STEM Station

ROHN

welcome to

ROHN, AK

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Hidden between the Tatina River and Egypt Mountain, in the sub-alpine spruce forest, sits Rohn checkpoint. This is an area with no humans inhabitants. Instead, it’s rich with wildlife. It’s a wild place, with a cabin, no running water, and subtle remnants of Alaskan history. Though this valley is often a place of solitude, for a few days a year this little remote cabin becomes the epicenter of a small community.

In the early 1900s, the original Iditarod mail route came through this valley. There was a cabin then, too, though the Tatina eventually washed it away. For the ease of the mail carriers, shelter cabins and roadhouses were built about twenty miles apart, because people figured dogs could travel that far between stops. Eventually, a trapper built another cabin in the same stand of trees. Today, all that remains from that era is a crumbled trapper cache and handmade dog chains still attached to the platforms from the original dog houses. Right now, the latter is buried in snow.

Because there is no community here, several people put in many volunteer hours both on off-season to keep the checkpoint Iditarod-ready. As the race approaches, the pilots fly in straw and drop bags to a short, narrow airstrip. The trail-breakers bring down tents from Rainy Pass. Volunteers haul supplies from the runway, buck wood, clear downed brush from the dog yard, do trail maintenance, and set up tents.

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Ruby serves as the Cyber Sled Race checkpoint: STEM Station. Below you will find an abundance of STEM activities.

The content below is for participants of all ages, unless otherwise noted. Utilize your connected worksheets and tracking tools to find the specific information for your rank.

EXPLORE MORE ABOUT WINTER STEM ACTIVITIES

Navigation - the art of finding your way - is important for every Scout to learn.

Since ancient times, rough maps of the Earth and simple compasses have guided explorers, warriors, and pioneers like Lewis and Clark, Marco Polo, Christopher Columbus, and Amelia Earhart. Often, their skills with map and compass were all that kept these men and women from disaster. What has been a vital skill for humans for thousands of years is now a sport—orienteering. In 1919, a Swedish Scout leader, Major Ernst Killander, decided that compasses and maps could be used for fun as well as survival and navigation. Sport orienteering was born on that day, as 155 contestants fanned out around Stockholm with compasses and maps.

HOW SALT AFFECTS ICE

When added to ice, salt first dissolves in the film of liquid water that is always present on the surface, thereby

lowering its freezing point below the ices temperature. Ice in contact with salty water therefore melts, creating

more liquid water, which dissolves more salt, thereby causing more ice to melt, and so on. The higher the concentration of dissolved salt, the lower its overall freezing point. There is a limit, however, to the amount of salt that can be dissolved in water. Water containing a maximum amount of dissolved salt has a freezing point of about zero degrees Fahrenheit. Therefore, the application of salt will not melt the ice on a sidewalk if the temperature is below zero degrees F.

To understand why water containing dissolved salt has a lower freezing point than pure water, consider that when ice and water are in contact there is a dynamic exchange at the interface of the two phase states. Because of thermal vibrations in the ice, a large number of molecules per second become detached from its surface and enter into the water. During the same period of time, a large number of water molecules attach themselves to the surface of the ice and become part of the solid phase. At higher temperatures, the former rate is faster than the latter and the ice melts. At lower temperatures the reverse is true. At the freezing point the two rates are equal. If salt is dissolved in the water, the rate of detachment of the ice molecules is unaffected but the rate at which water molecules attach to the ice surface is decreased, mainly because the concentration of water molecules in the liquid (molecules per cubic centimeter) is lower. Hence, the melting point is lower.

Experiment with salt and ice to see how salt effects ice.

MATERIALS NEEDED

Clean aluminum cans
Thermometer (digital works best)
Ice cubes
Table salt
Coarse rock salt
Measuring spoons

PROCEDURE

Set up 5 tin cans (more if you want to test more variables, types of salt, quantities, etc.)
In each can add the same amount of ice.
Set one can as your control. This one will have no salt added.
In the next two cans add table salt. Can #1 add 1 teaspoon. Can #2 add 2 tablespoons.
In the final two cans add coarse rock salt. Can #1 add 1 teaspoon. Can #2 add 2 tablespoons.
You can gently shake the cans to spread the salt around if you wish. Make sure you set the cans far enough apart from each other that they don’t affect the results of adjacent cans.
Now using your thermometer start taking readings. At the beginning your readings will be similar from each can, but over approximately 20 minutes you will start noticing some big changes!
After 20 minutes, write down the temperatures of each can!

HOW IT WORKS: Salt lowers the freezing point of the ice. This causes it to pull heat from the air and tin can in order to melt the ice, significantly dropping the temperature on the surface of the tin can and in the air. This gives us our low temperature readings. If you live in a moist climate, moisture from the air will freeze as it comes in contact with the cold surface of the can which can lead to the creation of frost.

MELTING MAGIC

NOTE: To do this experiment, you will need snow. If you don't have snow where you live, that's okay! You can use shaved ice or go to the next activity.

MATERIALS NEEDED

3 empty clear jars or cups
Snow
Water
Ice

PROCEDURE

Fill the first jar with water and put on the lid. This is your control.
Fill the next jar we filled with ice cubes. Use cubes, not shaved ice. You want there to be lots of air around the ice cubes. Secure the lid.
Finally, fill the last jar with snow or shaved ice! Fill the jar as full as possible!
Now set the jars in a safe place to see what happens as they melt.
Predict which jar will have more water in it after both melt - the ice or the snow.

HOW IT WORKS: So how did our ice cubes that left so much air in the jar result in more water than our snow? It has to do with the structure of our water molecules. Ice is the solid form of water and the water molecules are stacked together tightly. Snow on the other hand is like ice, but it’s actually precipitation that freezes into a crystallized form. The molecules bond together into the beautiful crystal patterns we associate with snowflakes. There is a lot of air around each crystal snowflake.

snow crystals

NOTE: To do this experiment, you will need snow. If you don't have snow where you live, that's okay! You can use shaved ice or go to the next activity.

MATERIALS NEEDED

Small tree branch (pine trees work perfectly!), or pipecleaners shaped in whatever design you want
Borax Powder
Water
Bowl, Measuring Cup, and Spoon
Mason Jar or Tall Glass {not plastic}

PROCEDURE

Make the Crystal Growing Solution:
- Boil 1 cup of water for every 3 tablespoons of borax powder. Measure borax powder into a boil. Once the water is boiled, turn the heat off and measure the water into the bowl with the borax powder. Stir to mix well. A good amount of solution to make is 3 cups of water + 9 tablespoons of borax.
- The powder will not dissolve. You are making a suspension solution meaning the particles of the powder are suspended in the water due to the heat. As the mixture cools, the particles settle onto the item that is placed in the mixture.
Suspend your tree branch or pipecleaner design in the crystal growing solution. Use clothespins to prop up the object so that it did not hit the bottom of the cup. Pour your solution into the glass or jar.
Place your jar or glass in a location where it won’t be disturbed.
You can see above the solution is so thick you can’t see the branch through the liquid. Below, you can see how the crystals are forming and the solution is settling. You can see the branch better.

SNOWFLAKE SALT PAINTING

MATERIALS NEEDED

Snowflake stencils (click here to download)
Elmer’s glue
Salt
Blue food coloring (or any color of choice)
Water
White card-stock or watercolor paper

PROCEDURE

Print out the snowflake stencils. Then lay out a piece of paper over the
snowflakes as a stencil or you can use the printed snowflakes patterns.
Use the glue to draw over the snowflakes, making sure to do each small arm of
the snowflake.
Put a good amount of salt onto the glue and then carefully pour the excess salt off.
Let the glue and salt painting dry.
Mix a few tablespoons of water with blue food coloring
Use a pipette to slowly drip the coloring onto the salt painted snowflakes. Try not to drench the patterns but rather watch the salt soak up one droplet of color at a time.

MAGIC MILK + sOAP EXPERIMENT

MATERIALS NEEDED

Full Fat Milk
Blue Food Coloring
Dawn Dish Soap
Cotton Swabs
Snowman Cookie Cutter

PROCEDURE

Start by pouring your milk into a baking dish or other flat bottom surface. You don’t need a lot of milk just to cover the bottom and then some.
Then place the snowman cookie cutter in the the milk.
Next you want to fill the top of the milk with drops of color! Go ahead and mix them all up. You could also throw some glitter in there too, but that’s optional.
Pour a bit of dish soap into a small bowl. Next, touch your cotton swab tip to the dish soap to coat it. Then bring it over to your milk dish and gently touch the swab to the surface of the milk! What happens?

Remember, you can repeat this simple color changing milk experiment with different types of milk. What happens? Do you get the same effect or does it change?

THE SCIENCE OF COLOR CHANGING MILK

This magic milk science project gets it’s burst of color from chemistry…The chemistry between the dish soap and the fat in the milk is what makes the magic happen. While some of the dish soap’s properties dissolve in the water, the other properties search out the fat of the milk.

Milk is made up of vitamins, minerals, proteins and fats. When the soap is added to the milk is breaks apart the protein and the fats. The soap heads for the fats creating the cool bursting of color. When there is no more movement, all the fat molecules have been found. Are there any more hiding? Try another q-tip dipped in soap!

Turn it into a science experiment: Explore other varieties of milk including reduced fat milk, heavy cream, and even alternative milks!