Janice VanCleave’s Crazy, Kooky, and Quirky Chemistry Experiments

Janice VanCleave’s Crazy, Kooky, and Quirky Chemistry Experiments — page 5
expando Purpose To observe the effects of expanding gas Materials empty 2-liter plastic soda bottle timer ½ cup 125 ml tap water 1 tablespoon 15 ml dishwashing liquid saucer NOTE This experiment requires a freezer Procedure 1 Place the empty soda bottle in a freezer for two minutes or more 2 While you are waiting mix the water and dishwashing liquid together in the saucer 3 Remove the soda bottle from the freezer and dip its open end in the soapy water 4 Stand the bottle on a table and observe what happens NOTE If a soap bubble does not form over the mouth dip the bottle in the soapy water again Results A soap bubble forms over the mouth of the bottle Why As the temperature of molecules decreases molecular motion decreases and the cohesive force increases pulling the molecules closer together Cooling caused the air molecules inside the bottle to move closer together removed from the freezer the cold air inside it heated up 8 Janice VanCleave’s Crazy Kooky and Quirky Chemistry Experiments