Free Everything Kids' Magical Science Experiments Book by Tim Robinson Page A

caused the effect you observe.
    Did You Know?

    The pressure of the outside air, called atmospheric pressure, is 14.7 pounds per square inch. That means that for every square inch of flat surface, the weight of all the air above it is 14.7pounds.
Science Concept
    We know that gravity makes objects fall to the ground. In general, water obeys this law. However, when the pressure is strong enough, water can actually overcome the effects of gravity and move upward into the jar. This only happens when the air inside the jar is removed or reduced to the point that outside air pressure can push the water up into the jar. Atmospheric pressure is constantly pushing down on the water in the pan. If you were to place the jar over an unlit candle, the pressure on the water inside the jar would be the same as the pressure on the water outside the jar. Only when the candle burns up and consumes some of the oxygen inside the jar does the air pressure inside drop. This lower air pressure cannot overcome the outside air pressure and the water is forced up into the jar.
Materials
Glass or metal pie plate
Several glass bottles of different heights and diameters
Several candles of various sizes, shapes, and heights
Water
Marking pen
Procedure
Fill the pie plate with water.
Place the candle in the middle of the plate, taking care that the top of the candle sits above the surface of the water.
Place the jar, mouth down, over the candle to verify that the water level inside the jar is the same as the water level outside the jar.
Remove the jar and light the candle.
Replace the jar over the candle. Watch as the candle goes out and the water is sucked up into the jar.
When the water level inside the jar stops rising, use your pen to mark the water height.
Carefully remove the jar from the water. The extra water in the jar will pour back into the pie plate.
Repeat steps 2–6, either with a different candle or a different jar. Each time you produce a new mark on the jar, record the diameter and height of the jar and candle.
When you have completed all your tests, analyze your data to determine which combination of jar and candle produced the greatest effect on the water.
Questions for the Scientist
What type of jar was the most effective for drawing water up in this experiment?
How might the jar diameter mislead you to think that one jar pulled up less water than another, when in fact it may have pulled more?
What type of candle was most effective for drawing water up in this experiment?
What effect might the water temperature have on your results in this experiment? Would warm water react differently than cold water?
Conclusion
    You can build a home version of a barometer using a setup similar to this one. By placing a bottle inside a container of water, you can measure the changes in the water height each day as the atmospheric pressure changes. The higher the atmospheric pressure, the higher the water will rise inside the bottle. This concept is similar to the way atmospheric pressure is reported by television news. You may hear something like this: the pressure is 29.9inches and rising. This is actually a measure of how high mercury would rise in a formal barometer. Good weather is typically associated with high pressure, while lower pressure often brings bad weather. In your experiment, the lower pressure inside the jar made the outside air pressure seem “high,” which caused the water to rise into the jar.
Funny Forecast
    Meteorologists use a lot of high-tech scientific equipment to predict the weather. But you can use something much more simple — a piece of rope! To find out how this “magic” weather predictor works, figure out where the puzzle pieces go, and write the letters into the empty grid.

Demo version limitation

Appendix B Puzzle Answers
    ALMOST IMPOSSIBLE • page 5

    NO ONE CAN SEE 1 • Page 7

    NO ONE CAN SEE 2 • page 7

    DOWN AND UP • Page 8

    COLD TO HOT??? • Page 17

    GOING UP