Purpose:

Glass tube filled with distilled water and mounted above the words "CHOICE URANIUM OXIDE."

Demonstrate that when the words are read directly, they appear normal but, when viewed through the tube filled with liquid, some letters are inverted. Pass (with care) the apparatus around the classroom or otherwise make it available for viewing. Ask the students to formulate an explanation. The demonstration can also be placed on the Cannon Document Camera for class viewing.

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