exactly what a polarizer does. When you have two polarizers, you can rotate […]
How to “See” Infra-Red Light
Crazy Remote Want to have some quick science fun with your TV remote? Then try this experiment next time you flip on the tube: Materials: metal frying pan or cookie sheet TV remote control plastic sheet
Light Tricks
When light rays strikes a surface, part of the beam passes through the surface and the rest reflects back, like a ball bouncing on the ground. Where it bounces depends on how you throw the ball. Have you ever looked into a pool of clear, still water and seen your own face? The surface of […]
Disappearing Beaker
We’re going to bend light to make objects disappear. You’ll need two glass containers (one that fits inside the other), and the smaller one MUST be Pyrex. It’s okay if your Pyrex glass has markings on the side. Use cooking oil such as canola oil, olive oil, or others to see which makes yours truly […]
Microscopes and Telescopes
Hans Lippershey was the first to peek through his invention of the refractor telescope in 1608, followed closely by Galileo (although Galileo used his telescope for astronomy and Lippershey’s was used for military purposes).  Their telescopes used both convex and concave lenses. A few years later, Kepler swung into the field and added his own […]
Spectrometers are used in chemistry and astronomy to measure light. In astronomy, we can find out about distant stars without ever traveling to them, because we can split the incoming light from the stars into their colors (or energies) and “read” what they are made up of (what gases they are burning) and thus determine […]
Pinhole Camera
This is the simplest form of camera – no film, no batteries, and no moving parts that can break. The biggest problem with this camera is that the inlet hole is so tiny that it lets in such a small amount of light and makes a faint image. If you make the hole larger, you […]
Mixing Cold Light
Here’s a trick question – can you make the color “yellow” with only red, green, and blue as your color palette?  If you’re a scientist, it’s not a problem.  But if you’re an artist, you’re in trouble already. The key is that we would be mixing light, not paint.  Mixing the three primary colors of […]
Measuring the Speed of Light with a Chocolate Bar
When you warm up leftovers, have you ever wondered why the microwave heats the food and not the plate? (Well, some plates, anyway.) It has to do with the way microwave ovens work. Microwave ovens use dielectric heating (or high frequency heating) to heat your food. Basically, the microwave oven shoots light beams that are […]
Rainbow Shadows
Imagine you’re a painter.  What three colors do you need to make up any color in the universe?  (You should be thinking: red, yellow, and blue… and yes, you are right if you’re thinking that the real primary colors are cyan, magenta, and yellow, but some folks still prefer to think of the primary colors […]
Light, Lasers, and Optics
When I was in grad school, I needed to use an optical bench to see invisible things. I was trying to ‘see’ the exhaust from a  new kind of F15 engine, because the aircraft acting the way it shouldn’t – when the pilot turned the controls 20o left, the plane only went 10o. My team […]
Benham’s Disk
Charles Benhamho (1895) created a toy top painted with the pattern (images on next page). When you spin the disk, arcs of color (called “pattern induced flicker colors”) show up around the disk. And different people see different colors! We can’t really say why this happens, but there are a few interesting theories. Your eyeball […]
Liquid Prism
In this experiment, water is our prism. A prism un-mixes light back into its original colors of red, green, and blue. You can make prisms out of glass, plastic, water, oil, or anything else you can think of that allows light to zip through. What’s a prism? Think  of a beam of light.  It zooms […]
In a simplest sense, a kaleidoscope is a tube lined with mirrors. Whether you leave the end opened or tape on a bag of beads is up to you, but the main idea is to provide enough of an optical illusion to wow your friends. Did you know that by changing the shape and size […]
Mixing Colors
There are three primary colors of light are red, green, and blue.  The three primary colors of paint are red, yellow, and blue (I know it’s actually cyan, yellow, and magenta, which we’ll get to in more detail later, but for now just stick with me and think of the primary colors of paint as red-yellow-blue […]
Ever play with a prism? When sunlight strikes the prism, it gets split into a rainbow of colors. Prisms un-mix the light into its different wavelengths (which you see as different colors). Diffraction gratings are tiny prisms stacked together. When light passes through a diffraction grating, it splits (diffracts) the light into several beams traveling […]
Black Light Treasure Hunt
Ever notice how BRIGHT your white t-shirt looks in direct sun? That’s because mom washed with fluorescent laundry soap (no kidding!). The soap manufacturers put in dyes that glow white under a UV light, which make your clothes appear whiter than they really are. Since light is a form of energy, in order for things […]
Advanced Telescope Building
So you’ve played with lenses, mirrors, and built an optical bench. Want to make a real telescope? In this experiment, you’ll build a Newtonian and a refractor telescope using your optical bench. Materials: optical bench index card or white wall two double-convex lenses concave mirror popsicle stick mirror paper clip flash light black garbage bag […]
Fun with UV
UV (ultra-violet) light is invisible, which means you need more than your naked eyeball to do experiments with it. Our sun gives off light in the UV. Too much exposure to the sun and you’ll get a sunburn from the UV rays. There are many different experiments you can do with UV detecting materials, such […]
Quantum Mechanics: Double Slit Experiment
This stuff is definitely sci-fi weird, and probably not appropriate for younger grades (although we did have a seven year old reiterate in his own words this exact phenomenon to a physics professor, so hey... anything possible! Which is why we've included it here.)
Advanced High School Course in Radio Astronomy
This experiment is for grades 9-12. Radio astronomy is the study of radio waves originating outside the Earth. The radio range of frequencies or wavelengths is loosely defined by three factors: atmospheric transparency, current technology, and fundamental limitations imposed by quantum noise.
Microwaving Soap
When you warm up leftovers, have you ever wondered why the microwave heats the food and not the plate? (Well, some plates, anyway.) It has to do with the way microwaves work.