In this activity about light and perception, learners discover how a flash of light can create a lingering image called an "afterimage" on the retina of the eye. Learners will be surprised when they continue to see an image of a bright object after staring at it and looking away. Use this activity to introduce learners to principles of optics and perception as well as to explain why the full moon often appears larger when it is on the horizon than when it is overhead. This lesson guide also includes a few extensions like how to take "afterimage photographs."
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All biological cells require the transport of materials across the plasma membrane into and out of the cell. By infusing cubes of agar with a pH indicator, and then soaking the treated cubes in vinegar, you can model how diffusion occurs in cells. Then, by observing cubes of different sizes, you can discover why larger cells might need extra help to transport materials.
In this demonstration, amaze learners by performing simple tricks using mirrors. These tricks take advantage of how a mirror can reflect your right side so it appears to be your left side. To make the effect more dramatic, cover the mirror with a cloth, climb onto the table, straddle the mirror, and then drop the cloth as you appear to "take off." This resource contains information about how this trick was applied during the making of the movie "Star Wars."
In this simple exploration, a coiled phone cord slows the motion of a wave so you can see how a single pulse travels and what happens when two traveling wave pulses meet in the middle.
This webpage from Exploratorium provides an activity that demonstrates the Bernoulli principle with readily available materials. In this activity a table tennis ball is levitated in a stream of air from a vacuum cleaner. The site provides an explanation of what happens, asks questions about the activity, and also describes applications to flight. This activity is part of Exploratorium's Science Snacks series.
In this quick and simple activity, learners explore how the distribution of the mass of an object determines the position of its center of gravity, its angular momentum, and your ability to balance it. Learners discover it is easier to balance a wooden dowel on the tip of their fingers when a lump of clay is near the top of the stick. Use this activity to introduce learners to rotational inertia.
In this optics activity, learners discover that when they rotate a special black and white pattern called a Benham's Disk, it produces the illusion of colored rings. Learners experiment with the speed of rotation and direction of rotation to observe varying patterns. Use this activity to explain to learners how our eyes detect color and how different color receptors in the eye respond at different rates.
Demonstrate the Bernoulli Principle using simple materials on a small or large scale. This resource includes two activities that allow learners to experience the Bernoulli Principle, in which an object is suspended in air by blowing down on it. Use this activity to explain how atomizers work and why windows are sometimes sucked out of their frames as two trains rush past each other.
In this activity, a spinning bicycle wheel resists efforts to tilt it and point the axle in a new direction. Learners use the bicycle wheel like a giant gyroscope to explore angular momentum and torque. Learners can participate in the assembly of the Bicycle Wheel Gyro or use a preassembled unit to explore these concepts and go for an unexpected spin!
This activity provides instructions for using a flashlight and aquarium (or other container of water) to explain why the sky is blue and sunsets are red. When the white light from the sun shines through the earth's atmosphere, it collides with gas molecules with the blue light scattering more than the other colors, leaving a dominant yellow-orange hue to the transmitted light. The scattered light makes the sky blue; the transmitted light makes the sunset reddish orange. The section entitled What's Going On? explains this phenomena.
In this optics activity, learners examine how polarized light can reveal stress patterns in clear plastic. Learners place a fork between two pieces of polarizing material and induce stress by squeezing the tines together. Learners will observe the colored stress pattern in the image of the plastic that is projected onto a screen using an overhead projector. Learners rotate one of the polarizing filters to explore which orientations give the most dramatic color effects. This activity can be related to bones, as bones develop stress patterns from the loads imposed upon them every day.
In this activity, learners observe what happens when they give a light source like a neon glow lamp a "Bronx Cheer." The lights appear to wiggle back and forth and flicker when learners blow air through their lips. However, learners will discover that the only thing vibrating is themselves. Use this activity to explore different forms of light as well as visual perception.
In this activity, learners observe as soap bubbles float on a cushion of carbon dioxide gas. Learners blow bubbles into an aquarium filled with a slab of dry ice. Learners will be amazed as the bubbles hover on the denser layer of carbon dioxide gas, then begin to expand and sink before freezing on the dry ice. Use this activity to discuss sublimation, density, and osmosis as well as principles of buoyancy, semipermeability, and interference.