Waves, sound, and light
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Refraction
Determine the angle of refraction for a light beam moving from one medium to another. The angle of incidence and each index of refraction … can be varied. Using the tools provided, the angle of refraction can be measured, and the wavelength and frequency of the waves in each substance can be compared as well.
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Basic Prism
Explore how a prism refracts light and investigate the factors that affect the amount of refraction. Shine white light or a single-color … beam through the prism. The index of refraction, prism width, prism angle, laser angle, and light wavelength can all be adjusted.
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Laser Reflection
Point a laser at a mirror and record the incoming angle as well as the angle after the reflection from the mirror. A protractor can be used … to measure the angles of incidence and reflection, and the angle of the mirror can be adjusted. A beam splitter can be used to split the beam, and non-ideal mirrors can be used.
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Ray Tracing (Lenses)
Experiment with a dynamic lens. Manipulate the position of an object and measure the distance and size of the image cast by a lens of … variable strength. Observe the focusing of various light rays emanating from the object.
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Ray Tracing (Mirrors)
Experiment with convex and concave mirrors. Manipulate the position of a light bulb and measure the distance and size of its image, formed … by the mirror. Learn the definition of focal point by observing the focusing of various light rays emanating from the bulb.
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Doppler Shift
Observe sound waves emitted from a moving vehicle. Measure the frequency of sound waves in front of and behind the vehicle as it … moves, illustrating the Doppler effect. The frequency of sound waves, speed of the source, and the speed of sound can all be manipulated. Motion of the vehicle can be linear, oscillating, or circular.
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Doppler Shift Advanced
Derive an equation to calculate the frequency of an oncoming sound source and a receding sound source. Also, calculate the Doppler shift … that results from a moving observer and a stationary sound source. The source velocity, sound velocity, observer velocity and sound frequency can all be manipulated.
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Longitudinal Waves
Observe the propagation of longitudinal (compression) waves in a closed or open tube with evenly-spaced dividers. The strength and … frequency of the waves can be manipulated, or waves can be observed as individual pulses. Compare the movement of dividers to graphs of displacement, velocity, acceleration and pressure.
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Phased Array
Observe the wave fronts produced by four closely-spaced emitters. The spacing and phase shift of each wave source can be adjusted, as well … as the wave velocity. With all four sources you can observe a region of constructive interference that moves over time. The phased array has several real world applications such as radar and ultrasound.
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Hearing: Frequency and Volume
Test your hearing range by listening to low-, medium-, and high-frequency sounds. Compare the relative loudness of sounds at each frequency … to create an equal-loudness curve. In a quiet room, measure your threshold of audibility for each frequency, and compare your results to others. The volume of each sound can be adjusted.
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Sound Beats and Sine Waves
Listen to and see interference patterns produced by sound waves with similar frequencies. Test your ability to distinguish and match sounds … as musicians do when they tune their instruments. Calculate the number of "sound beats" you will hear based on the frequency of each sound. [Note: Headphones are recommended for this Gizmo.]
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Additive Color v2
Control red, green, and blue spotlights (primary colors or RGB). Observe the additive colors as the spotlights overlap. The intensity of … the red, green, and blue lights can be adjusted, and the RGB value of the overlap region can be measured.
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Subtractive Color v2
Move spots of yellow, cyan, and magenta paint on a white surface. As the colors overlap, other colors can be seen due to color … subtraction. The color of most things you see, such as cars, leaves, paintings, houses and clothes, are due to color subtraction. The intensity of the cyan, magenta, and yellow can be adjusted, and the RGB values at any location can be measured.
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Herschel Experiment
Shine sunlight through a prism and measure the temperature in different regions of the spectrum using a thermometer wrapped in black tape. … The thermometer can be dragged throughout the entire spectral area and even beyond the visible light. This real‑world technique (developed by Friedrich Herschel in the 1700's) was used to investigate infrared light and, more recently, the spectrum of stars in our galaxy.
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Penumbra Effect
Observe how partial shadows are cast by multiple light sources. The number of light sources ranges from one to five, and lights can be … turned on or off. The distance and diameter of the shadow-casting object can be varied, and the light intensity can be seen on a detector.
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Photoelectric Effect
Shoot a beam of light at a metal plate in a virtual lab and observe the effect on surface electrons. The type of metal as well as … the frequency and intensity of the light can be adjusted. An electric field can be created to resist the electrons and measure their initial energies.
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Bohr Model: Introduction
Fire photons to determine the spectrum of a gas. Observe how an absorbed photon changes the orbit of an electron, and how a photon is … emitted from an excited electron. Calculate the energies of absorbed and emitted photons based on energy level diagrams. The light energy produced by the laser can be modulated, and a lamp can be used to view the entire absorption spectrum at once.
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Bohr Model of Hydrogen
Shoot a stream of photons through a container of hydrogen gas. Observe how photons of certain energies are absorbed, causing changes in … the orbits of electrons. Build the spectrum of hydrogen based on photons that are absorbed and emitted.
