GRADE: Fourth

CONTENT STANDARD: Earth and Space Science

CONTENT TOPIC: Meteorology

CONCEPT: Atmospheric conditions vary.

CONTENT OBJECTIVE: 4K2.00 To understand weather and the effect of changing atmospheric conditions

> INSTRUCTIONAL OBJECTIVES: The learner will:

2.01 name some conditions that change the weather.
2.02 define air masses, warm front, cold front, stationary front, occluded front, and low/high pressure.

I. Conditions that change weather
II. Definitions
A. Air masses
B. Warm front, cold front, stationary front, occluded front
C. Low pressure, high pressure

TN COMPONENT OF SCIENCE: Habits of Mind

TN GOAL:

To enable students to demonstrate ways of thinking and acting inherent on the practice of science; and to exhibit an awareness of the historical and cultural contributions to the enterprise of science.

3.2 ASSUMPTIONS - The recognition and the criticism of the validity of an argument through presentation of data and differentiation between fact and assumption in the preparation of an explanation for a natural phenomenon are vital parts of the scientific process.

3.2a Science is based upon suppositions derived from observations of natural phenomena.

BENCHMARK: Unknown or unobserved variables may lead to unanticipated results.

3.2c The critical assumptions behind any line of reasoning must be made explicit so that the validity of the position taken can be judged.

BENCHMARK: Prior learning must be accurate and free of incorrect assumptions.

3.2d The validity of an investigation cannot be accepted unless the complete investigation can be independently duplicated.

BENCHMARK: Scientific truths must be supported by data in conjunction with logical evaluations.

TIME REQUIRED:

30 minutes

Collection of weather maps from local newspaper

What if we were going to plan a class picnic on the playground for one day this week. What are some things we would need to consider before we picked a day? (response, Look for words indicating weather.) We would probably want to know which day would have the best weather for us to be outside. Today we will learn about weather and some conditions that make weather change.

There are several conditions that influence what our weather will be like. One is TEMPERATURE, which is how hot or how cold the atmosphere around us is. Thunderstorms, hurricanes, lightning, rain and wind are all factors of weather that we are familiar with. Out there are some other important factors that we've heard the weatherman talk about that we really may not understand. Some of these terms are air mass, warm front, cold front, stationary front, occluded front, and high or low pressure system. (Use weather maps to demonstrate)

An air mass has nearly horizontally uniform temperature and moisture conditions. This means that for a long distance, at the same altitude, the temperature will be the same. It may be hot air (Tropical mass) cold air (Polar mass) moist air (Maritime) or dry air (Continental). Weather forecasting is based on information about air masses, high-low pressure systems and the movements of fronts. Air masses travel east across the United States. Different air masses meet along the way, but they usually don't mix. The surface between the different masses is called a FRONT. The forward edge of a cold air mass is called a COLD FRONT. The forward edge of a warm air mass would be a WARM FRONT. Sometimes cold and warm air masses stay in one place for a while. They do not move. When they don't move, they are called STATIONARY FRONTS. This means the weather will not change for awhile. An OCCLUDED FRONT is caused when masses of cold air have raised a warm air mass from the ground.

Sometimes weather forecasters will say something about high pressure or low pressure. These pressure areas are important to weather forecasters because certain kinds of weather can be expected with each kind of pressure area. Because cool air is heavier than warm air, the barometric pressure would go up when a cold air mass moved in. The weather in a high pressure area is usually fair. Most of the time high pressure means no clouds and fair weather. Because warm air is lighter then cool air the air moving up would make a low pressure area. This also makes clouds. Most of the time, a low pressure area means bad weather.

All of the above affects the temperature. During all of this, there would continue the cycle of water vapor (Water in the air as gas) evaporation (Water that can be seen, becoming water that cannot be seen) and condensation (Water that cannot be seen, becoming water that can be seen).

(Divide class into groups of four. Give each group a one week set of newspaper weather maps.) Study daily weather maps showing a high pressure area and a low pressure area. Read the daily weather forecasts for the days before and after each pressure goes by. Study the daily weather maps until it looks like a high or low pressure area is approaching where you are. Make your own forecast.

Pretend you are the meteorologist on the 10:00 news and give your forecast tot he class using your maps for aids.

This is the time this file has been accessed since 07/01/97.

The University of Tennessee at Martin is not responsible for the information or views expressed here.

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