Hobbies And Interests
Making Rain
You can see part of the water cycle in action with a teakettle, ice and an aluminum pie tin. Boil water in the kettle until steam comes out the neck, and disappears into the air. This is evaporation. Place the ice cubes in the pie tin, and hold it over the steam. Be careful to keep your hands and face away from the steam to avoid burns. Water droplets will appear on the bottom of the pie tin, forming condensation. As the water droplets increase in number and size, they will begin to drip off the bottom of the pie tin as precipitation. You have just seen the three major steps of the water cycle; water turns into water vapor and rises, condensation occurs as the cooler temperatures of the upper atmosphere turn the water vapor into droplets, and precipitation as the condensed water droplets join and fall to Earth as rain, snow, sleet or hail.
Humidity
Humidity is a measurement of the amount of water vapor in the air. It affects the natural world, and you experience some of its effects on a hot, humid day when you perspire and cannot seem to cool down. In high humidity, pinecones protect their seeds by closing. In low humidity, pinecones open to disperse their seeds. Observe the effects of humidity by making a hygrometer with four long, lightweight pinecones with scales that are open, four wide-mouth glass jars that are taller than the pinecones and have screw-on lids, a spray bottle of water, masking tape and four small pieces of plasticine.
Put a piece of plasticine in the bottom of each jar, and attach the base of the pinecone to it. Mist the pinecone, screw on the lid and turn the jar upside down. Observe the jars periodically for three or four hours, recording your results. After the pinecones are closed, leave the jars open overnight. Record your observations. Fill the lids of two jars with water, and screw the jars upside down onto the lids. Screw the lids onto the remaining jars. Tape down all the lids. Put one wet jar and one dry jar in a dark place, and the remaining two jars in a sunny place. Observe and record your results periodically throughout the next two days.
Wind and Air Pressure
Air tries to equalize differences in pressure, creating wind. Observe this process by blowing up a balloon; twisting the opening and holding it closed. You have forced a lot of air into it, compressing the air molecules to create high air pressure inside the balloon. Let go of the end of the balloon, and allow the air to whoosh out like the wind. The air comes out quickly because the high air pressure inside the balloon forces the air into the lower air pressure outside the balloon.
The Heating Power of the Sun
You can learn about the power of the sun with a 2-by-3-foot blackboard, a wet cloth, two thermometers, colored pencils and two plastic bowls of ice cubes. This experiment works best on a sunny day.
Place the blackboard on the ground where half is in sunlight, and the other half is in the shade. Place one bowl of ice cubes and a thermometer near the black board in the sunlight. Place the other bowl and thermometer near the blackboard in the shade. Check on the experiment in 20 minutes. Wipe the wet cloth across both the sunny and shaded portions of the blackboard and observe the results. Feel the temperature on both parts of the blackboard, check the bowls of ice cubes and record the temperature. Continue to check every 20 minutes. Graph the results using different colors for the sunny blackboard, the shaded blackboard, the temperature on each thermometer and an estimate of the percentage of ice that melted in each blow. Plot these items on the x-axis, and plot the time on the y-axis.