2. http://www.brainpop.com/science/weather/weather/ BRAINPOP VIDEO

3. The weather forecast that helped you plan activities for this week was probably made by a meteorologist. A meteorologist is a person who studies the weather. Meteorologists need many kinds of data before the weather can be predicted.

4. When you step outdoors, the air temperature may be the first weather condition you notice. In fact, you probably dressed a certain way to be comfortable at that temperature. If the air temperature is around 15°C you might wear a sweater.

5. The atmosphere is the thin layer of air that surrounds the earth. The troposphere is the layer that is closest to the earth. This is where most weather occurs. The stratosphere is the layer right above the troposphere and is just above where most weather occurs. ATMOSPHERE

6. An air mass is a large body of air that has about the same temperature and moisture throughout. An air mass forms when a large body of air stays in the same place for several days. AIR MASS

7. Humidity is the amount of water vapor in the air. Which means the higher the number, the more water vapor there is in the air. This means storms are near. The lower the humidity number means there is less chance of rain because there is not enough water vapor in the air to form clouds. HUMIDITY

8. A cold weather front is defined as the changeover region where a cold air mass is replacing a warmer air mass. Cold weather fronts usually move from northwest to southeast. The air behind a cold front is colder and drier than the air in front. When a cold front passes through, temperatures can drop more than 15 degrees within an hour. FRONTS

9. A warm weather front is defined as the changeover region where a warm air mass is replacing a cold air mass. Warm fronts usually move from southwest to northeast and the air behind a warm front is warmer and moister than the air ahead of it. When a warm front passes, the air becomes noticeably warmer and more humid than it was before. FRONTS

10. Meteorologist place all of their data that they collect on to a weather map. By means of certain symbols, a single weather map can indicate atmospheric conditions above a large portion of the earth's surface. WEATHER MAP

11. Thermometers measure air temperature. Thermometers work because matter expands when heated. Most thermometers are closed glass tubes containing liquids such as alcohol. When air around the tube heats the liquid, the liquid expands and moves up the tube. A scale that shows the temperature is on, or attached to, the tube. THERMOMETER

12. A barometer measures air pressure. Air pressure presses down on the mercury forcing it up the glass tube. There is a scale attached to the glass tube. BAROMETER

13. An anemometer, like the one shown in the picture, measures wind speed. The cups catch the wind, turning a dial attached to the instrument. The dial shows the wind speed. ANEMOMETER

14. Read Science textbook page D23 and answer the questions. INDEPENDENT PRACTICE