Where in the World is our Mystery Class?

Cheryl LykowskiLourdes College-

EDU 613March, 2006

Mystery Class Background

The Mystery Class investigation is an 11-week hunt in which students try to find

the location of 10 secret "Mystery Classes" hiding around the globe. The

changing amount of sunlight at each site is the central clue, followed by longitude clues and verbal clues. Students take an

exciting journey from knowing only sunrise and sunset times, to discovering

exact locations of the 10 Mystery Classes.

Mystery Class Objective

In a global game of hide and seek, you will track changing

daylight at ten secret sites around the world. This

investigation demonstrates that, as spring sweeps across the Northern Hemisphere, day length changes everywhere on earth. You will see that these dramatic seasonal changes in

sunlight affect the entire web of life.

Table of

Contents

Mystery Class supports:

• Scientific observations• Data collection• Student-directed inquiry• Scientific procedures

Table of

Contents

Mystery Class Table of Contents

Sunlight and the Seasons

Tracking Photoperiod

Calculating Photoperiod

Latitude & Longitude

Longitude Clues

Interdisciplinary Clues

Sunlight and the Seasons

Exploring the Sun's Role in the Living Systems

You have learned that sunlight makes plants grow, some animals eat plants, and predators eat other animals. However, did you know that these food chains and webs change with the seasons? For example, during spring in the Northern Hemisphere, lengthening and strengthening sunlight and rising temperatures boost plant photosynthesis, which increases the amount of food they produce.

Table of

Contents

Sunlight and the SeasonsExploring the Sun's Role in the Living Systems

Make a list of five changes you think the sun will bring about as

winter wraps up and spring springs forth in our community. Think of both physical changes

(e.g., temperatures) and biological changes (e.g., plant growth). What kinds of impact does each physical

change (e.g., ice melting, more daylight hours, temperatures

warming) have on living things — particularly on their ability to

make or get food?

Table of

Contents

Sunlight and the SeasonsExploring the Sun's Role in the Living Systems

Table of

Contents

Sunlight and the SeasonsExploring the Sun's Role in the Living Systems

Click on the movie below to view a short video clip on sunlight and the seasons.

Table of

Contents

Tracking Photoperiod

Beginning next Monday, check your local newspaper and retrieve your town's sunrise and sunset times for that date. Then be sure to record these times for your hometown on a Mystery Class Datasheet. Just four days later, on Friday, Journey North will post the first sunrise/sunset data for ten secret Mystery Classes. Be sure to record this Sunrise/Sunset data on the Mystery Class Datasheets too.In the weeks that follow, continue to record your own local sunrise/sunset data every Monday, and the secret Mystery Classes' sunrise/sunset data every Friday, and be sure to graph photoperiod changes too.

Table of

Contents

Tracking Photoperiod

Mystery Class Data Sheet

DATE Sunrise Sunset Photoperiod

Jan. 30

Feb. 6

Feb. 13

Feb. 20

You will be given a data sheet like the one above to keep track of your Mystery Class’ photoperiod every week for the next eleven

weeks.

Table of

Contents

Tracking Photoperiod

Once a week for eleven weeks, you will receive sunrise and sunset times for all ten secret mystery sites. After figuring

the photoperiod for your Mystery Class, you will be expected to graph your results on the large wall graph.

Table of

Contents

Tracking Photoperiod

Click on the movie below to view a short video clip on tracking

and graphing weekly photoperiod clues.

Table of

Contents

Calculating PhotoperiodSunrise and sunset occur because the Earth is spinning on its axis. During

Mystery Class, you will receive sunrise and sunset times from around the world.

A global view of Earth's 24-hour cycle can be hard to visualize. Below is a view

of the 24-hour clock or military time.

Table of

Contents

Calculating Photoperiod

• If the sunrise is at 6:14 a.m. and the sunset is at 9: 36 p.m., you would divide the photoperiod into two parts: the amount of time before noon and the amount of time after noon.

• You might work it through like this: from sunrise (6:14) to 6:30 is 16 minutes, from 6:30 to noon is 5 hours and 30 minutes, so from sunrise to noon is 5 hours and 46 minutes.

• From noon to sunset is 9 hours and 36 minutes so the total would be 14 hours and 82 minutes.

. Since you know that there are only 60 minutes in

an hour, it becomes 15 hours and 22 minutes.

Here are two ways in which you can calculate the photoperiod of a location from sunrise and sunset

data.

1st way:

Table of

Contents

Calculating Photoperiod

Convert sunrise and sunset numbers to a 24-hour clock and subtract sunrise from sunset.

2nd way:

sunset 9:36

sunrise 6:14

photoperiod

convert to 24 hour clock

sunset 21:36

sunrise -6:14

15:22

photoperiod 15 hours and 22 minutes

Table of

Contents

Calculating Photoperiod

Now you try it!

Sunrise 6:24 am Sunset 7:44 pm

Step 1: Determine the sunset on the 24-hour clock.

Sunset 19:44 pm

Step 2: Subtract the sunrise from the sunset.

19:44

-6:24Table

of Contents

Calculating Photoperiod

19:44 -6:2413:2013 hours/20 minutes

How did you do?

Table of

Contents

Latitude & Longitude

Did you know that every location on earth has a global address that everyone can understand, no matter what language they might speak? Or how remote the place might be?

A global address is given as two numbers called coordinates. The two numbers are a location's latitude number and its longitude number.

Table of

Contents

Latitude & Longitude

Think about having imaginary horizontal "hula hoops" around the earth,

with the biggest hoop around the equator, and

then progressively smaller ones stacked above and

below it to reach the North and South Poles

Latitude

Table of

Contents

Latitude & Longitude

Visualize hula hoops cut in half, vertically positioned with one

end at the North Pole and the other at the

South Pole.

Longitude

Table of

Contents

Longitude CluesThese images of Earth taken from space show the

location of sun's light changes from one hour to the next as Earth rotates on its axis. The time is shown as "UT,"

or Universal Time; this is also known as "GMT," or

Greenwich Mean Time. Images courtesy of Living Earth (Click for larger image.)

                               

                                 

                               

                                 

                               

                                 

         

                       03:55

GMT04:55 GMT 05:55

GMT06:55 GMTWhat do you notice?

What does it "tell" you? How are sunrise and longitude related in the photos above? What season is it in the northern hemisphere? Explain how you know. Find out what scientists say.

Table of

Contents

Longitude Clues

On the spring equinox, sunrise data given in Greenwich Mean Time reveals the approximate longitude of each secret site. With longitude

uncovered, the search for secret sites is narrowing.

Click on the movie clip below to view a short video on longitude.

Table of

Contents

Longitude Clues

There are certain clues that can help you estimate Longitude when used in connection with the

SPRING EQUINOX. These are called The Longitude Clues.

Only on the Equinox (spring or fall) do these clues work. As your graph will show, on the Equinox everyone on earth has about the same amount of daylight. At all other times of year, either the Northern Hemisphere or Southern Hemisphere has more daylight due to the tilt of the Earth's axis. But on the Equinox, neither of the poles of the Earth is tilted toward or away from the sun. Because of this fact, using the Longitude Clues, you will be able to estimate approximate LONGITUDE by knowing the time of sunrise at the Mystery Class on the Equinox when you are given that sunrise time in Greenwich Mean Time (GMT). Table

of Contents

Longitude CluesMystery Class GMT Worksheet

Estimating Approximate Longitude using GMT Sunrise Timeson the Vernal Equinox

Step # 1 Fill in the GMT sunrise time and date for the Mystery Class. This is the time it is in Greenwich, England when the sun rises at the Mystery Location. Put in Box A.

BOX A_______time______date

Step # 2 Fill in the time that the sun rises in Greenwich, England on March 20, the spring Equinox. This year that sunrise time is 06:03 A.M.Put in Box B.

BOX B

06:03 A.M. (3/20)

Step # 3 Figure out how many hours and minutes there are between the time in Box A and the time in Box B. Put answer in Box C. This is the difference in time between sunrise at Greenwich and sunrise at the Mystery Location. (CAUTION!!! This may not be a simple subtraction or addition equation. Remember that hours and minutes are not in decimal form. Be sure to think

about your answer!) Put in Box C.

BOX C

_______hours______minutes

Table of

Contents

Longitude CluesMystery Class GMT Worksheet Estimating Approximate Longitude

using GMT Sunrise Times on the Vernal Equinox (con’t.)

Step # 4 For the next step you'll need to convert hours to minutes. Multiply each hour in Box C by 60, add the remaining minutes from Box C. Put the answer in Box D.

BOX D

________minutes

Step # 5 Almost done! You now know how many minutes the earth spins between the time the sun rises at the Mystery Class location and the time it rises at Greenwich. Since the earth spins 1 degree longitude every 4 minutes, you must next divide by 4 to get the number of approximate longitude degrees away from Greenwich. Divide the number of minutes given in Box D by 4. Put the answer in Box E.

BOX E

________degree

Table of

Contents

Longitude CluesMystery Class GMT Worksheet Estimating Approximate Longitude using GMT

Sunrise Times on the Vernal Equinox (con’t.)

Step # 6 Eastern or Western Hemisphere?To determine the site's longitude you need to know if it is in the Eastern or Western Hemisphere (i.e East or West of Greenwich, which is 0 degrees).

• If the sunrise time in Box A is later than the sunrise time in Box B, the Mystery Class is west of Greenwich (Western Hemisphere).

• If the sunrise time in Box A is earlier than the sunrise time in Box B, the Mystery Class is east of Greenwich (Eastern Hemisphere).

BOX F

East or West?

Table of

Contents

Interdisciplinary Clues After the spring equinox,

weekly informational clues about the history, geography, culture and other aspects of a location are provided, leading

students progressively closer to unlocking the secret locations.

Click on the picture below to watch a short video clip on

using interdisciplinary clues.

Table of

Contents

Mystery Class ResourcesFollowing is a list of resources to aid you in your journey of finding your Mystery

Class.

Sunrise/Sunset Tables:Locations Worldwide Locations in U.S.Only

Photoperiod(Journey North Mystery

Class)

Check out the following books in our class library.

LONGITUDE, by Dava Sobel THE LONGITUDE PRIZE, by Joan Dash ON THE SAME DAY IN MARCH, by Marilyn Singer

You can also use atlases, maps, encyclopedias, and the internet.

Table of

Contents