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In this lesson students will understand that there are reasons that summer and winter storms are different, and will discover the patterns for each.
Winter storms and summer storms in Utah come from two different sources. However, they both have a lot in common. Both storms tend to move from the west to the east. Both have moisture in them that comes from the Pacific Ocean. They have a low pressure for the moist, warm air to expand rapidly. Both have warm winds that feed into the low pressure as it is approaching. As the warm air expands rapidly it cools instantly to create cold air to make clouds and eventually could produce precipitation. Lastly, they both produce wind prior to the their storms. Usually the winds associated with the two storms are warm.
But there are some differences in the two storms. Winter storms are generally from October through April. Summer storms are generally from May through September. Winter storms have their beginnings from the north where the air is cold. Summer storms have their beginnings from the south where the air is warm. Winter storms bring in cold air from the north that can last for many days after the storm. After a summer storm the air may be cooler for a few hours but quite comfortable. Summer storms can produce violent, strong winds that can do a lot of damage. Winter storms will bring wind, but they won't do much damage. Summer storms can have thunder and lightning associated with them. Generally, winter storms don't have thunder and lightning. The whole process of a winter storm coming in can last up to a week from beginning to end. The whole process of a summer storm will only last a few hours. The barometer usually drops quite a bit before a winter storm, but the barometer doesn't drop much at all (if any) before a summer storm.
There are reasons that summer storms are different from winter storms. There are different patterns to watch for in each. Today we are going to discover these patterns.
1. Use Science Process and Thinking Skills.
Invitation to Learn
Get two bowls. Put hot water in one and cold, ice water in the other. Get an empty plastic soda bottle that has strong sides. (Most bottled water bottles won't work because their sides are too weak.) Put a nine-inch balloon over the plastic bottle so that it hangs limply. Put the soda bottle in the hot water. Notice that the balloon rises. You can ask the students to give reasons why they think the balloon is rising. (The air in the bottle is getting hot. When air increases in temperature, the air molecules separate and need more room in the bottle. Some get pushed out the bottle and they go into the balloon. This is called expansion.) Now, take the soda bottle out of the hot water and put it in the cold water. Notice that the air goes back into the bottle. You can ask the students to give reasons why they thing the air went out of the balloon back into the bottle. (The air in the bottle is cooling down. When air decreases in temperature, the air molecules gather and sink and leave empty spaces in the bottle. This leaves room for the air in the balloon to go back down into the bottle. This is called contraction.) So, when air heats up it expands and rises and when it cools it contracts and sinks. (We can associate this with summer storms.)
Have a few quart jars ready with hot water in them to place on their desks. Have the same amount of small trays with ice in them and place them on their desks. Tell the students that there is hot water in the jars. Ask what the hot water is doing to the air. (It is heating the air, making it expand and rise.) Ask if there is anything else in the air in the bottle. (There is moisture in the air because the water is evaporating.) Tell them to put the tray of ice on top of the bottle. Ask them to predict what they think will happen to the air in the bottle with the ice on top. (The moist air will hit the bottom of the ice tray and form moisture on the bottom of the tray. Water may condense on the side of the bottle. A small cloud will form near the top of the bottle next to the ice tray.) (We can associate this with winter storms.)
Tell them that today we are going to set up a couple experiments that show the patterns of these summer and winter storms. One experiment will show how a winter storm forms and the other experiment will show how a summer storm forms. As we observe these experiments we will be able to watch for patterns.
Part One: Winter Storm Simulation
In real life most winter storms come in from the north. They bring with them cold air, low pressure, and generally moist air. This is usually a huge storm system that stretches the width of Utah. When it comes in it usually travels across the whole state and continues west. When this low pressure is approaching us from the north, winds begin to blow from the south since the pressure is higher in the south than the low pressure coming in. The wind coming in from the south is warmer and will raise our temperatures up many degrees. As the warm air approaches the low pressure, the air rises up and quickly expands and then cools. The moisture in the cooled air turns into clouds. As these clouds approach us, they could produce snow. It could drop between an inch to two feet of snow. The wind generally dies down but the snow keeps coming until the storm system passes over us. Afterward there is a lot of cold air behind it that can linger on for days.
Part Two: Summer Storm Simulation Bottle
In real life, most summer storms come in from the south because the air pressure in Utah is a little less than in Arizona a New Mexico. As the winds move in from the south it can bring in moisture from the Pacific Ocean. As the hot air in Utah is rising because of convection currents it creates a low pressure in the upward current. The winds that come in from the south carrying moisture get caught in this convection current and move up. As the moist air moves up it expands. When the air expands it cools turning the moisture into a cloud. As more and more air comes in, the cloud gets bigger and bigger turning it into a huge cumulonimbus cloud. These clouds can rise up as far as 25,000 feet. They are also known as thunderheads. These are the clouds that cause thunder and lightning, produce hail and/or heavy rainfall, and violent winds. The violent winds are caused by the air rushing into the low pressure of the convection current. The huge storm clouds gradually move on. The storm turns into a summer rain caused by the lingering clouds behind the storm clouds. It will rain less and less and the thunder and lightning can only be heard and seen off into the distance. The storm leaves behind it cooler, comfortable air.
Black, R. (2005). Why demonstrations matter. Science and Children, Vol. 44 (Number 1), page 56.
It is still a good practice to have teacher-centered demonstrations in the classroom. Children get excited when they see unfamiliar objects in front of them that they know are going to part of a science experiment. Careful planning and questions techniques give the teacher more control for the students to understand the results.
Bransford, J.D., Brown, A.L., & Cocking, R. R. (Eds). (1999). How people learn: brain, mind, experience, and school. Washington, DC: National Academy Press
Hands-on learning provides the students with kinesthetic, auditory, and visual learning. As students perform hands-on tasks, they make learning happen for themselves. They learn quickly from their experiences. They begin to make a connection to their world. As this approach in being taught the students learn through the process of inquiry. The teachers ask many questions during science lessons to make students thinking process complete.