Weather Balloon Launch Movie Activity

Weather Balloon Launch Movie Activity

Grade Level:K - 8

Subject: Earth and Space Science

Prep Time:< 10 minutes

Duration: 30 minutes

Objective: / To challenge students’ perspectives of the sky and better understand temperature and pressure variations in the Earth’s atmosphere.

Description:

This activity involves watching a video of a weather balloon launch executed by the PHYS240 class at The Catholic University of America in Spring 2013. Students will make predictions about the balloon’s flight before watching the video and then analyze the data that was retrieved from the payload.

Materials:

Student Sheets
Balloon launch movie:

Related Links:

Additional Video Links:

National Science Education Standards:

Content Standard / Levels K - 4 / Levels 5 - 8
Earth and Space Science /

Changes in earth and sky
Objects in the sky

Earth in the solar system

Science as Inquiry /

Abilities necessary to do scientific inquiry
Understanding about scientific inquiry

Abilities necessary to do scientific inquiry
Understanding about scientific inquiry

Science and Technology /

Abilities to distinguish between natural objects and objects made by humans
Abilities of technological design
Understanding about science and technology

Abilities of technological design
Understanding about science and technology

Background:

On April 21, 2013, Catholic University of America students enrolled in PHYS 240, a course designed for Education majors and entitled “The Earth-Sun Connection,” launched a small research balloon from The Outdoor School at Fairview, 11 miles west of Hagerstown, MD.

The balloon was attached to a parachute and a payload, which contained a GPS unit, a digital video camera with a wide-angle lens, a simple analog refrigerator thermometer, and two biological specimens. The camera was set up to have a horizontal view from the payload, with the thermometer in the right hand corner of the camera’s field-of-view to see the temperature change throughout the entire flight.

The purpose of this flight was to show students that science is a fun and active process. Preparing for this balloon launch allowed students to see the time, planning, and details that go into a scientific experiment. Using software available on the Web, coupled with the weight of the payload and amount of helium in the balloon, students had to predict the flight path of the balloon and payload. This was needed in order to retrieve the payload and information recorded by the camera.

Once the balloon was launched, and the data collected, it allowed the students to learn about the sky and changes in the Earth’s atmosphere. The balloon reached an altitude of 73,000 ft before the balloon burst, followed by the payload parachuting back to Earth. The total flight time was an hour and 31 minutes. The payload, which the students found using the GPS on the payload, landed 10 miles NW of York, PA. The payload traveled roughly 65 miles and landed within one mile of that predicted. During the flight, the payload recorded temperatures as low as -70 ℉ and encountered severe turbulence about 60,000 ft. Further, more sophisticated flights are planned where additional data will be obtained.

A shortened video highlighting the main events of the launch and flight was created from movies taken from an iPhone at the launch and payload retrieval sites as well as from the payload camera. It was shortened from approximately two hours to twelve minutes and 30 seconds. The sound was amplified 300% so that viewers can hear the wind as well as see the earth below. The part of the video recording the balloon burst (~8:02 on the video) has been slowed down so the viewer can see the pieces of the balloon float by the camera after the burst.

Procedure:

Give the students some background on the video then ask them to illustrate and write down their predictionsof what will happen during the balloon flight in the Procedure section of the student activity sheet.
Let the students share their some of their predictions with the class.
Play the video. Encourage the students to take some notes during the video and watch out for times when the camera is moving a lot and when the shape of the earth becomes apparent.
Point out when the balloon is moving through the clouds (~5:20). Pause the video here and/or emphasize what the thermometer reads.
After the video finishes playing. Ask the students what happened in the video and how well it matched their predictions. Then ask them to complete the Questions portion of the student activity sheet.

Answers:

The sky starts off light blue then turns into a darker blue and eventually black once the balloon is out in space and reaches its maximum height.
Give the students the hint that the thermometer reads -20℉ when the balloon is in the clouds and ask them to use Figure 3. The balloon is moving through the clouds about halfway up to its maximum height. To someone walking on the ground, clouds may look like they are far away but compared to the height of Earth’s atmosphere clouds are at a very low altitude (See Figure 2). Think about when an airplane takes flight. It does not take very long to reach the clouds.Also, airplanes fly slightly higher than cloud cover so it’s safe to say that the balloon in this video travelled about twice as high as an airplane goes.
It sounds like a jet when it is rising. We also hear the wind whistling. When the balloon starts falling the sound is quieter.
At the top of the flight, just before the balloon burst.
At the top of the flight.
They used the GPS to track the location of the balloon when it landed. A tracking device was attached to the payload of the balloon while satellites in space transferred information about the location of the balloon to the students on the ground. They also used the GPS to see where the balloon was throughout its flight so that they could predict ahead of time where it was headed.
See Figure 1. Note that the camera attached to the balloon is oriented upside down (the top of the camera is facing the surface of the Earth.
The Earth has a curved shape. The actual shape of the Earth is a sphere; it is not flat, as it may seem to someone walking on the ground. There is a bright blue layer at the edge of the Earth’s surface. This is the lower part of the atmosphere. Due to clouds, from this image we cannot see enough of the Earth to make out any prominent features but we can see some dark areas that are land.
The camera is pointing towards the edge of Earth, so we can see part of Earth and part of space.
This balloon launch took place in the daytime, which means that the Sun was casting light on the side of the Earth that the balloon was launched from. So the balloon is somewhere between the Sun and the Earth. Notice the shadow on the thermometer in Figure 1. Draw a line that extends the shadow to the bottom edge of the picture. This is where the sunlight is coming from.
The balloon exploded before it could keep travelling outwards. We see white fragments of the balloon after it has just burst at the top of its flight.
As the balloon travels upward, the air pressure drops (see Fig. 2) and the gas in the balloon is expanding. At the top of the flight, the rubber balloon material can no longer handle the stretching caused by the expanding gas and so it pops. The balloon bursts at the point that there is no longer enough air pressure to keep the balloon together.
Figure 2 is a known model of the temperature profile of Earth’s atmosphere. Students only need to be concerned with the altitude in km on the left vertical axis and the temperature in Fahrenheit on the horizontal axis. Figure 3 is the data collected from the payload of the balloon flight. The data was output in Fahrenheit, the standard unit of temperature in the U.S.
Students may not have expected the temperature to drop then begin to rise again before the balloon pops. They might have predicted that the temperature keeps dropping the higher you go in the atmosphere.
As we can see from this model, the temperature in the Earth’s atmosphere actually rises and falls several times.
The temperature reads about -45℉ when the balloon pops. From Fig 3, the balloon passes through -45℉ three times—first when it is travelling upwards, then when the balloon pops, and last when it is falling. In Figure 2, locate this temperature on the horizontal axis then move vertically to locate the second altitude that we see this temperature in the model. The answer is ~25 km. The balloon went past the troposphere and into the stratosphere.
~ -70℉. Between 10-20 km. The stratosphere.
We know that the balloon was rising (increasing height) until the balloon burst at 70 min. Then the balloon was falling (decreasing height).
The data matches the model up until the balloon pops (after which it is just the reverse temperature profile). Notice that the data has the same shape as the model if you rotate Figure 3 by 90° counterclockwise then 180° from left to right.

Teacher Sheet

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Weather Balloon Launch Movie Activity

Materials:

Student Sheets
Balloon launch movie:

Background:

On April 21, 2013, Catholic University of America (CUA) students enrolled in PHYS 240, a course designed for Education majors and entitled “The Earth-Sun Connection,” launched a small research balloon from The Outdoor School at Fairview, 11 miles west of Hagerstown, MD.

Vocabulary:

Temperature: A measure of how hot or cold something is. In the metric system, temperature is measured in degrees Celsius (℃). For this activity, the device on the balloon payload measures temperature in degrees Fahrenheit (℉), the official temperature scale for the U.S.

Pressure: A measure of force exerted over some area. For example, a fish in water experiences water pressure coming from all directions. Pressure is measured in Pascals (Pa) in the metric system. Meteorologists use millibars (mb).

Altitude: The height of an object as measured from the ground.

Atmosphere: A layer of gases that surround the Earth and are bound by gravity. From lowest to highest, the layers of the atmosphere are called the troposphere, stratosphere, mesosphere, and thermosphere. The thermosphere extends into outer space.

Global Positioning System (GPS): A navigation system that consists of one or more satellites in space that tracks the position and time of an object. This information is relayed live via some device to a user on the ground.

Payload: The carrying capacity of the weather balloon. The payload may consist of scientific instruments, passengers, cargo, housing devices, or any other object attached to the balloon.

Procedure:

You will be watching a 10 minute clip of a weather balloon being launched and retrieved by students in the PHYS240 course at CUA in 2013. Before watching the video make predictions of what will happen to the balloon through the course of its flight. Imagine being a tiny ant sitting on the balloon as it rises. What would you see? Write down your predictions below and sketch a picture.

When you are finished, watch the video of the balloon launch with your class and answer the questions on the following pages. Write down your answers on a separate piece of paper.

Questions:

How does the color of the sky change in the background while the balloon goes up?
When the balloon is rising, is it always moving through clouds? If not, then when? Near the bottom, middle, or top of the flight?

Could you hear any changes in sound during the balloon journey? Describe them.
Describe how the balloon swings. When does it swing the most?
When could you really see the curved shape of the Earth in the video?

How did they determine where the balloon landed?
Use Figure 1 below to answer questions 6a-6e.
What does the earth look like from space? What shape is it? What colors do you see? Can you see mountains, valleys, bodies of water, etc.? If not, explain why.
Which way is the camera pointing?
Can you tell which direction sunlight is coming from? Next to Figure 1, sketch the Sun on the side you think it is located at. (left, right, top, or bottom)
Why didn’t the balloon keep flying out into space?What has happened to the balloon in this picture?
What do you think caused this? Hint: There is less air pressure higher in the atmosphere.

Use Figures 2-3 to answer questions 7a-7g.
Look at the data collected from the balloon launch. How does the temperature change over time during the flight? Is it what you would have expected?
Now look at the temperature variation in Figure 2. Is this what you would have expected?
The balloon is at its highest point when it pops. Use Figure 3 to find out what temperature the payload thermometer read when the balloon popped. Then use Figure 2 to find the height of the balloon (in kilometers) at that moment.
What is the lowest temperature that the balloon experienced? At what height did this occur? What is this layer of the atmosphere called?
Figure 3 plots time, but not altitude, on the horizontal axis. Can you still guess how the height was changing over time? During what time was the balloon rising? Falling?
Is the temperature change in Figure 3 from the time of launch to the time of the balloon burst consistent with Figure 2, which is a scientifically verified model?

Additional Video Links:

Student Sheets

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