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Air Pressure and Weather Your Shadow and the Sun..... ........... ......... 2 A Cubic Meter of Air ........... ........... ......... 3 The Magic Glass........ ........... ........... ......... 4 Air Pressure ... ........... ........... ........... ......... 5 Rubber Barometer ..... ........... ........... ......... 6 Bottle Barometer ....... ........... ........... ......... 7 Cooling by Evaporation......... ........... ......... 8 Cooling by Evaporation Alternative Experiment .. ........... ......... 9 Water Vapor in the Air.......... ........... ....... 10 Supplementary Information........ ....... 11 Sling Psychrometer.... ........... ........... ....... 12 Relative Humidity Table ........... ....... 13 Evaporation ... ........... ........... ........... ....... 14 Where do the Seasons Come From? . ....... 15 Understanding Weather......... ........... ....... 16 Cloud Types .. ........... ........... ........... ....... 18 Types of Weather Fronts ....... ........... ....... 19 Weather Maps ........... ........... ........... ....... 20 Dangerous Weather ... ........... ........... ....... 22 Tornado in a Bottle.... ........... ........... ....... 24 Weather Scavenger Hunt....... ........... ....... 25 Forecasting the Weather........ ........... ....... 26 Wind Chill..... ........... ........... ........... ....... 29 Temperature-Humidity Index ........... ....... 30 Wind Vane Instructions......... ........... ....... 32 Sling Psychrometer Instructions........ ....... 32 Record Temperatures, by State.......... ....... 33 Materials Needed....... ........... ........... ....... 35 Recording the Weather.......... ........... ....... 36 Your Shadow and the Sun Materials Needed: Volunteer, sunny sidewalk, chalk. Concepts: Your shadow changes with time of day and day of year. Activity: Pick a sidewalk location which will be sunny all day. Have your volunteer stand there. Trace the outline of the volunteer's feet and shadow with chalk. Measure the height of the shadow. Use a compass to measure the direction the shadow is pointing (foot to head). Repeat periodically throughout the day. Fill in the following table. Add more rows to the table if necessary. Time Length Direction Time Length Direction Special Care: Please write down any pitfalls you notice. Do any parts of this activity require special care? Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. The changes in the shadow as the sun moves through the sky are really surprising the first time you see them. Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. Further Investigation: Do this on different days during the year and compare the results. Make a graph of height versus time on a single day. Make a graph of maximum height versus time of year for a number of days during different seasons of the year. Make graphs of direction versus time for different seasons and compare. 2 A Cubic Meter of Air Materials Needed: Twelve meter-long sticks, duct tape. Concepts: The metric system; volume, density, and mass. Activity: A cube has 12 edges. Take 12 meter-long sticks and duct tape them together into a cube a meter on each side. Inside is a cubic meter of air. How much does the cubic meter of air weigh? If I wrapped it in a baseball-sized ball and threw it to you, how would you react? Would it be like catching a feather? A baseball? A bowling ball? Duct tape together objects of appropriate mass and let your class experience first-hand what a cubic meter of air "feels" like. Special Care: Please write down any pitfalls you notice. Do any parts of this activity require special care? Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. 3 The Magic Glass Materials Needed: Thin cardboard (index card or piece of file folder) or paper, glass or other containers with smooth openings, plastic "glass," water, daring volunteer. Concepts: Air exerts pressure. Activity: Try both of these similar experiments. Please notice the third item below, and someone remind me about it if I forget. z Fill the glass to the brim with water. Place the piece of cardboard or paper over the glass. Turn the glass upside down, holding the cardboard in place with your hand. Hold the glass directly over your daring volunteer's head. Take away the hand holding the cardboard. Explain the results. z Make a small hole in the side of the plastic "glass." Repeat the first experiment, once with the hole covered by your finger and once with it uncovered. z Set aside a glass of water. We will need some room temperature water for later lessons. Special Care: Please write down any pitfalls you notice. Do any parts of this activity require special care? This really works, but unless you like living dangerously, practice over a sink first. Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. We often forget we are living at the bottom of a sea of air. The air exerts a lot of pressure. The upward pressure of the air on the paper is enough to hold up a tall column of water. The water remains in the glass because the downward pressure of the is not transmitted through the rigid glass. Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. Further Investigation: Experiment with a variety of different containers of different volumes and different sized openings. Experiment with the glass completely filled and with a range of water levels inside. 4 Air Pressure Materials Needed: Large pan or tub, drinking glass or jar or bottle, straw, water. Concepts: Air exerts pressure. Activity: z Submerge the glass in the large pan of water. Be sure the glass is filled with water. Lift the glass up with the mouth down, until the glass is nearly out of the water. Record and explain your observations. z Immerse a soda straw in water. Hold a finger over one end of the straw. Lift the straw out of the water. What happens? Remove your finger from the end of the straw. What happens? Explain. Special Care: Please write down any pitfalls you notice. Do any parts of this activity require special care? Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. This is a less-exciting variation on the previous activity. fascinating for children. It's "old stuff" to adults, but Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. 5 Rubber Barometer Materials Needed: Wide mouth jar, large balloon, strong rubber band, straw, wooden match, tape or glue, index card or other heavy paper. Concepts: We can construct a simple instrument to measure air pressure. Activity: 1. Cut the balloon and stretch it across the mouth of the jar. The balloon should form a perfect air seal and be flat across the mouth. You can secure the balloon with the rubber band. 2. Tape or glue the match across the edge of the jar, so that both ends are resting on the rim of the jar. 3. Cut one end of the straw into a point. Tape or glue the other end to the center of the balloon and let the straw rest on the match. The point of the straw will extend well beyond the edge of the jar. 4. Prop the index card or heavy paper vertically and position it next to the pointed straw tip. Mark the position of the straw tip. Calibrate your barometer by getting barometric pressures from the local radio or television station. Periodically mark and calibrate the straw position. Special Care: Please write down any pitfalls you notice. Do any parts of this activity require special care? The barometer must be placed in an area where the temperature stays fairly constant (why?-because a change in air temperature will inflate/deflate the balloon and give a false reading). The balloon eventually leaks and invalidates your calibrations. Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. With practice, you can easily do this activity. It's very difficult, if not impossible, to get meaningful readings from the "barometer," but often you can observe changes which do seem to be correlated with the actual weather. Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. Further Investigation: How is an aneroid barometer made. (This lesson is actually a variation of the aneroid barometer, which many elementary science texts discuss.) 6 Bottle Barometer Materials Needed: Graduated cylinder, pan of water. Concepts: Another instrument to measure air pressure. Activity: Follow this procedure to make a "bottle" barometer: 1. Fill the graduated cylinder most of the way with water and invert it with the opening under the surface of the water in the pan. By now, you should be able to explain why water remains in the cylinder. 2. Wait until the bubbles are mostly gone. 3. Measure the height of water (above the level of the water in the pan) in the cylinder. Get the atmospheric pressure reading from a local radio or television station or some other reliable source. The height of water in the cylinder corresponds to this pressure. 4. Periodically calibrate your barometer by measuring the height of water and getting the atmospheric pressure from your reliable source. The readings are usually given as the height in inches of a column of mercury that is supported by the atmosphere. Eventually you should be able to create a table like this: Barometric Pressure (inches) Height of Water in Cylinder (units?) 5. When you have calibrated a large number of readings, you should be able to use your "bottle" barometer to obtain the barometric pressure. Special Care: Please write down any pitfalls you notice. Do any parts of this activity require special care? Keep the water level in the pan always the same, or else be sure to measure the actual height of the water column in the cylinder. Be sure to always follow the same procedure to measure the water height. Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. This barometer also doesn't "really" work. That's why a good weather station should have a real barometer. Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. 7 Cooling by Evaporation Materials Needed: Thermometer, watch, cardboard, eyedropper, room temperature water. Concepts: Energy is required to turn liquid water into water vapor. Activity: 1. Record the temperature reading of your thermometer. 2. Predict what will happen to the temperature reading if you fan the thermometer with a piece of cardboard for 30 seconds. Record your prediction here: . 3. Fan the thermometer for 30 seconds. Record the temperature. 4. Predict what will happen to the temperature reading if you drop a drop of water on the thermometer and wait 30 seconds. Record your prediction here: . 5. Make sure your thermometer is reading room temperature. Use your eyedropper to put a drop of water on the bulb of the thermometer. Wait 30 seconds. Record the temperature. 6. Predict what will happen to the temperature reading if you fan the wet bulb of the . thermometer for 30 seconds. Record your prediction here: 7. Make sure your thermometer is reading room temperature. Put a drop of water on the bulb and fan the wet bulb for 30 seconds. Record the temperature. 8. Fill in the chart below. Condition Temperature Explanation Initial thermometer reading. Temperature after fanning for 30 seconds Temperature after 30 seconds with drop of water on bulb. Temperature after fanning 30 seconds with water on bulb. Special Care: Write down any pitfalls you notice. Do any parts of this activity require special care? Don't touch the thermometer bulb. Even a drop of water squeezed out of a slightly damp paper towel can be warmed by your touch. Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. The results of this activity can vary a lot. Fanning a dry bulb with room-temperature air should have no effect; fanning a wet bulb should cool it off. Our intuition says fanning the dry bulb should cool it off, but fanning only helps evaporate water on the bulb. If there's no water, there's no cooling. People's preconceived ideas about the probable results seem to have a direct influence on their measurements in this activity. Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. 8 Cooling by Evaporation--Alternative Experiment Materials Needed: Four thermometers, watch, cardboard, eyedropper, room temperature water. Concepts: Energy is required to turn liquid water into water vapor. Activity: 1. Predict what would happen to a temperature reading if you fanned a thermometer with a piece of cardboard for 30 seconds. Record your prediction here: . 2. Predict what would happen to a temperature reading if you dropped a drop of water on the thermometer and waited 30 seconds. Record your prediction here: . 3. Predict what would happen to a temperature reading if you fanned the wet bulb of a . thermometer for 30 seconds. Record your prediction here: 4. Put two thermometers aside, side-by-side, where they won't get fanned. Put two thermometers side-by-side, where they will get fanned. Record all four thermometer readings. 5. Do the following as quickly as you can: put a drop of water on one of each pair of thermometers. Note the time. Fan two of the thermometers for 30 seconds. Stop fanning and record all four temperatures. 6. Fill in the chart below. Condition Starting Ending Change Explanation Temperature Temperature Unfanned dry thermometer. Unfanned wet thermometer. Fanned dry thermometer. Fanned wet thermometer. Special Care: Please write down any pitfalls you notice. Do any parts of this activity require special care? Don't touch the thermometer bulb. Even a drop of water squeezed out of a slightly damp paper towel can be warmed by your touch. Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. This is an alternative presentation of the previous activity. Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. 9 Water Vapor in the Air Materials Needed: Thermometer, "tin" can, ice. Concepts: The amount of water the air can hold varies with temperature. Activity: 1. Partially fill a shiny "tin" can with room temperature water. Place a thermometer in the water and wait until the temperature as indicated by the thermometer has more or less stabilized. 2. Put some ice in the can. Keep the thermometer in the water (avoid contact with the ice). You can slowly stir the water with the thermometer to ensure the temperature is uniform throughout. 3. Watch the can. Record the temperature at the first instant at which you see condensation on the can. 4. Use the table on the next page to determine the relative humidity. Special Care: Please write down any pitfalls you notice. Do any parts of this activity require special care? Don't breathe on the can, but watch very carefully because it is easy to miss the first instant of condensation. Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. This activity lets you measure the relative humidity (see the next page). However, you need to record the temperature at the first instant of condensation. In a class of 10 groups of 2, typically only one or two groups are successful. If you wait too long, the can cools too much, the "after" temperature reading is too low, and the calculated relative humidity is too low. You might want to just use this as an activity to observe the condensation associated with temperature change, and not try to calculate the relative humidity. Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. 10 Water Vapor in the Air Supplementary Information The table below gives the amount of water in saturated air at a given temperature. For example, at a temperature of 30°C, saturated air holds 27.69 grams of water for every kilogram of air. Air at 30°C holding 27.69 grams of water per kg of air cannot hold any more water; the relative humidity of that air is 100%. The dew point is the temperature at which dew begins to form. Hot air can hold more water than cold air. If hot, moist air is cooled, eventually a temperature is reached where the air can no longer hold all the water present, and the water vapor condenses as dew. For example, if air at 30°C holding 14.95 g/kg of water is cooled, when the temperature reaches 20°C the air is holding as much water as possible. If the air is cooled lower than 20°C, water will condense out as dew. The relative humidity is the amount of water the air actually holds compared to the maximum amount the air could possibly hold. For example, suppose the temperature is 25°C (a hot day) and the air is holding 16 g/kg of water. The air could hold as much as 20.44 g/kg of water, so the relative humidity is (16/20.44)x100%=78%. To determine the relative humidity, put water into a shiny tin can. The water should be at or above air temperature. Measure the air temperature. Put the thermometer in the can of water. Add ice to the water. Observe both the temperature and the outside of the can. The dew point is the temperature at which water first begins to condense on the outside of the can. You need to watch carefully, because it's easy to miss the beginning of condensation. You might want to stir the water gently so the thermometer and can temperatures are the same. The humidity is the amount of water vapor corresponding to the dew point temperature divided by the amount of water vapor corresponding to the air temperature, times 100%. For example, if the air temperature is 25°C and the dew point is 18°C, the relative humidity is (13.14/20.44)x100%=64%. Pitfalls: it is very easy to miss the first condensation of water vapor on the can. If you miss it, the ice will continue to cool the water and thermometer, so you will read a temperature which is too low. That will make your calculated relative humidity too low. Also, the water vapor condenses on the can and not the thermometer, so it is important to make sure that the thermometer accurately reads the can temperature. Temp Grams Temp Grams Temp Grams Temp Grams (°C) /kg (°C) /kg (°C) /kg (°C) /kg 48 78.66 31 29.38 14 10.13 -3 3.07 47 74.31 30 27.69 13 9.48 -4 2.85 46 70.21 29 26.06 12 8.87 -5 2.64 45 66.33 28 24.52 11 8.29 -6 2.44 44 62.64 27 23.08 10 7.76 -7 2.26 43 59.15 26 21.72 9 7.26 -8 2.09 42 55.86 25 20.44 8 6.76 -9 1.93 41 52.75 24 19.20 7 6.31 -10 1.79 40 49.81 23 18.04 6 5.89 -11 1.65 39 47.00 22 16.94 5 5.50 -12 1.53 38 44.34 21 15.92 4 5.12 -13 1.41 37 41.84 20 14.95 3 4.76 -14 1.30 36 39.48 19 14.04 2 4.43 -15 1.20 35 37.25 18 13.14 1 4.13 -16 1.10 34 35.10 17 12.32 0 3.84 -17 1.01 33 33.08 16 11.55 -1 3.56 -18 0.93 32 31.18 15 10.83 -2 3.31 -19 0.85 11 Sling Psychrometer Materials Needed: shoestring. Two thermometers, dowel rod, screw, washers, eyedropper, water, Concepts: Another way to measure humidity. Activity: 1. Drill a small hole in a 6-inch length of a dowel rod. Attach a thermometer with a screw. Use washers to allow the thermometer to swing freely. 2. Slide a short length of shoelace over the bulb of the thermometer. Use an eyedropper to add a few drops of water to the shoelace. You have made a "wet-bulb" thermometer. 3. Slowly spin the thermometer. Check the temperature periodically. It will go down. Why? Record the temperature when it stops dropping. 4. Record the temperature of the dry-bulb thermometer. (The other one). Then use the table on the next page to determine the relative humidity. Special Care: Please write down any pitfalls you notice. Do any parts of this activity require special care? Make sure both thermometers read the same when you start. Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. For simplicity, this activity says to sling only one thermometer around. In a real sling psychrometer, two thermometers are used, one with a dry bulb and one with a wet bulb. Nevertheless, the results from this activity tend to be reasonably accurate. The table on the next page is only good for high-humidity situations. Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. 12 Relative Humidity Table for Sling Psychrometer Dry (°C) Difference Between Wet- and DryBulb readings (°C) 1 2 3 4 5 Dry (°C) Difference Between Wet- and DryBulb readings (°C) 1 2 3 4 5 10 88 77 66 55 44 20 91 83 74 66 59 11 89 78 67 56 46 21 91 83 75 67 60 12 89 78 68 58 48 22 92 84 76 68 61 13 89 79 69 59 50 23 92 84 76 69 62 14 90 79 70 60 51 24 92 84 77 69 62 15 90 80 71 61 53 25 92 84 77 70 63 16 90 81 72 63 54 26 92 85 78 71 64 17 90 81 72 64 55 27 92 85 78 71 65 18 91 82 73 65 57 28 93 85 78 72 65 19 91 82 74 65 58 29 93 86 79 72 66 13 Evaporation Materials Needed: Jars, lids, pans, water. Concepts: Water evaporates. Rate of evaporation depends on a variety of conditions. Activity: z Take two identical jars with airtight lids, such as baby food jars. Fill both with water and seal one with the lid. Aluminum foil and a rubber band could be used as a seal if you don't have jars with lids. Place the jars side-by-side and observe the water levels for a period of several weeks. Explain the results. z Fill two identical jars with water. Place one in a warm, sunny location, and another in a cool, dark location. Observe the water levels over a period of several weeks. Explain the results. For this experiment, wide, flat pans with large surface areas will accelerate the effect. Special Care: Please write down any pitfalls you notice. Do any parts of this activity require special care? Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. It takes energy to evaporate water. It also helps if the water has somewhere to go, because, as you learned in the previous activities, air can't hold very much water. You might try measuring rates of evaporation for different liquids. Does soda evaporate faster than water? Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. 14 Where do the Seasons Come From? Materials Needed: Globe, flashlight, index card, tape, tape measure. Concepts: Why it is hot in the summer and cold in the winter. Activity: 1. Cut a square opening in the index card and tape it over the front of the flashlight. The light should produce a square shape rather than a round one. Mount the flashlight on a stack of books or something so that it can shine on the globe. Shine the light on the globe near Missouri with the globe straight up. Have your students measure the size of the light on the globe and figure the area. 2. Now tilt the globe at an angle and shine the light at the same area. Again, have the students figure the area covered. 3. Your students should observe that in the winter the same amount of sunlight covers a much larger area. 4. Here's a simpler version. Shine a flashlight straight at the blackboard. Trace an outline around the "bright" circle of light. Then tilt the flashlight and trace around the bright area. Then ask: does the same amount of light cover a larger or smaller area when the blackboard and light source are tilted relative to each other? Would the illuminated area heat up faster or slower when they are tilted. Special Care: Please write down any pitfalls you notice. Do any parts of this activity require special care? Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. Further Investigation: The earth tilts about 23.5° on its axis. Is the earth closer to the sun in our winter or in our summer? Answer: it's closer in the winter! Here's an interesting idea, especially if you need to teach about graphing. The Weather Channel (Channel 36 in Rolla) gives the normal high and low temperature and sunrise and sunset times every day. Assign students the task of recording these times and temperatures and bring them to class. There are lots of things you could graph: daily high and low, daily sunrise and sunset, number of hours of "day" every day, etc. At the end of this set of handouts is an example of such a graph for St. Louis in 1986. 15 Understanding Weather A Brief Introduction to Weather Fundamentals As They Pertain to the Northern Hemisphere Uneven heating of the earth's surface causes convection currents (wind). Equatorial regions receive more of the sun's rays than polar regions. If the earth were not rotating, its air circulation pattern would look like this: In the northern hemisphere, the earth's rotation causes flowing air to curve to the right. This is called the "Coriolis force." Air flowing from the equator curves until it flows westerly at about 30° latitude. Air flowing from the poles curves until it becomes easterly at about 60° latitude. This results in the confusing (to my eyes, anyway) circulation patterns often shown in your textbooks. Since air is flowing into the 30° and 60° latitudes, it piles up there, giving rise to belts of high pressure air circling the earth. The result is an unstable situation. Large masses of cold dry air try to break through the northern high pressure belt and plunge toward the tropics. Large masses of warm moist air try to break through the southern high pressure belt and carry warm air northward. The result is a never ending battle between the forces of cold and warm air in the mid-latitudes where we live. Go out on some thunderstormy evening to watch this battle. In the winter, cold outbreaks tend to come from the colder north. In the summer, cold outbreaks tend to originate from cool water surfaces. Thus, our winter storms come from Canada, and our summer storms come from the Pacific. 16 Wind circulates clockwise around high pressure areas, due to the Coriolis force. The stormy low pressure areas in between have a counterclockwise air rotation. The jet stream is a high altitude river of very strong wind moving from west to east. In the summer, the jet stream migrates north towards Canada as the warm tropical air pushes north. A jet stream pattern like this means hot weather: In the fall and spring, a jet stream pattern with sharp kinks in it means you should expect stormy outbreaks near the kinks. A bulge in the jet stream like the one below during the winter months means cold Canadian weather: 17 Cloud Types Materials Needed: Clouds, handout. Concept: The different types of clouds. Activity: There are four basic "families" of clouds: high clouds, middle clouds, low clouds, and clouds with extensive vertical development. The first three families are subdivided into the way they are formed: clouds formed by vertical currents in unstable are cumulus (accumulation or heap); clouds formed by the cooling of a stable layer are stratus (stratified or layered). The prefix nimbo or the suffix nimbus means raincloud. The suffix fractus, as in cumulus fractus, means fragmentary clouds. High clouds: cirrus, cirrocumulus, and cirrostratus. Middle clouds: altostratus, altocumulus, and nimbostratus. Low clouds: stratus, stratocumulus, and fair weather cumulus. Clouds with extensive vertical development: towering cumulus and cumulonimbus. Special Care: Please write down any pitfalls you notice. Do any parts of this activity require special care? Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. 18 Types of Weather Fronts Cold Fronts A cold front occurs when cold air pushes into a region of warmer air. Remember that cold air can hold less water than warm air, so cold fronts bring dry air. Also remember that warm air rises, so the cold air pushes in underneath the warm air. Warm Fronts A warm front occurs when warm air pushes into a region of cooler air. Warm air is moist, and rises above the cold air. The warm air can be either stable or unstable. Stationary Fronts A stationary front occurs when warm and cold air meet but do not move. Occluded Fronts Occluded fronts occur when three types of air meet; e.g. cold air, warm stable air, and warm unstable air. Weather associated with occluded fronts can be very complex. The Weather Associated With Fronts The weather associated with both cold and warm fronts depends on whether the warm air is stable or unstable. A cold front underrunning warm, moist, stable air brings stratified (layered) clouds and continuous precipitation. A cold front underruning warm, moist, unstable air brings cumulus clouds with possible showers and thunderstorms. 19 Weather Maps Materials Needed: Weather map, marking pens. Concept: Newspaper weather maps can help you teach the weather. Activity: Weather maps show fronts, high and low pressure systems, precipitation, and temperatures. Cut out some newspaper weather maps and glue them to the next page. Trace the cold fronts with blue markers, trace the warm fronts with red markers, draw blue circles around low pressure systems, and draw red circles around high pressure systems. Color in green or white (depending on the season) the areas of precipitation. Feel free to use different color schemes if you want. Do this several days in a row and see if you can follow how the weather has developed. Could you look at the maps for the last couple of days and predict tomorrow's weather? Special Care: Please write down any pitfalls you notice. Do any parts of this activity require special care? Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. 20 Internet Weather Maps Some sites to visit (please let me know if any of these links no longer work): http://www.weather.com/weather/us/states/Missouri.html choose from a list of Missouri cities http://www.weather.com/weather/us/cities/MO_Rolla.html Rolla’s forecast and regional radar http://www.intellicast.com/weather/sgf/radar/ Springfield radar http://www.intellicast.com/weather/cou/radar/ Columbia radar http://www.intellicast.com/drdew/ Dr. Dewpoint http://weathereye.wokrtv.com/index.html station WOKR weather page 21 Dangerous Weather Materials Needed: Class discussion. Concept: What to do in dangerous weather. Activity: Discuss the following types of dangerous weather which Missourians are likely to encounter: • heat waves • cold waves • thunderstorms • lightning • tornadoes • floods. What safety precautions should you take for each type of weather. Which type of weather is the greatest threat to you? Special Care: Please write down any pitfalls you notice. Do any parts of this activity require special care? Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. Heat is the biggest killer. See the fact sheet on the next page. Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. 22 Dangerous Weather Grim Facts No matter where you live, you aren't safe from the weather: Tornadoes kill about 100 Americans per year, including about 4 Missourians. Lightning kills about 150 Americans per year. Floods kill 100-200 Americans per year. Heat is directly responsible for the deaths of about 450 Americans per year, and indirectly triggers many other deaths (e.g., heart attacks in the elderly). Winter storms kill about 100 Americans per year. The 1980 heat wave in the central United States hit Missouri the hardest. Missourians and cost Missouri about $1,500,000,000. It killed 311 Some Weather Records Highs: 136° in Libya, September 13, 1922. 134° in Greenland Ranch, CA, July 10, 1913. On February 21, 1918, in Granville, ND, the temperature rose 83° (from -33° to 50°) in 12 hours. On January 22, 1943, in Spearfish, SD, the temperature rose 49° (from -4° to 45°) in two minutes! Lows: -126.9°F in Vostok, Antarctica, August 24, 1960. -79.8°F in Prospect Creek Camp, Alaska, January 23, 1971. -69.7°F in Rogers Pass, Montana, January 20, 1954. On January 23-24, 1916, in Browning, Montana, the temperature fell 100° (from 44° to -56°) in 24 hours. On December 24, 1924, in Fairfield, Montana, the temperature fell 84° (from 63° to -21°) in 12 hours. On January 10, 1911, in Rapid City, SD, the temperature fell 47° (from 55° to 8°) in 15 minutes. (How would you like to get on the school bus in 55° weather, wearing a light jacket, and get off 15 minutes later in 8° weather?) Missouri: 118°F in Warsaw and Union, July 14, 1954. -40°F in Warsaw, February 13, 1905. Did you know that the all-time record high temperature in Alaska is the same as the all-time record high temperature in Hawaii? If you find these facts intriguing, get The Weather Almanac, by James A. Ruffner and Frank E. Bair, published by Gale Research Company, Detroit, Michigan. 23 Tornado in a Bottle Materials Needed: Two 2-liter soda bottles, tygon tubing, washer, water. Concept: A neat, but not particularly educational, display. Activity: Fill a 2-liter soda bottle with water. Attach to another 2-liter bottle with the tygon tubing with the washer in the center. Can you make a vortex in the bottle? Special Care: Please write down any pitfalls you notice. Do any parts of this activity require special care? The principal is guaranteed to walk in just as the bottles come apart. Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. Twirl the bottles gently around to get the vortex started. Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. Further Investigation: You can liven up the tornado with Monopoly houses or small figures. Does this really have anything to do with a tornado? 24 Weather Scavenger Hunt Materials Needed: Your imagination. Concepts: How weather affects everyday life. Activity: Divide into teams. Each team has a given amount of time to find as many as possible of the following: something bending toward the sun something hiding from sunshine something that may become part of a cloud something left by the rain something that tells you the wind is blowing a place where icicles might form a sign of an animal used to "predict" weather sign of an animal that likes rain a place where weather has damaged a building a place to go where it's cool a bad place to seek shelter during a storm a place that gets little sunshine a good place to seek shelter during a tornado something that bends in the wind something that won't bend in the wind a sign of lightning damage something that reflects lots of sunlight a good windbreak something that absorbs lots of sunlight a place where rain has moved the soil something that will soak up rain something that makes rain splatter something that protects people from rain something shaped by wind or water something the color of the sky something the color of snow something that smells better after a rain shower something that would melt snow something that uses sunlight or wind or water to work Special Care: Please write down any pitfalls you notice. Do any parts of this activity require special care? Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. Further References: This idea came from Ranger Rick's NatureScope, "Wild About Weather." 25 Forecasting the Weather Materials Needed: Weather readings, weather forecasting charts. Concepts: What goes into a weather forecast. Activity: Following this page are two forecasting handouts. The first one is titled "Be Your Own Forecaster." A barometer reading and wind direction are all that are needed to give you a weather forecast. The same handout also gives the Beaufort wind scale. The second one is titled "Weather by the Chart." You need to know the clouds in addition to the winds and barometer reading. Simply add the numbers for "Clouds," "Winds," and "Pressure," and look up the appropriate forecast under "Weather Forecaster." Here are some things you can do with these forecasting charts: 1. Guess what the weather will be. Forecast the weather using these charts. Compare your guesses and forecasts over a period of time. 2. Forecast the weather using these charts. Record TV or radio forecasts. Clip out the newspaper forecasts. Compare the various forecasts over a period of time. Use the various forecasts to have your students tell you what they should wear to school the next day. Then see what they actually wear. Special Care: Please write down any pitfalls you notice. Do any parts of this activity require special care? Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. 26 Barometer 30.10 to 30.20 and steady 30.10 to 30.20 and rising rapidly 30.10 to 30.20 and falling slowly 30.10 to 30.20 and falling rapidly 30.20 and above and steady 30.20 and above and falling slowly 30.10 to 30.20 and falling slowly 30.10 to 30.20 and falling rapidly 30.10 to 30.20 and falling slowly 30.10 to 30.20 and falling rapidly 30.10 and above and falling slowly Be Your Own Forecaster Wind Direction Forecast SW to NW fair with slight temperature changes for 1 to 2 day SW to NW fair followed within 2 days by warmer and rain SW to NW warmer with rain in 24 to 36 hours SW to NW warmer with rain in 18 to 24 hours SW to NW continued fair with no decided temperature change slowly rising temperature and fair for 2 days rain within 24 hours SW to NW S to SE S to SE SE to NE SE to NE E to NE 30.10 and above and falling rapidly E to NE 30 or below and falling slowly 30 or below and falling rapidly SE to NE SE to NE 30 or below and rising slowly S to SW 29.80 or below and falling rapidly S to E 29.80 or below and falling rapidly 29.80 or below and rising rapidly E to N going to W wind increasing in force with rain within 12 to 24 hours rain in 12 to 18 hours increasing wind with rain within 12 hours in summer with light winds, rain may fall for several days; in winter, rain within 24 hours in summer, rain probable within 12 hours; in winter, rain or snow, with increasing winds, will often set in, when the barometer begins to fall and the wind sets in from the NE rain will continue 1 to 2 days rain with high wind, followed within 24 hours by clearing and cooler clearing within a few hours, and continued fair for several days severe storm of wind and rain or snow imminent, followed within 24 hours by clearing and colder severe NE gales and heavy rain/snow followed in winter by cold wave clearing and colder 27 Weather by the Chart Add the numbers for "Clouds," "Winds," and "Pressure," and look up the appropriate forecast under "Weather Forecaster." To address the core competencies, you should use the various forecasts to have your students tell you what they should wear to school the next day. Then see what they actually wear. Clouds Cumulonimbus .......... 1......... Stratus ........... ........... 2......... Low, thickening......... 3......... High clouds ... ........... 4......... Stratocumulus ........... 5......... Clouds rising . ........... 5......... Clear ........... ........... 6......... Cumulus ........ ........... 7......... Winds Pressure N 2......... NE 1......... E 1......... SE 1......... S 2......... SW 3......... W 3......... NW 4......... Variable3 ........... Calm 3............. Very low and dropping.......... 1 Low and dropping ..... ........... 2 Low and fluctuating... ........... 3 Average and dropping ........... 3 High and dropping..... ........... 3 Very high and dropping......... 4 Average, fluctuating .. ........... 5 Low, rising ........... ........... 6 Average and rising ........... 7 High and rising ........... 8 Very high and rising ........... 9 Weather Forecaster Forecast # Forecast 3......... .......... .............Heavy precipitation within six hours 4......... .......... .............Precipitation within 6-12 hours, little temperature change 5......... .......... .............Brief precipitation within 18 hours, rise in temperature 6 or 7.. .......... .............Precipitation within 24 hours, rise in temperature 8......... .......... .............Precipitation within 30 hours, no temperature change 9 or 10 .......... .............Increase in clouds 11....... .......... .............Little precipitation in next 24 hours 12....... .......... .............Winds with possible showers 13 or 14......... .............Immediate precipitation, then clearing and cooler 15....... .......... .............Showers or flurries, then clearing and cooler 16....... .......... .............Clearing in a few hours 17....... .......... .............Partly cloudy, no temperature change 18....... .......... .............Fair with little change in next 36 hours 19....... .......... .............Mostly fair with rising temperatures 20....... .......... .............Continued fair Clouds Add up some numbers and make a forecast: This activity was taken from Ranger Rick's NatureScope, "Wild About Weather." Winds Pressure Forecast 28 Wind Chill Wind speed, relative humidity, sunshine, and clothes worn all influence how cold a person feels outdoors. Also, different people may feel different amounts of "coldness" under the same conditions. Nevertheless, it is possible to define an objective measure of "coldness." Weather people define "coldness" by measuring how much heat is lost from water under given weather conditions. The lower the temperature or the stronger the wind, the faster heat is lost; for example, a cup of ice will freeze faster in 20° weather with 20 m.p.h. wind than it will with 10 m.p.h wind. If you make the reasonable assumption that heat is lost from exposed skin at a similar rate, then you have an objective measure of coldness. To see how "cold" you will feel under given weather conditions, read down the appropriate temperature column and across the appropriate wind speed row until you find the wind chill. Since this wind chill table doesn't list all possible temperatures and wind speeds, you may need to estimate the wind chill based on the numbers closest to the actual conditions. Wind Speed (mph) Wind Speed (mph) 4 5 10 15 20 25 30 35 40 45 4 5 10 15 20 25 30 35 40 45 45 45 43 34 29 26 23 21 20 19 18 0 0 -5 -22 -31 -39 -44 -49 -52 -53 -54 40 40 37 28 23 19 16 13 12 11 10 Wind Chill Equivalent Table Dry Bulb Temperature (°F) 35 30 25 20 15 35 30 25 20 15 32 27 22 16 11 22 16 10 3 -3 16 9 2 -5 -11 12 4 -3 -10 -17 8 1 -7 -15 -22 6 -2 -10 -18 -25 4 -4 -12 -20 -27 3 -5 -13 -21 -29 2 -6 -14 -22 -30 10 10 6 -8 -18 -24 -29 -33 -35 -37 -38 5 5 0 -15 -25 -31 -36 -41 -43 -45 -46 0 0 -5 -22 -31 -39 -44 -49 -52 -53 -54 -5 -5 -10 -27 -38 -46 -51 -56 -58 -60 -62 Dry Bulb Temperature (°F) -15 -20 -25 -30 -15 -20 -25 -30 -21 -28 -31 -38 -40 -46 -52 -50 -51 -58 -65 -72 -60 -67 -74 -81 -66 -74 -81 -88 -71 -79 -88 -93 -74 -82 -89 -97 -76 -84 -92 -100 -78 -85 -93 -102 -35 -35 -42 -64 -78 -88 -98 -101 -105 -107 -108 -40 -40 -47 -71 -85 -95 -103 -109 -113 -115 -117 -45 -45 -57 -79 -92 -103 -110 -116 -120 -123 -125 -10 -10 -15 -34 -45 -53 -59 -64 -67 -68 -70 29 Temperature-Humidity Index This Temperature-Humidity Index expresses the reaction of most people to summer weather conditions. (Of course, everybody responds diffently to different weather conditions at different times.) A temperature of 90 °F with a relative humidity of 60% gives an index of 83. This is not equivalent to a temperature of 83; instead, the number shows that nearly everybody would feel uncomfortable, and work efficiency would be on the verge of rapidly decreasing. Temp. (°F) 10 20 RELATIVE HUMIDITY (Percent) 30 40 50 60 70 80 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 62 63 63 64 64 65 65 66 66 67 67 68 68 69 69 70 70 71 71 72 72 73 73 74 74 75 75 76 76 77 77 78 78 79 79 63 63 64 64 65 65 66 66 67 67 68 69 69 70 70 71 72 72 73 73 74 74 75 75 76 76 77 78 78 79 79 80 80 81 82 63 64 64 65 65 66 67 67 68 68 69 70 70 71 72 72 73 73 74 75 75 76 76 77 77 78 79 80 80 81 81 82 83 83 84 63 64 65 65 66 67 67 68 69 69 70 71 71 72 73 73 74 75 75 76 77 77 78 79 79 80 81 81 82 83 84 84 85 85 86 64 65 65 66 67 67 68 69 70 70 71 72 73 73 74 75 75 76 77 78 78 79 80 81 81 82 83 83 84 85 86 86 87 88 89 64 65 66 67 67 68 69 70 71 71 72 73 74 74 75 76 77 78 78 79 80 81 81 82 83 84 85 85 86 87 88 88 89 90 91 65 66 67 67 68 69 70 70 71 72 73 74 75 76 76 77 78 79 79 80 81 82 83 84 85 85 86 87 88 89 90 91 91 92 93 65 66 67 68 69 70 71 71 72 73 74 75 76 77 78 78 79 80 81 82 83 84 85 86 87 87 88 89 90 91 92 93 94 94 95 90 100 66 67 68 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 84 85 86 87 88 89 90 91 92 93 94 95 96 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 few people feel uncomfortable about 1/2 of all people feel uncomfortable nearly everyone feels uncomfortable rapidly decreasing work efficiency extreme danger 30 101 102 103 104 105 106 107 108 109 110 80 80 81 81 82 82 83 83 84 84 82 83 83 84 84 85 85 86 87 87 84 85 86 86 87 87 88 89 89 90 87 88 88 89 90 90 91 92 92 93 89 90 91 91 92 93 94 95 95 96 91 92 93 94 95 96 96 94 95 96 96 96 31 Wind Vane Instructions Your weather kit contains the parts for a homemade wind vane. It consists of two triangles cut out of heavy-duty cardboard, a straw, a pencil, a pin, and a couple of beads. The triangles are stapled to the straw to make an arrow, and the arrow is attached to the pencil with the pin. The beads help reduce the friction. The arrow should balance as well as possible on the beads. If it is too heavy towards the head or tail, tape some small weights (paper clips would do) on the other side to help it balance. You can easily make your own wind vane if the one supplied doesn't work well. The wind vane can be mounted with the end of the pencil in a ball of play-dough or clay. Use your imagination to find better ways to mount the wind vane. It works reasonably well if you take some extra time "polishing" it. The wind direction is always given as the direction from which the wind is blowing. If the wind is from the north, you will feel the wind in your face if you stand facing north, and the wind at your back if you stand facing south. A compass is provided with the weather station so that you can determine wind direction. To use your compass, first determine which point of the needle (green or silver) points north. Then rotate the compass body so that the letter "N" is underneath the north-pointing needle. You can read off the other directions from the compass. Caution: the compass will read wrong if you hold it near magnets, objects containing iron or steel, or even another compass. Sling Psychrometer Instructions The sling psychrometer consists of two thermometers attached back-to-back to a dowel rod. One of the thermometers has a piece of cloth attached over its bulb. To measure relative humidity, record both thermometer readings, wet the cloth (after recording temperatures) and slowly swing the thermometers around using the dowel rod. Check the temperature periodically. It will go down. (Why?) Record the temperatures of both thermometers when the temperature of the wet-bulb thermometer stops dropping. Use the table follwing the sling psychrometer lesson plan (pages 11-12) to determine the relative humidity. The use of inexpensive thermometers leads to one complication. The thermometers are unlikely to read the same temperature even under identical conditions. If the wet and dry bulb temperatures are TW1 and TD1 at the start of the experiment, and TW2 and TD2 at the end of the experiment, look up in the table the relative humidity which corresponds to (T W1-TD1)-(TW2-TD2). 32 33 34 Materials Needed The following items are listed as materials needed: 12 meter sticks 2-liter soda bottles (two) balloon (large) cardboard chalk (sidewalk chalk is best) clouds dowel rod duct tape eyedropper flashlight glass, jar, or bottle globe graduated cylinder ice index card jars and lids marking pens pan or tub rubber band (strong) screw shoestring straw sunny sidewalk tape or glue tape measure “tin” can thermometers tygon tornado tube and washer washers watch water water (room temperature) weather maps weather tables wide mouth jar wooden matchstick Curriculum K: Tell why weather affects what we do and how we dress. First: Classify a set of seasonal activities according to the four seasons. Second: Describe metric readings from thermometers; describe the changes in the state of matter when the amount of heat/cold is increased or decreased; describe the length of a shadow produced by the sun’s changes during the day; measure daily temperature and precipitation during a one-month period; determine what to wear based upon personal observation and weather data; draw various types of clouds. Third: Measure the temperature of several substances; classify a set of seasonal activities according to the four seasons; identify safe and appropriate responses to emergencies. Fourth: Measure the temperature at which matter changes. Fifth: Identify the variables in an activity in which heat is increased or decreased in a given state of matter; identify kinds of weather that follow a high or low barometric reading; identify cumulus, stratus and cirrus clouds; identify weather instruments and their uses. Sixth: Classify cloud types into basic groups; relate seasons to the earth’s motion and tilt. 35 Recording the Weather Materials Needed: Weather table, weather information. Concepts: Recording the weather for a period of time. Activity: Fill out the weather tables on one of the following pages. The tables start out simple and get more complex. Take your pick or invent your own. Special Care: Please write down any pitfalls you notice. Do any parts of this activity require special care? Classroom Use: How would you use this activity in your classroom? Comments: Write down your comments on this activity. Suggested Grade Level: Show-Me Standards: Goals: 1-1, 1-2, 1-3, 1-4, 1-5, 1-8, 1-10, 2-1, 2-3, 2-7, 3-1, 3-2, 3-3, 3-5, 4-1, 4-6. Knowledge Standards: Math 1,2; Science 1,2,5,6,7; Communication Arts 1,4. 36 Weather Statistics Date Normal High Low Actual High Low Rainfall Sunrise Sunset 37 Weather Table Date Time Temp Wind Rain Clouds Pressure Humidity Forecast 38 Weather Record Current Conditions Forecast Actual Date/Tim e Temperature °F °C Pressure Hum. Precip. Wind Speed/Dir. Sky/ Clouds Today Next Few Days 39