The PhET project at the University of Colorado creates "fun, interactive, research-based simulations of physical phenomena." This particular one deals with Beer's Law. "The thicker the glass, the darker the brew, the less the light that passes through." Make colorful concentrated and dilute solutions and explore how much light they absorb and transmit using a virtual spectrophotometer! The simulation is also paired with a teachers' guide and related resources from PhET. The simulation is also available in multiple languages.

Explore bending of light between two media with different indices of refraction. See how changing from air to water to glass changes the bending angle. Play with prisms of different shapes and make rainbows.

Turn an old CD into a spectroscope to analyze light—you may be surprised by what you see. Try pointing your CD spectroscope at the fluorescent light in your room, sunlit clouds in the sky, even your friend’s colored shirt to reveal the wavelengths of light that mix together to create the color you see!

This lesson introduces the concepts of wavelength and amplitude in transverse waves. In the associated activity, students will use ropes and their bodies to investigate different wavelengths and amplitudes.

Make a whole rainbow by mixing red, green, and blue light. Change the wavelength of a monochromatic beam or filter white light. View the light as a solid beam, or see the individual photons.

In this video, David explains how Louis De Broglie got his Nobel Prize for the idea of matter having a wavelength.

Students find and calculate the angle that light is transmitted through a holographic diffraction grating using trigonometry. After finding this angle, student teams design and build their own spectrographs, researching and designing a ground- or space-based mission using their creation. At project end, teams present their findings to the class, as if they were making an engineering conference presentation. Student must have completed the associated Building a Fancy Spectrograph activity before attempting this activity.

Students are presented with a hypothetical scenario that delivers the unit's Grand Challenge Question: To apply an understanding of nanoparticles to treat, detect and protect against skin cancer. Towards finding a solution, they begin the research phase by investigating the first research question: What is electromagnetic energy? Students learn about the electromagnetic spectrum, ultraviolet radiation (including UVA, UVB and UVC rays), photon energy, the relationship between wave frequency and energy (c = λν), as well as about the Earth's ozone-layer protection and that nanoparticles are being used for medical applications. The lecture material also includes information on photo energy and the dual particle/wave model of light. Students complete a problem set to calculate frequency and energy.

Students are introduced to sound energy concepts and how engineers use sound energy. Through hands-on activities and demonstrations, students examine how we know sound exists by listening to and seeing sound waves. They learn to describe sound in terms of its pitch, volume and frequency. They explore how sound waves move through liquids, solids and gases. They also identify the different pitches and frequencies, and create high- and low-pitch sound waves.

In a hands-on way, students explore light's properties of absorption, reflection, transmission and refraction through various experimental stations within the classroom. To understand absorption, reflection and transmission, they shine flashlights on a number of preselected objects. To understand refraction, students create indoor rainbows. An understanding of the fundamental properties of light is essential to designing an invisible laser security system.

Students learn the basics of the electromagnetic spectrum and how various types of electromagnetic waves are related in terms of wavelength and energy. In addition, they are introduced to the various types of waves that make up the electromagnetic spectrum including, radio waves, ultraviolet waves, visible light and infrared waves. These topics help inform students before they turn to designing solutions to an overarching engineering challenge question.

To become familiar with the transfer of energy in the form of quantum, students perform flame tests, which is one way chemical engineers identify elements by observing the color emitted when placed in a flame. After calculating and then preparing specific molarity solutions of strontium chloride, copper II chloride and potassium chloride (good practice!), students observe the distinct colors each solution produces when placed in a flame, determine the visible light wavelength, and apply that data to identify the metal in a mystery solution. They also calculate the frequency of energy for the solutions.

Learn how to make waves of all different shapes by adding up sines or cosines. Make waves in space and time and measure their wavelengths and periods. See how changing the amplitudes of different harmonics changes the waves. Compare different mathematical expressions for your waves.

Learn how to make waves of all different shapes by adding up sines or cosines. Make waves in space and time and measure their wavelengths and periods. See how changing the amplitudes of different harmonics changes the waves. Compare different mathematical expressions for your waves.

Use the Sound Grapher to create visualizations of sound and learn about the frequency, wavelength, amplitude and velocity of sound waves.

Through an introduction to the design of lighting systems and the electromagnetic spectrum, students learn about the concept of daylighting as well as two types of light bulbs (lamps) often used in energy-efficient lighting design.

See how light knocks electrons off a metal target, and recreate the experiment that spawned the field of quantum mechanics.

See how light knocks electrons off a metal target, and recreate the experiment that spawned the field of quantum mechanics.

Sound is vibrating air. But how does the air start vibrating? Created by David SantoPietro.

Amplitude, period, frequency and wavelength of periodic waves. How to calculate wave velocity. Created by Sal Khan.