Unit 9 Module 2: Lasers – Supercharged Science

Lasers are super-cool gadgets that focus the light energy into a narrow beam you can tease cats and small kids with. Lasers first made their appearance in the 1960s, but had been thought about since the early 1900s by Einstein. We’re going to learn how to split, shatter, mix, bounce, gyrate, and spray laser light beams across our homemade lab bench. Are you ready?

The word "LASER" stands for Light Amplification by Stimulated Emission of Radiation. A laser is an optical light source that emits a concentrated beam of photons. Lasers are usually monochromatic – the light that shoots out is usually one wavelength and color, and is in a narrow beam. By contrast, light from a regular incandescent light bulb covers the entire spectrum as well as scatters all over the room. (Which is good, because could you light up a room with a narrow beam of light?).

Soon you'll be building shattering light rays, firing music on a laser beam, and building your own laser light show from tupperware. Let's get started by learning about lasers with this video:

ou can get started by watching this video, and afterward either read more about it or start your experiments!

Scientific Concepts:

LASER stands for Light Amplification by Stimulated Emission of Radiation.
Most lasers are monochromatic (one color).
Filters can be used to block certain wavelengths.
Razor-edge slits create interference patterns.
Laser beams are illuminated by small particles.
Lenses have the same effect on lasers as on light beams.
Lasers are concentrated beams of light.
When a laser is aimed at a window, part of the beam passes through while the rest is reflected back.
Aiming a laser on a spinning mirror changes the position of the laser beam reflection.

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	What is a Laser? Have you ever wondered why you just can’t just shine a flashlight through a lens and call it a laser? It’s because of the way a laser generates light in the first place.The word LASER is an acronym for Light Amplification by Stimulated Emission of Radiation.That’s a mouthful. Let's break it down.Let's do an experiment … Continue reading "What is a Laser?"
	Laser Safety Most people know not to shine lasers into sensitive places like eyeballs, but very few people can tell one laser from another. The truth is that not ALL lasers are dangerous, and there are different classifications of lasers. The most important information you need about laser safety is printed right on the laser itself. Basic … Continue reading "Laser Safety"
	Laser Basics Did you know that the word LASER stands for Light Amplification by Stimulated Emission of Radiation? And that a MASER is a laser beam with wavelengths in the microwave part of the spectrum? Most lasers fire a monochromatic (one color) narrow, focused beam of light, but more complex lasers emit a broad range of wavelengths … Continue reading "Laser Basics"
	Laser Collimation Laser light is collimated, meaning that it travels in parallel rays. Here’s a really cool experiment that will show you the difference between a non-collimated light, like from a flashlight and collimated light from a laser. Ordinary light from a light bulb diverges as it travels. It spreads out and covers a larger and larger … Continue reading "Laser Collimation"
	Laser Coherence Lasers light is different from light from a flashlight in a couple of different ways. Laser light is monochromatic, meaning that it’s only one color. Laser light is also coherent, which means that the light is all in synch with each other, like soldiers marching in step together. Since laser light is coherent, which means … Continue reading "Laser Coherence"
	Reflection Law using a Laser The angle that the reflected light makes with a line perpendicular to to the mirror is always equal to the angle of the incident ray for a plane (2-dimensional) surface. We’re going to play with how light reflects off surfaces. At what angle does the light get reflected? This experiment will show you how to … Continue reading "Reflection Law using a Laser"
	Refraction using Lasers and Water This simple activity has surprising results! We’re going to bend light using plain water. Light bends when it travels from one medium to another, like going from air to a window, or from a window to water. Each time it travels to a new medium, it bends, or refracts. When light refracts, it changes speed … Continue reading "Refraction using Lasers and Water"
	Lasers, Jell-O and Trigonometry If you’re scratching your head during math class, wondering what you’ll ever use this stuff for, here’s a cool experiment that shows you how scientists use math to figure out the optical density of objects, called the “index of refraction”. How much light bends as it goes through one medium to another depends on the … Continue reading "Lasers, Jell-O and Trigonometry"
	Gummy Bears, Absorption, and Transmittance Gummy bears are a great way to bust one of the common misconceptions about light reflection. The misconception is this: most students think that color is a property of matter, for example if I place shiny red apple of a sheet of paper in the sun, you’ll see a red glow on the paper around … Continue reading "Gummy Bears, Absorption, and Transmittance"
	Fluorescence Fluorescent minerals emit light when exposed to ultraviolet (UV) light, usually in a completely different color than when exposed to white light. UV is invisible to the human eye, and is the wavelength of light that is responsible for sunburns.
	Measuring the Wavelength of a Laser Diffraction is how light bends as it passes through very narrow slits or around very thin objects like a hair. When light travels around a hair, two wave patterns form, and those waves interfere with each other constructively (they add together to form a bright region) or destructively (the cancel each other out and leave … Continue reading "Measuring the Wavelength of a Laser"
	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.)
	Measure the Track Spacing of a DVD and CD We’re going to use a laser pointer and a protractor to measure the microscopic spacing of the data tracks on a DVD and a CD. The really cool part is that you’re going to use an interference pattern to measure the spacing of the tracks, something that you can’t normally see with your eyes. Interference … Continue reading "Measure the Track Spacing of a DVD and CD"
	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 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"
	Space-Age Laser Communicator This experiment is for advanced students.Did you know that when you talk inside a house, the windows vibrate very slightly from your voice? If you stand outside the house and aim a laser beam at the window, you can pick up the vibrations in the window and actually hear the conversation inside the house. Remember … Continue reading "Space-Age Laser Communicator"

Scientific Concepts:

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