Sci-ber Text - 4th Grade

Weather Observations - Weather Prediction

SUMMER SIZZLES!
It is another one of those hot sweltering days. As the temperature soars towards 100°Fahrenheigt, you and your brother decide it's time to go to the swimming pool. Before you go to the pool, you quickly gobble down a grilled cheese sandwich and some chicken noodle soup for lunch. You finish lunch with a popsicle then quickly run to your room to grab your towel. As you head out the door, you suddenly realize that the weather has changed dramatically. The blistering heat has been replaced by a cool breeze from the north. Your plans have suddenly changed. You no longer need the pool to cool you off, it seems that Mother Nature has already taking care of that.

A CHANGE IS IN THE AIR!
What happened in the above story that caused such a sudden change in the weather? Why was it blistering hot before lunch, and a bit nippy after your grilled cheese sandwich?

There are giant masses of air that move in the atmosphere over Earth. These air masses form over different parts of Earth and can be warm or cold, dry or moist. When two different types of air masses meet, a front forms. When a front moves over an area, the weather changes.

Let's Map it Out!
Using a newspaper weather map, do the following activities.

Locate a warm front on the map. Circle it in red.
Locate a cold front on the map. Circle it in blue.
Locate a stationary front (this is a mix of a warm and a cold front) on the map. Circle it in another color.
Use the map to find out if there are any changes coming to the area where you live.

You're the scientist!
Cold and warm air acts differently. It is difficult to see how they act because air is invisible to us. You will use water to demonstrate what happens when cold and warm air meet. Cold and warm water act a lot like cold and warm air.

Materials:

Glass 9x13 inch baking dish
Overhead projector
Room temperature water
Very cold ice water
Very hot tap water
Blue food coloring
Red food coloring

Procedure:

Fill the baking dish with room temperature water.
Add a few drops of blue food coloring to the very cold ice water.
Slowly pour the cold blue water into the tub of clear water. Pour the water very slowly so that it doesn't stir.
Explain what happened. Draw a picture of what you observed.
Add a few drops of food coloring to the very hot tap water.
Very slowly pour the hot water into the tub of water.
Observe what happens and draw a picture to represent your results.

In the activity you probably noticed that the cold water sank to the bottom. Cold water is heavier, or denser, than room temperature water. The hot water probably stayed at the top. Hot water is lighter, or less dense, than room temperature water. This is also true of air. Warm air rises. That is why hot air balloons rise into the air, and cold air sinks. When masses of cold and warm air meet, it causes changes in the weather. Cold fronts produce violent weather such as blizzards and thunderstorms. The weather caused when a cold front moves over an area usually does not last too long. Warm fronts also produce stormy weather. The weather associated with warm fronts however, is not as severe as cold front weather. Storms associated with warm fronts may last for several days.