Day 33 When we tried to make a cloud form in a soda bottle, we had to add a burning match. What did the burning match do? It released smoke, which is made up of tiny particles. Water vapor molecules need a surface to condense on, and the smoke particles provided a lot of tiny surfaces. What is the atmosphere? the layer of air that surrounds Earth In which layer does most of Earth's weather happen? in the troposphere; the lowest layer, where we live 1

Weather Balloons Investigation 6, Part 5 Water in the Air

Weather Balloons Meteorologists can get information about air in the troposphere by sending up weather balloons. They carry radiosondes, which have instruments for measuring air pressure and temperature, wind speed and direction, and relative humidity. Watch the Weather-Balloon Video. Daily Warm-Up Exercises 3

Video Discussion Why do meteorologists use helium or hydrogen in their balloons? These gases are less dense than the surrounding air, so the balloon floats up. What happens to the volume of the balloon as it rises in the atmosphere? Surrounding air pressure decreases, so the balloon gets bigger. Eventually it pops. Daily Warm-Up Exercises 4

Simulation Turn to page 39 in your lab notebook. Complete this page as you work with the simulation. Daily Warm-Up Exercises 5

Visualization Exercise 6.3 Reading a Line Graph >>>next slide<<< Visualization Exercise 6.3

Image: CD-Rom Exercise 6.3 Module Images: CD-ROM / online Procedure: Image comprehension focus: Reading a line graph Rationale: Authors may sometimes use a line graph as a way of representing certain pieces of information. Therefore, it is important that students understand how to read such graphs. Type of Activity: Teacher Comment Objective: To reinforce student understanding of conventions used in simple line graphs. Module Images: CD-ROM / online Procedure: Explain: “This image is a graph that comes from the CD-ROM (or from online). The graph plots a series of temperature measurements taken by a balloon as it rises from the ground into the sky.” Explain: “This is an example of a kind of data graph which is called a line graph. It is called a line graph because individual data points are connected by small, straight line segments.” Ask: “What is a ‘data point?’” [A data point represents one single observation or measurement.] Ask: “In this graph, what does the vertical or Y axis stand for?” [The label at the top tells us that it shows altitude in kilometers] Ask: “In this graph, what does the horizontal, or X axis stand for?” [The label indicates that it represents temperature in degrees Celsius] <<< Advance the slide to fly-in a circle surrounding the top-most data point>>> Ask: “This dot represents one of the data points from the balloon. The height of this dot tells us that when this measurement was taken, the balloon was about 17 kilometers above the ground. To find the temperature, we read straight down from the data point, and we can see that it was about -77 degrees.” <<< Advance the slide to fly-in a circle surrounding another data point>>> Ask: “Tell me the altitude and temperature for this data point.” [Altitude is about 11 kilometers, temperature is about -56 degrees Celsius.] Ask: “Tell me the altitude and temperature for this data point.” [Altitude is about 3 – 3.5 kilometers, temperature is about -19 degrees Celsius.] Explain: “When the data points have been plotted, then connected with lines, it makes it easy to see the overall pattern. When they are all put together, all of those short like segments look like one big, curvy line – and that big line is showing us what happens to the temperature as you go higher and higher into the atmosphere.” Ask: “What happens to the temperature as you gain altitude?” [it gets colder and colder.] Explain: “There is one other thing you should start doing whenever you see any kind of diagram or graph – you should always ask yourself WHY the artist drew the picture in the exact way that they did. Ask: “For example, the light-blue, criss-cross lines are called grid lines. Why do you think the artist put those in the graph?” [Students may say that it makes it easier for the artist to plot the data points in the first place – but the important idea is that those who make graphs make their decisions in order to make it easier for the READER, and not for the artist. In this case, if necessary, guide them to the idea that the grid lines make it easier for the reader to approximate the altitude and temperature – just as you did in the first part of this exercise.] Ask: “Why do you think that the data points, the boarder, and the grid lines are all blue?” [In this case there is no certain answer, and students may have several different ideas. These may include ‘because the sky is blue, and this is about something rising into the sky’ – or – “blue means cold, and this is about how cold it is as you go up’ – or even – ‘because blue is pleasant to look at.’ The important point right now is to encourage them to consider details of diagrams, and try to figure out why they were drawn that way. This is a sophisticated way to think of visually presented information, and is a valuable habit.] >>>end of exercise<<<

Reading Read Weather Balloons and Upper-Air Soundings on pages 43-44 of your Resources book. Complete the questions on page 44. Daily Warm-Up Exercises 8

Sounding Turn to page 81 in the Resources book. This is radiosonde data from 4 cities. A set of data from a weather balloon is called sounding. Turn to the graph on page 40 of your lab notebook. Each student will plot the data for 1 city. Daily Warm-Up Exercises 9

Sounding Graph Graph altitude vs. air temperature in red. Graph altitude vs. dew point in blue. How are the plots alike? Both air temperature and dew point decrease as the balloon rises. How are the plots different? Some dew-point and air-temperature lines cross and others don't. Daily Warm-Up Exercises 10

Think About Condensation Did condensation occur anywhere along the balloon's upward journey? If the air temperature is the same as the dew point, condensation could occur. What would you expect to see if condensation occurred? clouds Daily Warm-Up Exercises 11

Think About Condensation Which cities most likely had clouds on this day? Chicago and Boston because the air-temperature and dew-point lines are almost the same. Would you expect to see clouds in Phoenix? Not really, because the lines never cross. Daily Warm-Up Exercises 12