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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

 

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

 

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

 

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

 
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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  

 

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

 
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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

 

Sugar and Sulfuric Acid

Description:  When sulfuric acid is added to sugar it removes the water leaving elemental carbon. The water quickly turns to water vapor creating the pores in the black snake-like column. This dramatic phenomenon can be used to illustrate chemical reactions, thermal energy released during a reaction, and conservation of mass. Safety precautions should be taken whenever dealing with acids.

Web Resource:  Sulfuric Acid and Sugar Demonstration - Thought Co.

 

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

 
 

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

 

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.

 

 

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