This is a resource from the Digital Library at San Francisco's Exploratorium. Kid-friendly experiments and explorations for curious minds.
- 10/02 - Diamagnetism Activity: This activity provides instructions for demonstrating diamagnetism using a grape and a strong rare-earth magnet. Diamagnetic materials, such as water, are repelled by both poles of a magnet. Diamagnetic materials are repelled by magnetic poles. Water is a diamagnetic substance. This behavior is predicted by a law of physics known as Lenz's Law. This law states that when a current is induced by a change in magnetic field (the orbital currents in the grape created by the magnet approaching the grape), the magnetic field produced by the induced current will oppose the change.
- 9/25 - Colored Shadows Activity: This activity provides instructions for building red, blue, and green spotlights that combine to produce white light and cyan, magenta, and yellow shadows. The retina of the human eye has three receptors for colored light. When a red light, a blue light, and a green light are all shining on the screen, the screen looks white because these three colored lights stimulate all three color receptors on your retinas approximately equally, stimulating the sensation of white. With these three lights you can make shadows of seven different colors.
- 9/18 - Resonator Activity: In this activity, wooden dowels of varying lengths, each loaded with the same mass, are vibrated (by hand) at identical frequencies. When the frequency of vibration matches the resonant frequency of one of the dowels, that dowel vibrates with a very large amplitude. If you vibrate an object near one of its natural, or resonant, frequencies, its motion may grow dramatically, a process known as resonance. Spectacular examples of resonance include the collapse of the Tacoma Narrows Bridge in the state of Washington during a windstorm, and the destruction of buildings during earthquakes.
- 9/11 - Fog Chamber Activity: This activity provides instructions for making fog appear inside a glass jar. form when invisible water vapor in the air is cooled enough to form tiny droplets of liquid water. In the atmosphere, this usually happens when moist air cools as it rises to higher altitudes. At higher altitudes the pressure is lower, so the gas expands, loses internal energy, and cools.
- 9/04 - Flipsticks Make-it-yourself Cartoon Kit: This activity provides instructions and images for making your own animated cartoons. When you look at a picture, then quickly flip to another picture, your eye and brain remember the first picture for a fraction of a second, and blend it with the second picture. This visual ability, known as persistence of vision, makes the pictures in movies appear to move.
- 8/28 - Making a Sun Clock Activity: This activity provides instructions for using shadows to tell the time. Shadows change direction, depending upon the time of day. A Sun Clock like this one uses a shadow's position to tell the time.
- 8/21 - Up Periscope! Activity: This activity provides instructions for building a mirrored tube that lets you see around corners and over walls. Light always reflects away from a mirror at the same angle that it hits the mirror. In your periscope, light hits the top mirror at a 45-degree angle and reflects away at the same angle, which bounces it down to the bottom mirror. That reflected light hits the second mirror at a 45-degree angle and reflects away at the same angle, right into your eye.
- 8/14 - Pringles Pinhole Activity: This activity provides instructions for recycling a potato chip can into a simple camera. How does a hole in the bottom of a Pringles(r) can make a picture of the world? The hole doesn't make the picture. The image of the world is always there. All the hole does is make it possible for you to see it. provides instructions for recycling a potato chip can into a simple camera.
- 8/07 - File Card Bridges Activity: This activity provides instructions for building bridges using file cards and then measuring their strength in pennyweights. How many pennies will your bridge hold? You may find that a file-card bridge can hold more pennies than you'd think! Using file cards, you can make two of the three (beam and arch) different kinds of bridges.
- 7/31 - Modeling the Seasons: This activity provides instructions for students to model the seasons with their own earth globes. After students have been to each of the four dates: December 21, March 21, June 21, and September 21, they will have modeled a year, or one earth revolution around the sun. Includes "Teacher Tips."
- 7/24 - Three Little Pig (ments). Know your C,Y, M and K: This activity provides instructions for investigating how light and color interact by aligning three colored and one black overhead transparencies. Although white light contains a rainbow of colors, our eyes are only sensitive to red (R), green (G) and blue (B) light. Your brain takes the stimuli from those three colors and interprets all the other colors based on the proportion of RGB. Since human brains only process those three colors of light, white light can be effectively described as a combination of RGB. The combinations of two of the three primary colors of light produce the secondary colors of light.
- 7/17 - Electroscope Activity: This activity provides instructions for building an electroscope, a device that detects electrical charge, using drinking straws and plastic tape. Negative charges can move, positive charges remain stationary. An object can become charged by moving electrons. Like charged objects repell, objects with unlike charges attract each other.
- 7/10 - Welcome to the 3rd Dimension Activity: This activity provides instructions for viewing 3-dimensional images that appear to shift and change as you look at them. Psychologists have two theories about why pictures like these appear to flip back and forth. The first is that it depends on shifting your gaze from one part of the picture to another to make the picture flip. The other theory is that your brain gets tired of looking at it one way and switches to the other to give itself a break.
- 7/03 - Vocal Vowels Online Exhibit, In Spanish: This online exhibit shows—with sound clips—how changing the shape of the resonating chamber changes a sound. You can click on resonating chambers of various shapes to hear the squawk of a duck call being shaped into the vowels of English.
- 6/26 - Science of Music Web Site: This sound-rich Web site explores the science of music, starting with the existential question: "Why does my voice sound so good in the shower?" The physics of how shower walls alter sound waves to affect volume, reverb, and bass boost is explained. Another big question: "Why does some music give me the goose bumps?" introduces the neurobiology of our emotional response to music. Other parts of the site look into the historical background of various extraordinary instruments such as the steel drum and the jembe.
- 6/19 - Jumping to Conclusions and Who Goes There Activities: These two activities—"Jumping to Conclusions" and "Who Goes There" provide instructions for making confusing messages using the top half of letters and asking a friend to read the message. You only see part of each letter of a word, but your brain looks for a pattern and fills in the missing pieces. Because your brain tries to make sense of the word, it completes the letters to produce familiar words.
- 6/12 - Fruitful DNA Extraction Activity: This activity provides instructions for extracting DNA from kiwi fruit using simple household chemicals. The procedure used in this activity has the same essential elements as more advanced laboratory DNA extraction procedures: mechanical and thermal disruption of cells, liberation of the DNA, and precipitation of the DNA.
- 6/05 - Earthquake Activities: There are four easy-to-build, inexpensive, hands-on activities that demonstrate various aspects of earthquake science and plate tectonics. The "cookie subduction" activity uses a cream-filled cookie to demonstrate subduction and accretion. The "highway seismograph" lets you model the workings of a real seismograph as you record a bumpy car ride. "Seismic Slinky" demonstrates different patterns of seismic waves that spread an earthquake's destructive energy. "Liquefaction" demonstrates how some soils, such as landfill, lose their solidity in an earthquake.
- 5/29 - Do Your Own Image Walk: This activity provides instructions for creating and using simple materials (cards you can make yourself, the lens of a magnifying glass, and a mirror) to go on an Image Walk. It will change the way you look at light, shadow, and images.
- 5/22 - Depth Spinner Online Exhibit: This exhibit directs you to look at a spinning spiral that appears to be advancing or receding for 30 seconds, and then look at a stationary object such as a wall. The wall will appear to be moving in the direction that's opposite to the spiral's motion. After you watch the spiral for 30 seconds, the receptors in your eyes that detect inward motion (or outward motion, depending on which way the spiral is spinning) adapt and stop responding. The receptors that that detect motion in the opposite direction briefly override them, so you see motion in that direction. This exhibit challenges students to analyze what they are seeing and question whether their perceptions are accurate. Scientists study illusions and the way the visual system perceives them to examine human perception and the workings of the brain.
- 5/15 - Continental Drift Animation: The animation (in Flash and non-Flash versions) shows the supercontinent Pangaea ("all lands") fragmenting into the continents that exist today. Short text passages present some of the evidence that supports the theory of continental drift. The theory of plate tectonics—that the outermost layer of the earth consists of about a dozen plates (large slabs of rock) moving around on the molten mantle beneath them—grew out of the theory of continental drift.
- 5/08 - Common Cents Online Exhibit: This online exhibit asks you to select the correct image of an American penny from a bank of twelve images that look like a penny, eleven of which have minor changes in the details of their design. The exhibit, which has counters showing how many people select each image, shows that most people don't keep track of the details of the penny's design. People need enough information to be able to recognize a penny when they see one. But they don't need to remember the many details of the penny's design to distinguish it from a dime or quarter. This sort of experiment suggests that people are likely to remember only enough visual information about an object to let them recognize it in everyday life.
- 5/01 - Build a Bacterial Terrarium: This activity provides instructions for growing colonies of multi-hued microbes in a clear tennis ball can with just mud, paper and an egg. Some bacteria are photosynthetic. Blue-green bacteria near the top of the mud column use light, carbon from carbon dioxide, and hydrogen from water to make carbohydrates and give off oxygen. Other bacteria are decomposers producing carbon dioxide and using all the oxygen near the bottom of the container. In this oxygen free region live colorful photosynthetic bacteria which use hydrogen sulfide as their hydrogen source for photosynthesis.
- 4/24 - Bird in a Cage Online Exhibit, In Spanish: This is an online version of the famous "bird-in-a-cage" illusion caused by a lingering afterimage. An additional image creates a "stars-and-stripes" illusion, illustrating the same effect. You stare for 20 seconds at a bird of a particular color outside a cage. Then, when you look at the empty cage, a shadowy image of a bird of a complementary color appears inside the cage.
- 4/17 - Bernoulli Levitator Activity: The Bernoulli principle explains how atomizers work and why windows are sometimes sucked out of their frames as two trains rush past each other. You can choose from two versions of this activity—small or large.
- 04/10 - Which Languages are Related?: This activity provides instructions for discovering which languages belong to a common family.
- 04/03 - Tic Tac Toe Activity: Provides instructions and tricks for winning Tic-Tac-Toe strategies. This game isn't quite as simple as you think.
- 03/27 - Straws and Pins—Building Out Activity: This activity provides instructions for building out with straws and pins. It offers students the opportunity to experience many of the basic physics and engineering concepts inherent in structures. Illustrates inquiry skills and investigates building support strength, stability and durability.
- 03/18 - Skewers and Garden Pole Activity: This activity provides instructions for building on two scales to see clear examples of how some relationships of physical properties change with scale and others remain the same.
- 03/11 - Pinhole Projector Activity: This activity provides instructions for safely viewing a solar eclipse through a box pinhole projector, a hole in cardboard, or your fingers.
- 03/04 - Paper Airplanes Activity: This activity provides instructions for building a sophisticated paper airplane.
- 02/26 - Newspaper Bridges Activity: This activity provides instructions for challenging students to build the biggest, strongest bridge possible from newspaper and tape. It is necessary to build, test and modify engineering designs in order to produce structures of optimal strength.
- 02/19 - Memory Solitaire and Tell Yourself a Story Activities: These two activities—"Memory Solitaire" and "Tell Yourself a Story" provide instructions for helping you develop memory.
- 02/12 - Memory Party Game: This activity provides instructions for playing a game that tests your memory. Play this game with a group of people and compare your memory to theirs.
- 02/05 - Mayan Math Activity: In this activity, you'll begin to decode the Mayan number system as it's written in a document known as the "Dresden Codex." The Maya developed a sophisticated number system that they used to record possessions, dates, and astronomical observations. Includes "Teachers Guide."
- 01/29 - Mayan Calendar Round: Keeping Time: This activity provides instructions for determining the common New Year's Days of the two Mayan calendars using gears or least common multiples. The Maya had two calendars—one was tied to the astronomical year, and had 365 days like ours. The other was shorter, 260 days, and was associated with rituals. Includes "Teachers Guide."
- 01/22 - Making Naked Eggs: This activity includes directions for using vinegar to dissolve an eggshell without breaking the membrane that contains the egg. Egg shells, made of calcium carbonate, react with acetic acid, vinegar, to produce bubbles of carbon dioxide and release calcium ions into the solution dissolving the egg shell. The membrane containing the egg is not affected by the acid.
- 01/15 - Lightning in Your Mouth Activity: This activity illustrates how crunching on a wintergreen LifeSaver® makes a miniature lightning storm in your mouth. When you crush sugar crystals, the stress in the crystal creates electric fields. These electric fields rip the outer electrons from molecules. When the molecules recombine with their electrons, they emit light. In addition to blue and violet light, the crunched crystals produce ultraviolet light, which you can't see. Wintergreen oil converts ultraviolet light into visible blue light, making the light you can see brighter.
- 01/08 - Jumping to Conclusions and Who Goes There Activities: These two activities provide instructions for making confusing messages using the top half of letters and asking a friend to read the message. You only see part of each letter of a word, but your brain looks for a pattern and fills in the missing pieces. Because your brain tries to make sense of the word, it completes the letters to produce familiar words.
- 01/01 - How to Build a Spectroscope Activity: This activity will take you through the process of making your own spectroscope step-by-step. Using a spectroscope, you can see that a single color of light is really comprised of a combination of colors, called a spectrum. A spectroscope enables you to see and compare the spectra produced by different light sources.
- 12/25 - Handmade Paper Activity: This activity provides instructions for making handmade paper from recycled paper. As you make your own paper, you'll observe the water and energy required to reprocess paper fiber. In commercial manufacturing, producing printing grade recycled paper can save as much as half the energy that's needed in making paper from wood pulp, and there's a savings of water as well.
- 12/18 - Global Climate Change: Research Explorer: At this Web site, you can find real-time scientific data and research relating to the atmosphere, the oceans, the areas covered by ice and snow, and the living organisms in all these domains. See how researchers gather evidence, test theories, and come to conclusions.
- 12/11 - Geodesic Gumdrops Activity: This activity provides instructions for making amazing architecture with candy and toothpicks, and illustrate structural strength, compression, tension, and forces on structures.
- 12/04 - Garden Poles—Building Out Activity: This activity provides instructions for building out with garden poles and tape. Change on a larger scale makes materials seem more flimsy and joints seem less secure. It also provides students with the opportunity to experience basic physics and engineering phenomena.
- 11/27 - Fantastic Four Activity: This activity uses four randomly selected numbers to create an equation that equals a fifth number. It gives people a chance to practice different mathematical operations and to practice writing equations correctly. Includes separate teacher/leader version link at bottom of page.
- 11/20 - El Niño: Early Warning: This Web site reports on a conference concerning early predictions of El Niño held on the Galapagos Islands. Along with dispatches from the conference, twenty hours of audio presentations are included. Images of the islands and the animals that inhabit them are scattered throughout and in a slide show.
- 11/13 - Double Trouble Activity: This activity provides instructions for seeing a second hidden image buried in one that is easier to see. Sometimes, there are two completely different ways to look at the same thing. When a picture doesn't give you enough information to decide how to view it, your brain has to make a choice.
- 11/06 - Dime Tic-Tac-Toe Activity: This activity provides instructions for a more complicated version of the classic game Tic-Tac-Toe. Unlike classic Tic-Tac-Toe, in this version you can move around the coins (used in place of O and X) once you've put them down. However, there are strict rules for coin movement. Learn strategies to win.
- 10/30 - Cylinders and Scale Activity: Using a film canister and paper products, explore the relationship of increasing length, area and volume of cylinders. Students need to see the patterns of scaled growth in different shapes before they can understand the universality of scaling patterns.
- 10/23 - Cold Boiling Water Activity: In this activity, you'll create a vacuum by covering the end of a syringe containing water and then pulling on the plunger. This lowers the pressure and makes the water bubble like a hot pot on the stove.
- 10/16 - Clay Bridges Activity: Students explore the effects of gravity and weight on horizontal structures. In building bridges, students can observe the effects of the weight of structure itself, as well as tension and compression and other forces acting on the structure.
- 10/09 - Bubbularium Activity: The activity gives directions for building a bubble dome from simple materials—a clear plastic lid, a straw, bubble solution, a flashlight, and tape. This inexpensive bubblarium allows a close-up observation of iridescent bubble colors.
- 10/02 - Become a Word Historian: This activity provides instructions for using an ordinary dictionary to find extraordinary histories of words. Many English words have their origins in other languages. By finding words with similar sounds and meanings in other languages, it's often possible to trace the history of a word back through many centuries.
- 09/25 - Amazing Water Trick Activity: In this activity, students discover that hot water (tinted with food coloring) will flow upward and mix with cold water above it. If a layer of cold water is beneath a layer of hot water, however, no mixing will occur.
- 09/18 - A Cell's Fate: Learn how the single cell of a fertilized egg develops into a human embryo. In particular, it describes the class of cells known as stem cells. Stem cells have two features that make them unlike any other cell: They can make identical copies of themselves, and they can make differentiated-specialized-cells such as nerve cells or muscle cells. The article also discusses differences between two kinds of stem cells-embryonic and adult.
- 09/11 - Cafe Wall Illusion Online Exhibit (in Spanish): In this online exhibit, the straight lines of grout in a tile wall can appear to curve. The interactive exhibit lets you move the rows of tiles and change the color of the grout to find when the effect appears. The illusion of curved lines appears only when the rows of tiles are offset and when the grout is gray, rather than black or white. The exhibit illustrates the limitations of perception, and the limitations on the way the brain interprets data perceived by the eyes.
- 09/04 - Vocal Vowels Online Exhibit (in Spanish): This online exhibit shows—with sound clips—how changing the shape of the resonating chamber changes a sound. You can click on resonating chambers of various shapes to hear the squawk of a duck call being shaped into the vowels of English.
- 08/28 - Fading Dot Online Exhibit (in Spanish): This online exhibit is a visual illusion in which a fuzzy blue dot disappears into a green background. You remain completely still and stare directly at the fuzzy pale blue dot. The dot gradually disappears, apparently becoming green. This exhibit demonstrates that the eyes, by making tiny jittering movements, are constantly receiving new information to send to the brain. The color changes at the edge of the fuzzy dot are so gradual that the eye can't tell the difference between one point and the point right next to it. So the eyes—even thought they're moving—receive no new information, and the fuzzy blue dot seems to fade away. If the dot had a distinct border, the eyes would continue to receive new information and be able to detect the border between the colors.
- 08/21 - Mona Online Exhibit (in Spanish): This online exhibit shows two upside-down Mona Lisas, one with her eyes and mouth inverted. Our eyes read the familiar paintings in the unfamiliar position as having unaltered faces, until we see them right-side up, when we can see the grotesque alterations. The exhibit includes a suggested activity of creating the same illusion with photos of other faces.
- 08/14 - Bird in a Cage Online Exhibit (in Spanish): This is an online version of the famous "bird-in-a-cage" illusion caused by a lingering afterimage. An additional image creates a "stars-and-stripes" illusion, illustrating the same effect. You stare for 20 seconds at a bird of a particular color outside a cage. Then, when you look at the empty cage, a shadowy image of a bird of a complementary color appears inside the cage. You see color when receptor cells (called cones) on your eye's retina are stimulated by light. There are three types of cones, each sensitive to a particular color range. If one or more of the three types of cones becomes adapted to a particular color, when you look away, you will perceive an afterimage of the same object in its complementary color.
- 08/07 - Shimmer Online Exhibit (in Spanish): This online exhibit is an optical illusion composed of black and white lines radiating from a center point. As you look steadily at it, the array of black and white lines creates the impression of shimmering movement. The motion that you see is not in the exhibit but in your own eye. Even though you're not aware of it, your eyes are constantly making small, jittering movements, which continually refresh the image cast on the back of your eye. Normally, your brain can ignore this motion, so your picture of the world stays stable. But with this illusion, the new images are similar but not exactly the same as the old, which creates the shimmering effect.
- 07/31 - Postcard Online Exhibits (in Spanish): This online exhibit presents four optical illusions—each small enough to be illustrated on a postcard. One is a drawing that can be a young lady or an old woman, depending on your perception. A set of silhouettes can be vases or faces, depending on whether you focus on the light or the dark sections. One requires that you say out loud the color of ink various color words are printed in—showing how influential the written word can be over other visual cues. The fourth is an experiment with disappearing dots.
- 07/24 - Changing Illusions Online Exhibit (in Spanish): This online exhibit contains five interactive visual illusions. They demonstrate how hard it is to be sure that one's perceptions are accurate. These visual illusions challenge students to analyze what they are seeing. The visual paradoxes they find are used to study visual perception and the workings of the brain. The exhibit points out that scientists are fascinated by illusions because, by figuring out how the eye and brain can be tricked, they can better understand the normal workings of the visual system.
- 07/17 - Depth Spinner Online Exhibit (in Spanish): This exhibit directs you to look at a spinning spiral that appears to be advancing or receding for 30 seconds, and then look at a stationary object such as a wall. The wall will appear to be moving in the direction that's opposite to the spiral's motion. After you watch the spiral for 30 seconds, the receptors in your eyes that detect inward motion (or outward motion, depending on which way the spiral is spinning) adapt and stop responding. The receptors that that detect motion in the opposite direction briefly override them, so you see motion in that direction.
- 07/10 - Take It From the Top "Snack": This activity (aka "snack") provides instructions for "defying gravity" by stacking wooden blocks (or textbooks) so that the top block extends completely past the end of the bottom block.
- 07/03 - Seismic Slinky Activity: This activity uses a Slinky to illustrate the different kinds of waves that transmit the energy of an earthquake outward from its focus.This easy activity serves as an introduction to P and S waves and how they transmit a quake's destructive energy from its focus within the earth. You can also demonstrate the action of Rayleigh and Love waves, seismic waves that travel near the surface of the earth.
- 06/26 - Proprioception "Snack": This activity (aka "snack") provides instructions for observing your sense of body position—where your legs and arms are, for example—even with your eyes closed. Since most of us are highly dependent on visual cues for judging distance, position, etc. proprioception alone is not enough to give us the fine detail of position.
- 06/19 - Stuff of Life: This resource focuses on cells as the essence of life itself. This Web page provides links to four pages that allow exploration of cells. You can explore the inner working so a cell with "The Cell Explorer," a set of interactive exhibits. You can download a pdf of a poster showing how your muscles contract. An interview with scientist/artist David Goodsell points out connections between art and science. An article discusses stem cells and their unique characteristics.
- 06/12 - Your Weight on Other Worlds Activity: This interactive activity allows earthlings to calculate their weights on other planets. You type in your weight, in whatever unit you wish, and your weight in that unit is calculated for all the planets—and a number of other celestial bodies, such as the moons of Jupiter and different types of stars.
- 06/05 - Your Age on Other Worlds Activity: This interactive activity allows earthlings to calculate their ages on other planets, counted in the other planets' days and years. You type in your birthday, and the site calculates your age in days and years for the other planets of the solar system. As a bonus, your next birthday is shown for all the planets.
- 05/29 - Squirming Palm Online Exhibit: At this online exhibit, you look at a rotating disk of dots for 15 seconds, and then look at your own palm. Your palm will appear to be moving in the opposite direction from the way the disk was spinning. This is a variation of a well-known illusion called the "waterfall effect" in which you see upward motion after staring at the downward motion of a waterfall.
- 05/22 - Microscope Imaging Station Web Site: This video-rich Web site makes available a wide array of magnified images captured by microscope. Numerous videos illustrate microscopic processes such as cell division by mitosis, embryonic development, immune response by white blood cells, and zygotes uniting as fertilization takes place. The gallery includes still and video images of white and red blood cells, stem cells, roundworms (C. elegans), mouse embryonic cells, amoebae, protozoa, plankton, fruit flies, sea urchins, leaf cells, and zebrafish. The images and accompanying text explore cellular structure and function.
- 05/15 - Science of Gardening Web Site: This rich Web site explores many aspects of the science of gardening, including soil chemistry, the history of domesticated plants, the many ways plants propagate, and how plants are bred for desired characteristics. Nitrogen-fixing bacteria are discussed, as well as why a soil's pH matters, and the symbiotic relationship between fungi and some plants is explored. Biodiversity and the seed collecting that helps preserve it is touched upon.
- 05/08 - Science of Baseball Web Site: This Web site describes the science of baseball, such as the aerodynamics of pitching fastballs, curveballs, screwballs, and sliders. Also described is the neurobiology behind the rapid-fire perception and response—measured in thousandths of a second—required of the hitter. The materials and construction used in bats, balls, and gloves are explored, and changes over the years, responding to advances in materials science and players' experimentation with design and materials, are tracked.
- 05/01 - Frogs: This Web site, based on a popular exhibition, explores the adaptable frog—and the importance of frogs as research animals and environmental sentinels—through articles, audio, video, and interactive exhibits.
- 04/24 - Chaco Canyon: This Web site explores Chaco Canyon, NM, an ancient astronomical observatory. The architecture of the ancient Chacoans aligns with the solstices and other events of the sun. Maps, images, history, animations, interviews, activities, and a Webcast link the past and present.
- 04/17 - Chichen Itza: This Web site explores Chichen Itza, home to the ancient Maya, and looks at their understanding of astronomical events, particularly the equinox. Maps, images, interviews, history, activities, and a Webcast in both Spanish and English link the past and present.
- 04/10 - Stripped Down Motor "Snack": This activity (aka "snack") provides instructions for a motor that elementary and middle school student can build with little or no guidance. Current flows through the wire coil and creates an electromagnet. One face of the coil becomes a north pole, the other a south pole. The permanent magnet attracts its opposite pole on the coil and repels its like pole, causing the coil to spin.
- 04/03 - Making Your Own Salt Piece: This activity provides instructions for making a salt structure that grows spontaneously from a salt solution.Salt crystals form as solutions evaporate and become more concentrated.
- 03/27 - Knowing North: Understanding the Relationship Between Time and the Sun Activity: This activity provides instructions for telling which way is North on a sunny day using only a watch. If we can use our location and the sun to tell us about time, can we use time and the sun to tell us about our location? In this easy experiment, you'll see how the place of the sun in the sky is related to where we are on the earth.
- 03/20 - Black Magic Activity: This activity provides instructions for discovering the secret colors hidden in a black marker.Most nonpermanent markers use inks that are made of colored pigments and water. How does Black Magic work? Why do some black inks separate into many colors on a wet coffee filter? Why does mixing many colors of ink make black?
- 03/13 - Make Your Own Rain Stick Activity: This activity provides instructions for making a rain stick from a cardboard tube, rice or uncooked beans, and nails. Turning over a closed cylinder containing uncooked rice or beans produces the sound of falling rain.
- 03/06 - Outrageous Ooze Activity: This activity provides instructions for using cornstarch and water to make an ooze which has the properties of both a solid and liquid.The behavior of this ooze relates to its viscosity, or resistance to flow. It gets more viscous when you apply a shearing force, such as stirring quickly with your finger or a spoon. Stir it slowly and it will flow more easily. Water's viscosity doesn't change when you apply a shearing force.
- 02/27 - Balloon Blow-up Activity: This activity provides instructions for generating and using bubbles from soda or vinegar and baking soda.Not all bubbles are made with soap. Blow up a balloon and see raisins dance using common kitchen supplies.
- 02/20 - Sliding Gray Step Online Exhibit: This online exhibit allows you to move two blocks of gray stripes into areas of white and black stripes. The gray stripes, which are all exactly the same shade of gray, can be made to appear lighter or darker by changing their position relative to the white and black stripes. This illusion is not fully understood, but it seems to be related to the way the eye determines relative shading. This exhibit offers a possible explanation for the optical illusion, explaining how light-sensitive nerves in the retina process information that the brain interprets as areas of light and dark.
- 02/13 - Find the Highest Note Online Exhibit: This online exhibit shows three aural illusions—the Shepard Scale, the Tritone Paradox, and the Risset Scale. The three illusions, by showing how hard it is to figure out which tone is higher, demonstrate limitations in our ability to decipher auditory information. These illusions challenge students to analyze what they are hearing. The aural paradoxes they find are used to study human perception, emotions, and the workings of the brain.
- 02/06 - Droodles Online Exhibit: Droodles is a name that combines doodles and riddles. At this exhibit, you are briefly shown sets of images and asked to draw them from memory. In one set of drawings, the names of the images are nonsense words, while in the other set the names are helpful in describing the images. This exhibit shows that if random information can be arranged in a way that makes some sense, it will be easier to remember.
- 01/30 - Continental Drift Animation: The animation (in Flash and non-Flash versions) shows the supercontinent Pangaea ("all lands") fragmenting into the continents that exist today. Short text passages present some of the evidence that supports the theory of continental drift.
- 01/23 - Cell Explorer Online Exhibit: This online exhibit looks at the structure and function of living cells, including where people get the energy their bodies need to move around, how one cell divides into two, and how cells build the proteins they use to function.
- 01/16 - Build a Solar System Activity: This activity provides instructions for making a scale model of the Solar System and learning the REAL definition of "space." Using an interactive form to calculate the distances between the planets based on the diameter of the Sun you want your model to be scaled by, you can create a scale model of the solar system that accurately reflects the distances between the planets.
- 01/09 - Balancing Ball "Snack": This activity (aka "snack") provides instructions for suspending a ball in mid air using a hair dryer. This snack illustrates the following ideas/principles: Bernoulli's Principle, fluid flow, airstream, air pressue, curved surface, air shadow.
- 01/02 - Cow's Eye Disssection: This Web site provides a close-up video of the dissection of a cow's eyeball, and step-by-step directions for doing a dissection. The site also includes background information on vision, and an interactive diagram of the eye.