# Tools to Study Tornados and Galaxies

Suggested Grade Level(s): 8-12

Estimated class time: 1 hour

# Summary

Students will investigate the Doppler Effect and discover how the same
principle can be used to identify a possible tornado in storms clouds
and investigate the rotation of distant galaxies.

# Objectives

-   Students will show how the Doppler Effect causes electromagnetic
    waves to be shortened or lengthened as an object approaches or
    recedes from the observer.

-   Students will construct a velocity radar "image" that indicates a
    Tornado Vortex Signature.

-   Students will compare their meteorological radar data to
    astronomical visible light data collected from galaxies to see the
    same principal holds true using any wavelengths of the spectrum.

# National Science Standards

-   NS.5-8.1 SCIENCE AS INQUIRY

> As a result of activities in grades 5-8, all students should develop

-   Abilities necessary to do scientific inquiry

-   Understandings about scientific inquiry

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-   NS.9-12.1 SCIENCE AS INQUIRY

> As a result of activities in grades 9-12, all students should develop

-   Abilities necessary to do scientific inquiry

-   Understandings about scientific inquiry

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-   NS.9-12.4 EARTH AND SPACE SCIENCE

> As a result of their activities in grades 9-12, all students should
> develop an understanding of

-   Origin and evolution of the universe

# Knowledge Prerequisite

Students should be familiar with the Electromagnetic Spectrum and the
concept of Doppler Shift. Visit these sites for excellent background:
<http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html> and
<http://imagine.gsfc.nasa.gov/YBA/M31-velocity/Doppler-shift-2.html>

# Teacher Background

Describe some of the background the teacher may need to complete this
activity. Sprinkle these throughout the lesson plan as necessary.

# Materials

For each group of 2 or 4 students:

-   Safety glasses

-   A Slinky toy (plastic is recommended, but either plastic or metal
    will work)

-   Meter stick

-   Velocity (Doppler) RADAR image of Raymond, Illinois for each student
    (included at the end of this lesson plan)

-   Galaxy map of NGC 4254 for each student (included at the end of this
    lesson plan)

-   Colored pencils including Red, Green, Orange, Yellow, and Blue

# Procedure:

### I. Engagement 

Set up the following scenario for your students:

It is mid-May and you are sitting in science class trying to pay
attention as your teacher explains research about motion in deep space.
She says that experiments have revealed information using changes in
visible light, but your mind wanders to thoughts of coming summer
vacation. You notice that the sunny spring sky outside has changed to
dark and ominous when suddenly the principal announces on the PA that a
TVS has been sighted and all students should follow emergency weather
procedures! You remember that TVS stands for Tornado Vortex Signature
and feel a rush of adrenalin. The lesson on space ends abruptly as your
class evacuates to the basement of your school where you crouch against
the walls until the All Clear signal is given and you return reluctantly
to class. When everyone is seated again, the teacher asks how studying
tornados with RADAR could be related to studying light shift from
galaxies? The tornado was a near miss, just a few miles away. How could
that be connected to something in space millions of light years away?

### II. Exploration

Review what you already know about the Electromagnetic Spectrum.
(Answers to questions/choices are shown in **bold** print.) All forms of
radiant energy travel through space in waves. Shorter wavelengths have
(**more**, less) \_\_\_? energy, longer wavelengths have (more,
**less**)\_\_\_\_? energy, but they all travel at the (**same**,
different) \_\_\_\_? speed. (Hint: What is the "speed of light"?
**300,000km/sec.)**

1.  What do we call the shortest waves of the EM spectrum?\_\_\_\_\_
    **gamma rays**. What is an approximate wavelength for those waves?
    \_\_\_\_\_**10^-15^ meters** What do we call the longest waves of
    the spectrum and approximately how long are they?\_\_\_\_\_\_
    **radio waves, 10^4^ meters**

2.  Put on your safety glasses now. We will use the Slinky toy to
    represent these waves of energy. One complete loop of the Slinky
    will represent one wavelength. Lay the meter stick flat on the
    table. Tape one end of the Slinky very securely to the zero end of
    the meter stick and stretch it until you can hold the other end of
    the Slinky at the opposite end of the stick. (Remind students not to
    release the Slinky from the stretched position. Sudden compression
    often leads to a tangled Slinky and painfully pinched fingers!)
    Wavelength is measured from a point on the wave to a corresponding
    point on the next wave. Measure the wavelength at three different
    places along the stick. What is the wavelength? Location
    a.\_\_\_\_\_\_\_\_\_\_\_\_\_\_, location
    b.\_\_\_\_\_\_\_\_\_\_\_\_\_, location c.\_\_\_\_\_\_\_\_

3.  At this time neither end of the Slinky is in motion. Hold the zero
    end (observer) of the Slinky in place, but begin to slowly move the
    opposite end away from the observer. What happens to the
    wavelength?\_\_\_\_\_\_\_ **wavelength gets longer** Now begin
    moving in the opposite direction toward the observer. What is
    happening to the wavelength?\_\_\_\_\_\_\_ **wavelength becomes
    shorter** (Teacher can reinforce the result by holding the dangling
    Slinky in a vertical position and allowing it to gently oscillate up
    and down, with longer wavelengths going down away from your hand and
    shorter wavelengths as it returns toward your hand. Do not allow
    students to do this or tangled toys may result!)

4.  What do we call this change in wavelength as radiant object moves
    toward or away from the observer? \_\_\_\_\_\_\_\_ **Doppler Shift
    (Red or Blue Shift is also correct)**

The same phenomenon occurs regardless of the region of the
Electromagnetic spectrum we examine, and we can use this observation to
tell us a great deal about the motion of objects very nearby or very,
very far away.

5.  The following USA Today article discusses how RADAR wave reflections
    from rain drops can be used to find out if parts of a storm cloud
    are moving toward or away from the RADAR station:
    <http://www.usatoday.com/weather/wdoppler.htm>

6.  Use the colored pencils to fill in the pixels of the velocity RADAR
    image. RADAR (actually microwaves) are not in the visible light
    portion of the spectrum, but we will use Green and Red pixels to
    represent waves reflecting from parts of clouds coming toward or
    going away from the RADAR station. If they were visible, which would
    be longer waves, blue or red?\_\_\_\_\_\_\_**Red is a longer
    wavelength than Green** Therefore we will use (red, **green**) to
    represent wave reflections coming toward the station and (**red**,
    green) to represent wave reflections going away from the station. If
    the RADAR image shows an area where Green and Red pixels are side by
    side, coming toward and going away, at a speed of at least 45 knots
    in both directions, we know that this could indicate the rotation
    which accompanies a beginning tornado.

7.  A **TVS**, Tornado Vortex Signature, alert is sent to everyone in
    the general area so that they can take precautions. Which area/areas
    of your image show something that could be a TVS? **3 TVS signatures
    are indicated**

> Visit <http://www.hprcc.unl.edu/nebraska/Greensburg3_small.gif> to see
> another TVS image of a tornado that occurred in Greensburg, Nebraska.
> <http://www.hprcc.unl.edu/nebraska/Greensburg3_small.gif>
>
> The Dopplar velocity RADAR image shows several towns in Montgomery
> County Illinois on the night of June 2, 1999. The towns of Waggoner,
> Harvel, and Raymond are marked on the map. Three tornados touched down
> near the three towns at almost the same time! Pixels on the map are
> shown larger than actual.

8.  Now use your colored pencils to complete the galaxy map of NGC 4254.
    This map shows the shift in wavelengths of visible light coming from
    the galaxy. Red shift indicates wavelengths getting longer or
    shorter? \_\_\_\_\_ **longer**. Blue shift would indicate
    wavelengths getting \_\_\_\_\_\_? **shorter** What does that suggest
    about the motion of the galaxy? **It seems to be rotating around a
    central point.** Visit the following web page to see maps of NGC
    4254 and some other
    galaxies:![](media/image1.pct){width="5.0881944444444445in"
    height="2.175in"}

> [[http://www.obspm.fr/actual/nouvelle/jan06/virgo.en.shtml]{.underline}](http://www.obspm.fr/actual/nouvelle/jan06/virgo.en.shtml)

For a photograph of the galaxy visit the following webpage:

> [[http://www.astr.ua.edu/gifimages/ngc4254.html]{.underline}](http://www.astr.ua.edu/gifimages/ngc4254.html)

A couple notes about the two images:

-   The orientation for the two images is somewhat different. The RADAR
    map is oriented so that we are looking down at the surface of the
    Earth, as shown in picture (a) in the figure box above. The galaxy
    velocity map, however, is shown from the edge of the galaxy, similar
    to picture (b) in the figure box above.

-   The velocity scales for the two images are also different -- the
    RADAR image shows three velocity increments **away** from the RADAR
    station, with only one **toward** the station. The galaxy map shows
    two velocity increments away from the Earth and one toward. This is
    why the colors on the maps are slightly different. However, the
    important point is that one object showing adjacent velocity
    measurements that are toward and away from the viewer indicate
    rotation.

### III. Explanation

Meteorologists use Doppler Shift to locate potential tornados. Other
scientists, using the same principal of a shift in wavelength from
objects moving toward or away from the observer, can also use other
regions of the Electromagnetic spectrum to observe possible motion.

How could an astronomer use the visible light waves coming from the sun
to find out if the sun rotates on its axis? (Hint: refer to the image of
the TVS and galaxy map above) **Blue shifted wavelengths on one limb of
the sun coming toward us and red shifted wavelengths on the opposite
limb rotating away from us**

If all of the visible light wavelengths coming from a very distant star
appeared similar to our own nearby sun EXCEPT that all of the
wavelengths seemed just a little longer than they "should" be, what
might that suggest about the motion of the distant star? **It is moving
away from the observer**

When you look at the galaxy map of NGC4254 and the other galaxies shown
at the website, what do the colors tell you about the motion of the
galaxies? **All of the galaxies indicate they are rotating**

### IV. Evaluation 

Write a short paragraph to respond to your teacher's question about how
studying nearby tornadoes with RADAR is related to studying distant
galaxies in space.

### Velocity RADAR image

<table>
<colgroup>
<col style="width: 8%" />
<col style="width: 10%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 9%" />
<col style="width: 8%" />
</colgroup>
<tbody>
<tr class="odd">
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
</tr>
<tr class="even">
<td>0</td>
<td>0</td>
<td>0</td>
<td>2</td>
<td>4</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
</tr>
<tr class="odd">
<td>3</td>
<td>3</td>
<td>2</td>
<td>2</td>
<td>4</td>
<td>2</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
</tr>
<tr class="even">
<td>3</td>
<td>3</td>
<td>4</td>
<td>4</td>
<td>3</td>
<td>2</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
</tr>
<tr class="odd">
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>0</td>
<td>0</td>
</tr>
<tr class="even">
<td>3</td>
<td>Waggoner</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>0</td>
<td>0</td>
</tr>
<tr class="odd">
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>4</td>
<td>2</td>
<td>1</td>
<td>2</td>
<td>3</td>
<td>3</td>
<td>0</td>
</tr>
<tr class="even">
<td>3</td>
<td>1</td>
<td>2</td>
<td>2</td>
<td>2</td>
<td>Harvel</td>
<td>2</td>
<td>4</td>
<td>3</td>
<td>3</td>
<td>0</td>
</tr>
<tr class="odd">
<td>3</td>
<td>2</td>
<td>2</td>
<td>4</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
</tr>
<tr class="even">
<td>3</td>
<td>3</td>
<td>3</td>
<td>4</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
</tr>
<tr class="odd">
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>4</td>
<td>4</td>
<td>3</td>
<td>3</td>
<td>2</td>
<td>1</td>
</tr>
<tr class="even">
<td>1</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>4</td>
<td>3</td>
<td>3</td>
<td>3</td>
<td>4</td>
<td>Raymond</td>
<td>2</td>
</tr>
<tr class="odd">
<td>1</td>
<td>4</td>
<td>4</td>
<td>4</td>
<td>4</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>4</td>
</tr>
<tr class="even">
<td>1</td>
<td>4</td>
<td>0</td>
<td>4</td>
<td>3</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
</tr>
<tr class="odd">
<td colspan="2"><p>Doppler</p>
<p>RADAR</p></td>
<td colspan="2">1in = 1 mile</td>
<td> </td>
<td> </td>
<td colspan="3"><p>Montgomery County</p>
<p>Illinois</p></td>
<td> </td>
<td> </td>
</tr>
<tr class="even">
<td colspan="2"><p>0 blank</p>
<p>(no cloud motion)</p>
<p> </p></td>
<td colspan="2"><p>1 red</p>
<p>(30 knots away)</p>
<p> </p></td>
<td colspan="2"><p>2 yellow</p>
<p>(20 knots away)</p>
<p> </p></td>
<td colspan="2"><p>3 orange</p>
<p>(5 knots away)</p>
<p> </p></td>
<td colspan="2"><p>4 blue</p>
<p>(20 knots toward)</p>
<p> </p></td>
<td> </td>
</tr>
</tbody>
</table>

###  Velocity map of Galaxy NGC 4254

<table>
<colgroup>
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 9%" />
</colgroup>
<tbody>
<tr class="odd">
<td>0</td>
<td>0</td>
<td>1</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
</tr>
<tr class="even">
<td>0</td>
<td>1</td>
<td>1</td>
<td>1</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
</tr>
<tr class="odd">
<td>1</td>
<td>1</td>
<td>1</td>
<td>1</td>
<td>1</td>
<td>2</td>
<td>3</td>
<td>0</td>
<td>0</td>
<td>4</td>
<td>0</td>
</tr>
<tr class="even">
<td>0</td>
<td>1</td>
<td>1</td>
<td>1</td>
<td>1</td>
<td>2</td>
<td>3</td>
<td>3</td>
<td>0</td>
<td>4</td>
<td>4</td>
</tr>
<tr class="odd">
<td>1</td>
<td>1</td>
<td>1</td>
<td>1</td>
<td>1</td>
<td>2</td>
<td>3</td>
<td>3</td>
<td>4</td>
<td>4</td>
<td>4</td>
</tr>
<tr class="even">
<td>0</td>
<td>1</td>
<td>1</td>
<td>1</td>
<td>2</td>
<td>2</td>
<td>3</td>
<td>3</td>
<td>4</td>
<td>4</td>
<td>4</td>
</tr>
<tr class="odd">
<td>1</td>
<td>1</td>
<td>1</td>
<td>1</td>
<td>2</td>
<td>3</td>
<td>3</td>
<td>4</td>
<td>4</td>
<td>4</td>
<td>4</td>
</tr>
<tr class="even">
<td>1</td>
<td>1</td>
<td>1</td>
<td>2</td>
<td>2</td>
<td>3</td>
<td>4</td>
<td>4</td>
<td>4</td>
<td>4</td>
<td>4</td>
</tr>
<tr class="odd">
<td>1</td>
<td>1</td>
<td>1</td>
<td>2</td>
<td>2</td>
<td>3</td>
<td>4</td>
<td>4</td>
<td>4</td>
<td>4</td>
<td>4</td>
</tr>
<tr class="even">
<td>0</td>
<td>0</td>
<td>1</td>
<td>2</td>
<td>0</td>
<td>3</td>
<td>3</td>
<td>4</td>
<td>4</td>
<td>4</td>
<td>0</td>
</tr>
<tr class="odd">
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>3</td>
<td>4</td>
<td>4</td>
<td>4</td>
<td>4</td>
<td>4</td>
</tr>
<tr class="even">
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>4</td>
<td>4</td>
<td>0</td>
<td>4</td>
<td>4</td>
<td>0</td>
</tr>
<tr class="odd">
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>4</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>4</td>
<td>0</td>
</tr>
<tr class="even">
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
</tr>
<tr class="odd">
<td></td>
<td></td>
<td> </td>
<td colspan="8"><p> </p>
<p>90000 light-years across, each pixel is 7500 light-years
across</p></td>
</tr>
<tr class="even">
<td colspan="2"><p>0 blank</p>
<p>(no stars from the galaxy)</p>
<p> </p></td>
<td colspan="2"><p>1 red</p>
<p>(approx. 100 km/s away)</p>
<p> </p></td>
<td colspan="2"><p>2 orange</p>
<p>(approx. 50 km/s away)</p>
<p> </p></td>
<td colspan="2"><p>3 green</p>
<p>(approx. 50 km/s toward)</p>
<p> </p></td>
<td colspan="2"><p>4 blue</p>
<p>(approx. 100 km/s toward)</p>
<p> </p></td>
<td> </td>
</tr>
</tbody>
</table>