Martin Gardner
1) pg 12 Float a small glass in a beaker filled with water, then add to the glass marbles, pebbles, or other small heavy objects, until the glass is close to sinking. Mark the water level of the beaker. Remove the glass, dump the marbles, and refloat the empty glass. Will the water level rise or fall?

2) pg 17 Poke three holes in a carton and apply pressure on them. Fill the carton with water and then release pressure. Which hole will allow the water to travel the greatest distance?

3) pg 21 Put a few inches of water in a large glass bottle that has a small opening. Set the bottle on a low stove light. When the water boils, remove the bottle and very quickly attach the uninflated balloon's mouth to the bottles neck. The air inside the bottle contracts while it cools, drawing the balloon inside, turning it inside out, and inflating it.

333 Tricks
1) Pg 111: Cut a straw almost in half. Place one end in a cup of water and the other end in your mouth. Begin to blow and the water will rise in the straw. If blown hard enough, the water will rise to the top of the straw and will be sent in fine droplets across the table.

2) pg 113: Cool a jug in the refrigerator for an hour. Remove, and place a balloon over the mouth of the jug and let it stand. As it warms, the balloon will be blown up.

Turning World Inside Out
H7: Fill a glass to the top with water. Place a card over the top of the glass, and while holding your palm on the card, turn upside down. Release, and observe the card hold the water in the glass.

H16: Fill a glass with water. Have someone estimate the number of pennies you can put into the glass before it overflows. This is a good demonstration of surface tension.

Physics For Every Kid.
pg 58: Fill a large jar three-quarters full of water and place a small closed bottle in the water. If it does not float on the surface, get a smaller bottle. Remove the small bottle and add a small amount of water. Close the lid and replace the bottle in the big jar of water. The bottle should slowly sink to the bottom. Remove or add water to the small bottle until it sinks at a slow rate when placed in the water. Remove the bottle and add 1/2 cup of salt to the large jar of water and stir. Replace the small bottle in the jar and observe its position in the water. Continue to add 1/2 cup of salt at a time until 2 cups have been added. Observe the position of the small bottle in the salty water after each measure of salt has been added. The bottle will rise as more salt is added.

pg 62: What happens to water level when you throw cargo over board? The water level drops.