Getting Started

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 times like a wave (like on the ocean), and you really can’t separate the two because they actually complement each other.

Energy can take one of two forms: matter and light (called electromagnetic radiation). Light is energy in the form of either a particle or a wave that can travel through space and some kinds of matter, like glass.

We’re going to investigate the wild world of the photon that has baffled scientists for over a century. Low electromagnetic radiation (called radio waves) can have wavelengths longer than a football field, while high-energy gamma rays can destroy living tissue.

Here are the scientific concepts:

  • 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).
  • Visible light is a small band within a very broad electromagnetic spectrum.
  • For an object to be seen, light emitted by or scattered from it must enter the eye.
  • Light travels in straight lines except when the medium it travels through changes.
  • How simple lenses are used in a magnifying glass, the eye, camera, telescope, and microscope.
  • White light is a mixture of many wavelengths (colors), and that retinal cells react differently with different wavelengths.
  • Light interacts with matter by transmission (including refraction), absorption, or scattering (including reflection).
  • The angle of reflection of a light beam is equal to the angle of incidence.
  • A simple wave has a repeating pattern with a specific wavelength, frequency, and amplitude.
  • A sound wave needs a medium through which it is transmitted.
  • When light shines on an object, it is reflected, absorbed, or transmitted through the object, depending on the object’s material and the frequency (color) of the light.
  • The path that light travels can be traced as straight lines, except at surfaces between different transparent materials (e.g., air and water, air and glass) where the light path bends.
  • A wave model of light is useful for explaining brightness, color, and the frequency-dependent bending of light at a surface between media.
  • However, because light can travel through space, it cannot be a matter wave, like sound or water waves.

By the end of the labs, students will be able to:

  • Design and build both a refractor and reflector telescope using lenses.
  • Show and describe a mathematical model for waves that shows how amplitude is related to the energy of a wave.
  • Develop an experiment that shows how waves are reflected, absorbed, and transmitted.
  • Know how to demonstrate how compound microscopes work.
  • Understand how to determine how to measure the speed of light.
  • Differentiate observation from inference (interpretation) and know scientists’ explanations come partly from what they observe and partly from how they interpret their observations.
  • Measure and estimate the weight, length and volume of objects.
  • Formulate and justify predictions based on cause-and-effect relationships.
  • Conduct multiple trials to test a prediction and draw conclusions about the relationships between predictions and results.
  • Construct and interpret graphs from measurements.
  • Follow a set of written instructions for a scientific investigation.

Select a Lesson

Laser Microscope
Did you know that you can use a laser to see tiny paramecia in pond water? We’re going to build a simple laser microscope that will shine through a single drop of water and project shadows on a wall or ceiling for us to study.
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 …Continue reading”Science Teleclass: Light & Lasers & Holograms”
Special Science Teleclass: Solar Astronomy
This is a recording of a recent live class I did with an entire high school astronomy class. I’ve included it here so you can participate and learn, too! Light is energy that can travel through space. How much energy light has determines what kind of wave it is. It can be visible light, x-ray, radio, …Continue reading”Special Science Teleclass: Solar Astronomy”
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 …Continue reading”Measuring the Speed of Light with a Chocolate Bar”
Electric Eye
This is a super-cool and ultra-simple circuit experiment that shows you how a CdS (cadmium sulfide cell) works. A CdS cell is a special kind of resistor called a photoresistor, which is sensitive to light. A resistor limits the amount of current (electricity) that flows through it, and since this one is light-sensitive, it will …Continue reading”Electric Eye”
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
Laser Maze
By using lenses and mirrors, you can bounce, shift, reflect, shatter, and split a laser beam. Since the laser beam is so narrow and focused, you’ll be able to see several reflections before it fades away from scatter. Make sure you complete the Laser Basics experiment first before working with this experiment. You’ll need to …Continue reading”Laser Maze”
Laser Microscope
Did you know that you can use a laser to see tiny paramecia in pond water? We’re going to build a simple laser microscope that will shine through a single drop of water and project shadows on a wall or ceiling for us to study.
Measure your Hair Width with a Laser
Do you have thick or thin hair? Let’s find out using a laser to measure the width of your hair and a little knowledge about diffraction properties of light. (Since were using lasers, make sure you’re not pointing a laser at anyone, any animal, or at a reflective surface.)
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.
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 …Continue reading”The Dark and Light of Polarization”
Spectrometer
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 …Continue reading”Spectrometer”
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 …Continue reading”Fun with UV”
Diffraction
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 …Continue reading”Diffraction”
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 …Continue reading”Light Tricks”
Eyeballoon
In this lab, we are going to make an eyeball model using a balloon. This experiment should give you a better idea of how your eyes work. The way your brain actually sees things is still a mystery, but using the balloon we can get a good working model of how light gets to your …Continue reading”Eyeballoon”
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 …Continue reading”Liquid Prism”
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 …Continue reading”Mixing Colors”
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 …Continue reading”Mixing Cold Light”
Fire & Optics
Today you get to concentrate light, specifically the heat, from the Sun into a very small area. Normally, the sunlight would have filled up the entire area of the lens, but you’re shrinking this down to the size of the dot. Magnifying lenses, telescopes, and microscopes use this idea to make objects appear different sizes …Continue reading”Fire & Optics”
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 …Continue reading”Black Light Treasure Hunt”
Laser Burglar Alarm
This is a beefier-version of the Electric Eye that will be be able to turn on a buzzer instead of a LED by increasing the voltage in the circuit. This type of circuit is a light-actuated circuit. When a beam of light hits the sensor (the “eye”), a buzzer sounds. Use this to indicate when …Continue reading”Laser Burglar Alarm”
Laser Light Show
What happens when you shine a laser beam onto a spinning mirror? In the Laser Maze experiment, the mirrors stayed put. What happens if you took one of those mirrors and moved it really fast? It turns out that a slightly off-set spinning mirror will make the laser dot on the wall spin in a …Continue reading”Laser Light Show”
Crystal Radio
In addition to laser experiments, I thought you’d like to learn how to pick up sound that’s traveling on a light wave. A crystal radio is among the simplest of radio receivers – there’s no battery or power source, and nearly no moving parts. The source of power comes directly from the radio waves (which …Continue reading”Crystal Radio”
Wave-Particle Duality of Light
Light acts like both a particle and a wave, but never both at the same time. But you need both of these concepts in order to fully describe how light works. Energy can take one of two forms: matter and light (called electromagnetic radiation). Light is energy in the form of either a particle (like …Continue reading”Wave-Particle Duality of Light”
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 …Continue reading”Light, Lasers, and Optics”
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 …Continue reading