001, Under-Water Fireworks
Chlorine gas is bubbled up along with acetylene gas through a large graduated cylinder filled with water. Where the bubbles of the two collide, an instantaneous, bright flash of light occurs.
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002, An Egg-splosive Demonstration
A wide variety of containers has been used for illustrating the explosive power of a combustible gaseous mixture. These explosions are especially impressive when set up as time-delayed reactions -- with a flame burning over an upper orifice, then backfiring into the container. The following demonstration is the latest addition to this bevy of booms, but it utilizes one of nature's oldest containers--an egg shell.
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003, Limiting Reagent - Explosions
An inexpensive calibrated plastic sparking apparatus (known as a eudiometer) is assembled. Combining volumes can be determined for the ratio of H2 to O2 and the ratio of H2 to air. This experiment duplicates one of the landmark experiments in chemistry with an explosive demonstration of limiting reagents and mole ratios.
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004, Kaleidoscoptical Sugar Rotation
A radially polarized filter is placed on an overhead projector stage and a regular (parallel) polarized filter is positioned above it. As expected, the image produced shows four quadrants, alternating light-dark-light-dark. As an optically active solution (corn-syrup) is poured between them, the image rotates and separates into a beautiful spectrum of colors.
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005, Paramagnetic Oxygen Bubbles
Oxygen is a paramagnetic gas. This property is illustrated by pulling bubbles of oxygen about on the surface of water with a strong magnet.
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006, Cereal Flake Races
Many breakfast cereals contain trace amounts of iron in its elemental form. Flakes of these cereals can be floated on water in a petri dish on the overhead projector and moved about by a strong magnet.
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007, Iron in Cereal--Separation
Many breakfast cereals boast that they contain iron, an essential part of our daily diet. A slurry of cereal is stirred with a strong magnet held to the outside of a transparent container. A spot of iron particles appears and is moved with the magnet.
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008, One Dollar's Worth of Iron
Paper dollar bills are printed with magnetic inks. This can be shown by dangling a dollar bill in one hand, and showing how the bottom end can be moved when a strong magnet is brought near. This can be followed by the extracting the magnetic ink from the bill using a blender and a magnet. Students are surprised when you destroy money--the sample for analysis. This destruction is the dilemma encountered with most analyses--for example, authenticating art masterpieces or an artifact such as the Shroud of Turin. Students are also amazed at how much iron is in a single dollar bill.
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009, Flame Tornado
A paper towel is soaked in lighter fluid, placed on an evaporating dish and ignited, producing a 15-20 cm high flame. When this is placed on a screened-in lazy susan, and spun slowly, the flame is spontaneously transformed into a roaring meter-high pillar of fire. Different ions make a remarkable flame test demonstration.
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010, Water Tornado
Students are invited to participate in a race to see who can empty their jug of water the fastest. They soon find out that gravity is not the only force that can help them! This activity is a problem solving exercise which works especially well when coupled with the Flame Tornado demonstration (009).
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011, Glowing Tubes
The gas in a Tygon tube glows from the electric energy of a Tesla Coil. A plastic syringe is used to pull the vacuum. Glowing effects are possible by changing the path of the tubing.
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012, Electrifying Patterns
The gas in a round flask glows from the electric energy of a Tesla coil. Glowing rays of light discharge across the flask. You can move the glowing rays by moving your hand around the flask.
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013, Hero's Fountain
With no electrical cord or batteries or obvious energy input of any kind, a fountain spouts and sprays gracefully for quite a while. At first, the fountain looks like a perpetual motion machine. With time, however, and careful observation, a transfer of water can be noticed from a higher reservoir to a lower one, revealing the fountain to be nothing more than an elaborate siphon.
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014, Hydraulic Elevator
In an age-old demonstration, a water-filled bottle with a card over its mouth is inverted, and atmospheric pressure is shown to be greater than the water pressure, for the card is held suspended in place. The following activity serves as a logical extension of that demonstration. The question is posed: if atmospheric pressure is greater than the water pressure, then the net force on the card should be upward; why, then, does the card not move upward?
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015, Methane Mamba -- Snake Charming
Methane gas is bubbled up through a funnel of soapy water and a buoyant column of suds grows gracefully upward like a large bubbly snake swaying elegantly to the air currents in the room. Igniting this methane mamba provides for a rather charming effect! See safety precautions.
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016, Shrinking Suds
Liquid detergent is added to a graduated cylinder containing some dry ice subliming under water, and the foggy carbon dioxide bubbles that form spill out over the top. Once in contact with the air, however, these bubbles begin to shrink quite noticeably.
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017, Shrinking Bubble
Dry ice is added to a flask half-filled with water, and a fog rises to the rim. A soap film is drawn across the top of the flask. This film gradually inflates, stops growing, and finally shrinks as the CO2 is depleted. CO2 is clearly diffusing through the soap film as the bubble stops increasing in size while CO2 is still bubbling out of the water. Rings may be visible on the bubble.
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018, COª Crystal Ball
Have you ever gazed into a cloudy crystal ball...made from a soap film? Dry ice is added to a bucket of water. A soapy cloth is drawn across the lip of the bucket to create a soap film sheet. This film gradually inflates into a misty, colorful crystal ball that undulates gracefully to the air currents in the room! Gentle puffs of air set up resonance patterns in the crystal ball. This dramatic demonstration is a must around Halloween time.
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019, COª Leaky Faucet
Although you have probably seen a leaky faucet, you have probably never seen one that drips carbon dioxide gas! Foggy CO2 gas -- from dry ice subliming under water -- is passed through a faucet-like series of pipes, the mouth of which has a soap film across it. The dense CO2 bubbles that form, pinch off and fall rapidly downward, resembling a huge leaky faucet!
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020, Misty Smoke Rings
You can blow some beautiful, mystical smoke rings with dry ice and two disposable plastic cups.
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021, Ghost Crystals
A vial appears to contain only water and a small string noose hanging down into it. When the string is lifted out, a large shiny "crystal" is found to be tied up in the noose. When the string is lowered back into the water, the "crystal" again becomes invisible! In a similar variation, a secret message is revealed by pouring water in a petri dish of "crystals".
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022, Goldenrod Messages
Spray a solution on a piece of yellow paper, and a secret message instantly appears.
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023, Ammonia Ghosts
Have you ever seen an ammonia ghost? You'll get a good look at one when you try this activity. They are pretty timid, though, for ghosts; in fact, a few drops of vinegar is all that it takes to scare them away! Ammonia diffuses through a paper towel into a large bottle of water containing phenolphthalein. Convection currents swirl the pink ghosts gently.
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024, pH Rainbow Tube
Start with a tube filled with green solution, add a few drops of acid to one end and a few drops of base to the other, and a whole spectrum of colors appears.
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025, Densi-Tee
A large cylinder contains water with a layer of coarse granular salt at the bottom and a golf ball resting on top of the salt layer. If left undisturbed, over the course of a few days (..weeks? ...months??) the top of the salt layer gradually descends as the salt dissolves, but the golf ball slowly levitates upward! Aside from the unique visual effect of seeing a golf ball hovering inside a solution, the overall slowness of the whole phenomenon is also quite remarkable.
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026, Sucrose Density
A cocktail called Pousse-Cafe is prepared by layering colored liqueurs one on top of the other. This demonstration uses colored sugar solution to achieve the same rainbow effect but with impressively sharp boundaries.
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027, Antibubbles--Solution Densities
A dilute detergent solution is squirted back into itself to form thin, spherical membranes of air known as anti-bubbles. A sucrose density gradient allows antibubbles to be suspended throughout the solution. These anti-bubbles display principles used to separate and purify very large biomolecules.
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028, Soap Films in Action
Several different frames are dipped in soapy water to illustrate the tension present in soap films. The films make a membrane like structure which tends to minimize its area.
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029, Structures with Bubbles
A variety of geometric frames both large and small can be constructed from relatively inexpensive materials. These may be used to illustrate the various molecular geometries, crystal lattice cell types, packing orientations, as well as cluster configurations -- as in the new and exciting field of fullerene carbon cages. These frames may also be dipped in soapy water to illustrate the tetrahedral configuration.
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030, Liquid COª
A small sample of dry ice is placed in the bulb of a plastic transfer pipet. The stem is clamped shut. In a matter of seconds, the subliming chunks of dry ice begin to melt and then boil at the same time. A Boyle's Law-type micro gauge can be incorporated, and experimental values for CO2's triple point pressure can be determined.
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031, Cartesian Diver-sions -- The Basics
A vast variety of squeezable-sinkable Cartesian divers can be made with the simplest of equipment, materials, and a little imagination. As the pressure changes, students can easily observe the effect on the volume of air within the divers.
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032, Cartesian Counters and Messages
Cartesian Counters and Messages. Place several numbered divers together in one bottle, but all with different densities, so they descend in order -- 1, 2, 3... (or with letters so that they spell out a secret message!)
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033, Diving Whirligigs and Open Retrievers
A whirligig may be added to a diver. The diver spins gracefully as it sinks, and reverse its spin on the way up. Attach arms and legs to make a diving ballerina! Or, place two divers in the same bottle -- one that barely floats and one that barely sinks, but with mechanisms or devices attached to them that enables the floating one to dive down and retrieve the sunken one off the bottom.
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034, Colored Closed-System Divers
Divers are sealed with hot glue to make closed system. Now, when the bottle is squeezed, instead of water being forced up into the diver's mouth, the sides of the diver are forced noticeably inward. The closed system is easier to transport, explain, and with added coloring observe.
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035, Cartesian Retrievers--Jaws in a Bottle
The shape distortion of closed-system Cartesian divers can be taken advantage of in many ways: for instance, wires may be attached to the sides of the diver and fashioned into "jaws" that hang downward. Then, when the middle gets pushed inward, the jaws spring open and a ferocious Cartesian shark dives downward, mouth open, to snatch an unsuspecting diver off the bottom!
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036, Ionic Crescendo
A piezo-electric buzzer and a battery are used to measure the conductivity of various solutions. This experiment is similar to ones using light to measure conductivity. The buzzer is sensitive enough to track the diffusion of a salt crystal as it dissolves to complete the circuit. By using a colored salt, the electrical conductivity, the buzzer intensity, is connected to the concentration of the salt, the color intensity.
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037, Radial Chromatography-Water
From just a few black dot "seeds" on a piece of filter paper bloom a variety of colorful flower patterns. A demonstration chromatogram on very large filter paper runs concurrently with smaller student chromatograms. Several student problem solving variations are suggested for students familiar with chromatography.
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038, Radial Chromatography T-Shirt Designs
Using radial chromatography, it is relatively easy to decorate T-shirts (or any other absorbent cloth material) with interesting radial patterns. This laboratory is similar to the water based experiment with filter paper.
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039, Teflon Tape
Plumbers Teflon tape (*PTFE = polytetrafluoroethylene) is a silky material with interesting properties. Use the tape as an open ended exploration of polymer properties. Messages written on the tape are easily distorted and reformed with the polymers.
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040, Cross-Linked Glue
A saturated borax solution is added to a glue/water mixture and the viscosity increases several orders of magnitude. The resulting "gluep" is either a bounce-able liquid or a slow-pouring solid -- or perhaps it's both -- and it has some intriguing properties.
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041, Solutions and Calibrations
A class set of volumetric flasks (each one with a slightly different volume) can be prepared from some Barnes dropper bottles. Students then use the flasks to prepare a solution with a specific molarity. (For example, everyone is required to make up a 1.35 M NaCl solution.) Since each flask is different, each student (or lab team) must do their own calculations, mass out their solute and follow the proper procedure to prepare the solution correctly. Since the molarities are all the same, they can be quickly tested for accuracy by measuring their density.
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042, Hydrometer
A plastic pipet is modified and calibrated to make a hydrometer. Densities of several solutions are measured. This experiment may be paired with BBExperiment 041 to test the solutions prepared by students.
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043, Mystery solutions -- 3
The students are paired off, and each group is given two identical sets of solutions, one labeled 1, 2, 3 and the other, A, B, C. The students try to identify the matching solutions. What makes the lab especially challenging and what prevents one student from doing all the work and what forces them each to write down their observations is that they must seat themselves across the room from their partners, keep back to back. Students communicate with messages "faxed" back and forth to their partners.
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044, Mystery Solutions -- 5
Solutions react with each other in many different ways. Some do not react at all. If you were handed one set of solutions labeled 1, 2, 3, 4, 5 and your lab partner were handed a matching set, labeled A, B, C, D, E could you work together to figure out which number matched up with which letter?
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045, Micro-Water Purification
This experiment is a micro-scale adaptation of the ChemCom Foul Water Lab I. Here modified pipets are used as separatory funnels, sand-filtration funnels, and charcoal absorption columns. 3-4 mL of foul water are converted into about 1-2 mL of clean water, and the students take care not to spill a single drop!
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046, Lite Margarine/Lite Salt Lab
Students investigate the meaning of the term "lite" as it applies to two food products. Equal amounts of Regular, Lite, and Extra-lite margarine are heated to separate into the oil and water layers. Then they compare regular salt with Salt Sense´ -- a lite salt claiming to be pure sodium chloride which somehow contains 33% less sodium per teaspoon than regular salt! By examining the crystals under the microscope and by comparing their relative volume changes before and after pulverizing, students can discover for themselves the secret to this claim!
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047, Vitamin C in Fruit Juices
How much do students really know about vitamin C and the relative Vitamin C contents of common beverages? Vitamin C (ascorbic acid) is titrated with iodine to the appearance of a starch endpoint color. Students plot results from five different concentration standards on a best-fit graph which is used as a calibration curve for the analyses of Vitamin C in a variety of common beverages. This quantitative experiment explores solution stoichiometry and analysis.
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048, Micro-Electrolysis of Copper Chloride
Using a 10-cm length of flexible aquarium tubing bent into a U-tube, a 9-V battery and some mechanical pencil "leads" as graphite electrodes, students can observe at their desks the reduction of copper ions at the cathode into beautiful branching crystals of copper metal, along with the oxidation at the anode of chloride ions into pungent-smelling bubbles of chlorine gas.
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049, Micro-Distillation Lab
A variety of plastic pipets can be cut up and joined together to make a very small and very quick distillation apparatus, complete with heating chamber, boiling chip, condensing tube with sleeve and collection bottle. A boiling hot water bath brings 2-3 mL of 30% ethanol solution to a boil in less than a minute. Successive distillate portions are collected and then tested for density and flammability.
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050, Micro Rockets
A small plastic rocket is constructed from the calibrated bulb of a graduated plastic transfer pipet. This bulb is filled with water, and then most of the water is displaced - first with hydrogen and then oxygen. Electrodes are inserted into the device. A spark causes the mixture to ignite and launch the rocket. Students are challenged to find the most "powerful" mixture and then use it to launch a rocket across the room!
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051, Iodine Clock Kinetics
Iodate and metabisulfite are dispensed at concentrations where the clock reaction requires about 10 seconds when the equal volumes of solutions are mixed. Students alter the conditions to make the color change in exactly 30 seconds. Students with minimal knowledge about kinetics usually succeed by applying scientific reasoning.
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052, Home Mixture Separation
This lab is intended as an open-ended, self-designed activity in which the students are presented only with the problem and a list of equipment available to them. They are required to develop and test out their own procedures. Handouts for HOME use are included but there are no movies because of the open ended nature of the activity.
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053, Hero's Engine
An easy steam engine (Hero's engine) is constructed from a soda can and a swivel. Burning fuel heats the engine to produce steam. The chemical energy in the fuel is converted to a frantic rotation of the can illustrating the conversion of chemical energy to thermal energy to mechanical energy.
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054, Captivating Activation
A potential energy barrier similar to an activation energy is modeled by a rubber device cut from half of a racquet ball. When the rubber device is turned inside out and dropped from a small distance onto a hard surface, the device snaps into its preferred shape and pops considerably higher than the point from where it was dropped. A Ping-Pong ball can be "launched" from the device with considerable velocity. This suggests an exergonic reaction in which some activation energy must be added before reaction can proceed.
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055, Closed Distillation Apparatus
An ethanol filled novelty device called a "hand boiler" consists of two blown glass bulbs connected by a glass tube with various loops. Several properties of vapor pressure are studied with this apparatus. Most remarkably, ethanol can be separated by distillation leaving a concentrated dye powder behind. This distillation is completely self-contained inside the apparatus, and driven by the heat of your hand! Students can feel, quite dramatically, the energy of evaporation by holding the bulb during the distillation.
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056, Iodine Clock Messages
Iodate and metabisulfite are mixed in a simple stop-flow apparatus with a flow path shaped into a message. The message appears from left to right as iodine forms in this classic clock reaction.
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057, Pouring Carbon Dioxide - Snuff a Candle
Carbon dioxide gas is generated and poured into a container. A burning candle lowered into the container goes out as the flame dips into the CO2 layer. The flame is readily supported by air in the same container.
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058, Hexane Fire Trail
Electric sparks and pilot lights, even at considerable distances, can light flammable vapor trails resulting in flash backs to the sources which are frequently flammable liquids. To illustrate this safety problem, hexane vapor is ignited in an angle iron to create a trail of fire.
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059, Instant Hot Air Balloon
Hot air balloons provide a wonderful example of applied science: the gas laws, in conjunction with the concepts of density and ArchimedesÕ Principle brought to bear on one of mankindÕs oldest preoccupations -- flight! Hot-air balloons have found their way into science museums and exhibit halls around the world, and many classroom activities have recently been developed for constructing workable, small-scale models, usually made out of tissue paper or light-weight plastic. The following describes the simplest imaginable hot-air balloon model, easy to build and quick to launch!
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060, Final Analysis -- A Group Exam
My final exam is an open-book, open-notes, group-work, lab-practical exam. Although none of these concepts is by itself new, I use some different twists and innovations that have made the activity especially effective and valuable -- so much so that I cannot see myself ever going back to the traditional exam system. Portions of one final exam are presented here as an example.
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