How to Make a Cloud in Your Mouth

Description:  This phenomenon can be used to show how water moves from the atmosphere to the hydrosphere. The humidity of the air in the mouth is increased by moving the tongue, releasing water from the salivary gland. The pressure in the mouth is increased and then rapidly decreased causing small droplets of water to form. The same phenomenon occurs as moist air moves up in the atmosphere eventually forming clouds. A light can be used to make the cloud more visible.

Web Resource:  The Kids Should See This

Learn how to make a wispy cloud come out of your mouth, even when it's not cold out. Like any awesome trick, physics is to thank for the mouth cloud. This simple and fun demonstration can be used to explain the cloud in a bottle experiment, and real clouds in the sky.

Why Does Cutting an Onion Make You Cry?

Description:  This phenomenon can be used to illustrate both chemical reactions and the particle nature of matter. Onions gather sulfur from the ground to form large organic compounds. When the cells in an onion are breached (during cutting or eating) they release sulfenic acid which becomes a sulfur containing gas that eventually reaches your eye. Your eyes produce tears to remove the irritant. Students could speculate on how the irritant reaches your eyes and even investigate possible solutions to this problem. This phenomenon was submitted by Brian Babulic.

Web Resource:  Science News for Kids - Informational Text Article

This week Reactions takes science into the kitchen. We're looking at the chemistry behind why onion chopping makes you cry. We get to the bottom of this teary phenomenon and reveal exactly what chemical mechanisms trigger it. The video also features a few chemistry-backed tips you can try at home to stop the tears before they start.

Fire Piston

Description:  Fire pistons have been used for hundreds of years as a fire starter. Tinder is place in a seal tube and a piston is rapidly pushed into the tube. The air is compressed increasing the pressure and temperature until the ignition point of the tinder is reached. A diesel engine works in a similar fashion. This phenomenon can be used to introduce the particle model of air and temperature as a measure of the kinetic energy of particles.

Web Resource:  Fire piston - Wikipedia

Fire piston filmed in slow motion with the Phantom Flex at 2500fps and 5000fps.

Milk and Soap Experiment

Description:  Milk is made up of water, fat, and proteins. Each of these molecules have charges and are held together by intramolecular forces. When the dish soap is added to the plate it quickly disperses across the surface as it is attracted to the water molecules and the food coloring is pulled along. This could be used as an anchoring phenomenon on matter, materials, or intramolecular forces.

Web Resource:  Colors on the Mooooove - ACS

Watch what happens when you put a drop of dish detergent into a plate layered with milk and food coloring! James Kessler explains the chemistry that causes this tie-dye-like reaction and gives a demonstration for kids to follow along with at home. Try the experiment at home! http://www.acs.org/content/acs/en/education/whatischemistry/adventures-in-chemistry/experiments/colors-move.html Subscribe! http://bit.ly/AmerChemSOc Facebook!

Desert Beetle Harvests Water

Description:  Certain species of darkling beetles that live in the Namib Desert are able to harvest water vapor using an ingenious series of tips and bumps on their wing scales. The water droplets start to form on the tips and then flow off the waxy bumps to be collected by the beetle. This structure allows the beetle to survive in an incredibly arid environment. It could also be used by engineers to develop a similar system for collecting water for humans. Students should use this and other plants and animal phenomenon to start designing their own solutions to human problems.

Web Resource: Water Vapor Harvesting - Ask Nature, Darkling Beetles  

Namib desert beetles live in an area with little ground water, so how is it that they have no trouble finding H2O? Find out how the resourceful insects use their wing scales to absorb water droplets from fog, and how we can use them as a model for combating water shortages.

Supercooled Water

Description:  Supercooling occurs when the temperature of a liquid is lowered below the freezing point without forming a solid. In the case of water it needs a seed crystal or a nucleation site to start forming ice. If the water has been filtered through reverse osmosis or chemical demineralization it can be safely cooled below the freezing point. Simply shaking the bottle forms solid ice.

Web Resource:  Supercooling - Wikpedia

simple demonstration of supercooled water and rapid nucleation.

Indestructible Coating - Polyurea

Description:  In this video a watermelon is covered with a polymer and survives a drop from a large tower. The polymer is formed when two reactants join to make a flexible and durable polymer known as a polyurea. The chemical reaction is exothermic, releasing heat as the reactants combine. This phenomenon could be used in a unit on chemical reactions, extended structures or chemical engineering. The company Line-X uses this polymer to make bed liners for pickup trucks.

Web Resources:  Polyurea - Wikipedia, Line-X

Used in everything from bullet-proof vests to the walls of the Pentagon, polyurea's strength comes from its long-chain molecules.

Burning Steel Wool

Description:  This is an excellent phenomenon to discuss chemical reactions and the conservation of mass. Steel wool is burned leading to an increase in mass. When doing this in class show the students the burning steel wool to begin with and have them predict the change in mass. Most students believe the mass will either increase or decrease. This phenomenon can be used at the beginning of a unit on chemical reactions and students can investigate their individual models. (e.g. mass comes from fire, oxygen, carbon, etc.)

Web Resources:  Combustion of Iron Wool - CFNS Experiment 36

High School Chemistry Mass change during a chemical reaction Iron wool/steel wool is placed on an electric balance and ignited using a burning splint. The change in mass can be observed as the iron wool burns. Students should be able to explain why the mass reading on the balance increases at the end of the experiment.

A good experiment for youngsters.Ask first: Does iron burn? 'No' they say. Ask: When things burn do they get heavier or lighter? 'Lighter' they say. Use iron wool, not steel wool and get the finest grade you can get from the ironmongers.

Reusable Heat Packs

Description:  This phenomenon uses a supersaturated solution of sodium acetate. Clicking the metal disc releases a small number of crystals of sodium acetate which act as nucleation sites for the crystallization of the sodium acetate into a hydrated salt. Energy is released from the crystal lattice. The heating pack can be placed in boiling water and the sodium acetate can be dissolved again. This phenomenon shows how bond energy can be released.  It also shows the importance of chemical engineering and could lead to a section where students design a device (or application) of their own.

Web Resource:  Chemical Heat Pack - Wikipedia, Snappy Heat - Amazon

Clicking the metal disk inside causes a few of liquid sodium acetate molecules to flip to a crystallized state causing a chain reaction. The solidifying liquid creates 130°F of exothermic heat in the process. You can boil the package to return the crystallized sodium acetate back to a liquid form for reuse.

The Collapsing Train Car

Description:  The collapsing train car can be used as an anchoring phenomenon on a unit related to the structure and properties of matter. The macroscopic implosion is caused by a decrease in pressure within the train car and air pressure crushing the car. To fully understand this phenomenon students must understand what is going on at the microscopic level. This phenomenon can be demonstrated at a smaller scale in the lab using an empty soda pop can (containing a small amount of water) that is heated and then inverted in water.

A railroad tank car demonstration imploding after placing a vacuum on the tank with the vacuum safety valves disabled or removed. If anyone has more of this video or similar videos let me know.

Ice Cube Spikes

Description:  Ice cube spikes form when the exterior of the ice cube freezes first and the expanding water from the inside is forced out through a small hole or weak spot in the exterior. The phenomenon can be used to show the reversible change of freezing in elementary or the intermolecular forces between molecules in high school chemistry.

Web Resource: Spikes on Ice Cubes

Uploaded by bloo777 on 2016-01-03.

Why do spikes form on ice cubes? Without them the world would be vastly different. Awesome Jingle by Accent: http://bit.ly/AccentVe Thanks to Prof. Stephen Morris from UofT: http://bit.ly/1GFANBE Filmed in part by Martin Marek in Olomouc, Czech Republic Time lapse of a growing ice spike by Lesley Hill, Russ Sampson and Edward Lozowski, with technical help by Kenny Lozowski.

Brinicles

Description:  As ocean water freezes into solid ice the remaining saltwater forms into icy "stalactites" that descend into the ocean. This can be used as a phenomenon in an elementary class to show changes in state. In middle and high school the chemistry can be explored more deeply.

Web Resource:  Brinicle - Wikipedia

Brine icicles form with sinking supercooled water. Video by Umi, diver in the video is Steve Rupp.

Floating Whiteboard Ink

Description:
I learned about this phenomenon when a teacher spilled their water on my whiteboard.  Make sure to use a plate with an impermeable surface.  It's a great phenomenon for intermolecular forces.  Surface chemistry, temperature, color, ink type, polarity, salinity, and many more factors affect this phenomenon.  

Web Resources:  Drawing on Water - It is so surreal  - YouTube

Discovered this when a teacher spilled his water on my whiteboard.