Description: An endothermic reaction lowers temperature in flask so that the flask will freeze and stick to a wet piece of wood. An endothermic reaction is used in drug store instant cold pack. An exothermic reaction in a Styrofoam cup will significantly raise the temperature in the cup.

Concept: Some chemical reactions absorb heat from the surroundings, resulting in a cooling of the surroundings (Endothermic Reactions). Some chemical reactions evolve heat, resulting in a warming of the surroundings (Exothermic Reactions).

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Description: When two clear solutions (one blue and one colorless) are mixed together they generate light. The resulting solution has a bluish glow. It is nicely displayed by running it through a spiraling tube.

Concept: Chemical energy can be converted in to other forms of energy - sometimes it is converted to heat (exothermic reactions), electricity (batteries), and sometimes into light.

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Description: Four different metal rods (lead, iron, copper, and aluminum) are heated and then placed on a block of paraffin wax.

Concept: Depending on the specific heat of the metal, the different metals will be able to melt more or less paraffin wax.

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Description: A small chunk of phosphorus is ignited by flame and quickly plunged into a flask containing oxygen gas. The resulting reaction produces heat, smoke and a spectacular bright light that last for 5-10 seconds.

Concept: Finely dispersed phosphorus will readily ignite in the presence of oxygen at room temperature and must be stored under water or in a solvent such as carbon disulfide.

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Description: Water is added to NaCl and the temperature decreases by about 3°C; water is added to KNO3 and the temperature decreases by about 12°C; water is added to LiCl and the temperature increases by about 70°C.

Concept: Heats of solution can be exothermic and endothermic.

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Description: About 30 seconds after the acid is added to the sugar, a column of black carbon grows up from the beaker. There are vapors and the smell of burned sugar.

Concept: Sulfuric acid is a strong acid and has a strong affinity for water.

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Description: Two white powders are mixed. The two will react when initiated by a drop of acid on the end of a long glass rod (the magic wand). The reaction is violent a results in a "poof" of heat, flames, and smoke.

Concept: Exothermic reactions produce a lot of heat. Potassium Chlorate is a strong oxidizing agent; a fire may start when it is mixed with combustible materials.

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Description: The blowers in the Collisions Cube are set at low power on each side. The side with the ping-pong balls is said to represent reactants, while the empty side is said to represent products. The power should be low enough so that no ping-pong balls change sides. The hole at the top is representative of the energy barrier that reactant molecules must overcome in order for the reaction to proceed. The students are asked to propose a change to the system that would allow for product creation.

Concept: Product creation is sometimes limited by the amount of activation energy provided.

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Description: Sulfuric acid is added to 0°C water in one beaker and 0°C ice in another. The temperature in the beaker of water increases and the temperature in the beaker of ice decreases.

Concept: Heat is released when acid reacts with water causing the temperature of the water to increase. However if the water is frozen initially the heat from this reaction is absorbed by the phase change of the ice molecules to liquid water. Additionally, the temperature of this water will decrease due to the freezing point depression effect of the solute (the acid).

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