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Learners make a refrigerator that works without electricity. The pot-in-pot refrigerator works by evaporation: a layer of sand is placed between two terra cotta pots and thoroughly soaked with water.

Learners analyze mixtures of dyes using filter paper chromatography. They place spots of the different dyes at the bottom of a piece of filter paper, and hang the paper to touch the surface of water.

Visitors mix water and sodium bicarbonate (baking soda) in a large flask. They then add citric acid to the mixture and stopper the flask. The resulting reaction creates carbon dioxide gas.

Visitors separate a mixture of pebbles, salt crystals, and wood shavings by adding water and pouring the mixture through a strainer.

Visitors mix urea with water in one flask and mix calcium chloride with water in another flask. They observe that the urea flask gets cold and the calcium chloride flask gets hot.

Visitors prepare six solutions combining vinegar and ammonia that range incrementally from acid (all vinegar) to base (all ammonia).

Visitors observe a bottle with a balloon attached around the mouth. The bottle contains a solution of yeast, sugar, and water.

Learners use a universal indicator to test the amount of sodium hydroxide needed to change the pH of plain water compared with the amount needed to change the pH of gelatin.

Learners build models of sinkholes to gain an intuitive knowledge of their physical aspects.

This lesson (on pages 15-24 of PDF) explores how sound is caused by vibrating objects. It explains that we hear by feeling vibrations passing through the air.

Learners test solutions of water, sugar, salt, and hydrochloric acid for electrical conductivity. They immerse leads from a lighting device (a battery pack connected to an LED) into each solution.

Learners build a filter from old soda bottles and dirt. They create polluted water, and pour it through their filter to clean it.