Greenhouse Effect

Greenhouse Effect

Recreating the Greenhouse Effect

The Earth's climate has changed many times in the past. Subtropical forests have spread from the south into more temperate (or milder, cooler climates) areas. Millions of years later, ice sheets spread from the north covering much of the northern United States, Europe and Asia with great glaciers. Today, nearly all scientists believe human beings are changing the climate. How can that be? Over the past few centuries, people have been burning more amounts of fuels such as wood, coal, oil, natural gas and gasoline. The gases formed by the burning, such as carbon dioxide, are building up in the atmosphere. They act like greenhouse glass. The result, experts believe, is that the Earth heating up and undergoing global warming. How can you show the greenhouse effect? Two identical glass jars 4 cups cold water 10 ice cubes One clear plastic bag Thermometer

Take two identical glass jars each containing 2 cups of cold water. Add 5 ice cubes to each jar. Wrap one in a plastic bag (this is the greenhouse glass). Leave both jars in the sun for one hour. Measure the temperature of the water in each jar.

Make a Thermometar

Make a Thermometar

A thermometer is an instrument that measures the temperature. Temperature is measured in a scale called Fahrenheit (by most people in the United States) and in Celsius or Centigrade (used by scientists and by people in many other countries). The point where water freezes is 32 degrees Fahrenheit (F for short) and 0 degrees Celsius (C). The point where water boils is 212 degrees F and 100 degrees C. If you want to know how to convert from F to C or from C to F.

Some scientific thermometers use the Kelvin scale, where 0 Kelvin is called absolute zero - a place where there is no movement of any parts of matter, where substances have no thermal energy. It's about minus 273.15 degrees C (below 0° C) or 459.67 degrees below 0° F. Scientists have never been able to measure anything at absolute zero, though they have gotten very close.

Thermometers help us know what the weather will be like. If it will be 90°F outside, we're not going to put on a winter coat. Or if it's below zero, we won't be wearing shorts. Here's a way to show how a simple thermometer works.

Tap water Rubbing alcohol (do not drink this) Clear, narrow-necked plastic bottle (11-ounce water bottles work well) Food coloring Clear plastic drinking straw Modeling clay

Pour equal parts of tap water and rubbing alcohol into the bottle, filling about 1/8 to a 1/4 of the bottle. Add a couple of drops of food coloring and mix. Put the straw in the bottle, but don't let the straw touch the bottom (DO NOT DRINK THE MIXTURE). Use the modeling clay to seal the neck of the bottle, so the straw stays in place. Now hold your hands on the bottle and watch what happens to the mixture in the bottle.

Steamboat Power

Steamboat Power
A steamboat or steamship, sometimes called a steamer, is a ship in which the primary method of propulsion is steam power, typically driving propellers or paddlewheels.

Make a Steam-Powered "Rocket Boat"

What do you need?

1. Metal tube (a cigar tube works great -- ask an adult to get you one)
2. Two pieces of strong, stiff wire (like clothes hanger wire) about 18-inches long
3. Cork that fits snuggly into the end of the tube
4. Two food warmer candles (in metal cups)
5. Balsa wood (4 inch by 8 inch, 1/2-inch thick)
6. Masking tape
7. Hammer and three nails
8. Matches

What to do?

Put the cork into the end of the metal tube making sure its very tight. Carefully poke a hole through the cork with a nail.
Take the two 18-inch lengths of wire. Wrap the wire around metal tube about one-inch from each end of the tube, and twist the wire tightly with the pliers so the tube is firmly held by the wire and won't slide.
Cut a boat shape out of the balsa wood, making a triangle bow at one end. Hammer two large nails in each end about one inch in from each end. The nails will help to stabilize.

Mount the two candles about 1-1/2 inches from each end of the wood. Use loops of masking tape to stick the metal cups to the wood. Take the tube with the wire and mount the tube so the wire will hold the tube just above the candles. Wrap the ends of the wire around and under the board and twist the ends neatly on the underside. (See picture.)
Carefully remove the cork from the tube and fill the tube about three-quarters full with very hot water. Tightly replace the cork. Make sure water will drip out the hole in the tube. Fill up a bath tub or a large sink with water. Put your boat in the water and ask an adult to carefully light the candles.