SALT LAKE CITY — Celebrate the season by trying out one of these fun, inexpensive and simple holiday STEM experiments.
What does a snowflake look like?
See for yourself that every snowflake is different through this simple outdoor experiment. Although all snowflakes have a similar hexagonal shape, other details can differ based on temperature, humidity and more.
Next time snow starts falling, go outside and catch a few snowflakes on a piece of black construction paper. You can observe the snowflakes with a magnifying glass or basic microscope. A 5x lens works for most snowflakes.
Questions to ask: How many sides or points do the snowflakes have? Try collecting snowflakes on another day. Do they look different?
Dissolving Candy Canes
Candy canes are great to eat, but the sweets are also fantastic to test out the scientific method.
For this experiment you will need paper and a pencil, a timer, three cups, three unwrapped candy canes and water (hot, cold and room temperature). Based on the different temperatures of water, predict and record which candy cane you think will dissolve the fastest and which will dissolve the slowest. Measure equal parts liquid into the cups. Set your timer and drop a candy cane into each liquid; observe what happens. Draw/record your observations.
Questions to ask: How did your prediction compare to your actual results?
Let's make frost!
The air around us is filled with water vapor. As the weather turns colder we can see this water condensing in the form of frost on grass, windows, cars, etc.
In this experiment you will create frost. Each person will need a clean and empty tin can (we used tomato sauce cans but larger cans work too), crushed ice, water, and salt. Fill the can about half way with ice. Add a little water and salt. Observe as ice crystals begin to form on the can. What's happening? Water and ice sit at about freezing temperature, but by adding salt, you're lowering the melting point of the ice. The surface of the can is actually below freezing point, so the water vapor on the air freezes on the can. (Note: do not try this experiment near a heater or on a warm day.)
Questions to ask: What happens if you add more water or salt?
Why do we salt our roads in winter?
When you add salt to ice in water, it melts the ice faster at first by using more energy and cooling the surrounding melting water faster. Check out the ice water in the first picture. The temperature reads about 36 degrees, which is only four degrees warmer than the point where water freezes and melts at the same rate.
Then salt was added. As you can see in the second picture, the temperature dropped about four degrees. This happened in just a few minutes. If you keep adding salt until the water is as full of as much salt as it can take, the temperature will drop even more.
Try it yourself: Get two small containers and measure the same amount of ice into each. Add the same amount of water to each until the ice moves easily. Stir as much salt into one as you can and wait a few minutes. Dip your fingers in each container. Can you feel the difference? In fact, a large amount of watery ice saturated with salt can drop to a temperature of about five degrees below zero!
When we add salt to our icy roads in the winter the salt dissolves and gets in the way of the water so water molecules can't clump together and freeze easily.
For a more colorful experiment, try putting put some water in a shallow pan and place it in the freezer. When it has frozen hard, take it out and sprinkle it with salt. As it starts to melt, brush some food color over the ice so you can see the salt and holes melting in the ice better.
Questions to ask: Why doesn't the ocean freeze over? What happens to water molecules when water freezes? Why does the water get colder when you add ice?
We love holiday lights! See how holiday lights work and create a mini circuit.
For this experiment we used recycled Christmas lights and a battery. Safety first: always do any electrical experiments with a responsible adult present and make sure your hands are completely dry.
You will need lights, an AA battery, a wire cutter/stripper and electrical tape. Cut the Christmas light so that you have 1-2 inches of wire on each side of the light. Strip the end of each casing so that you expose the copper wire. Tape one side of the wire to the positive side of the battery and tape the other wire to the negative side of the battery. If you've wired it correctly, the bulb will light up. Experiment with the connection if the bulb doesn't work. (Note: if you're using recycled lights, a broken light will not light up.)
Questions to ask: Why does the light go out if the wires aren't touching the battery? Does the brightness of the light increase with a more powerful battery?
Make a snowflake that won't melt
Try this experiment with household items to make some snowflakes that won't melt.
You will need: A box of Borax laundry soap (not Boraxo), wire cutters or tough scissors, four pipe cleaners, a container for your snowflake that will hold it without it touching the sides or bottom, a stick or pencil long enough to go across the top of the container, some monofilament (fishing) line, a cup measure, a tablespoon and some water.
Make a snowflake shape using the pipe cleaners by taking two of the pipe cleaners and cutting each into three equal pieces. If your pipe cleaners are 12 inches long, this means each cut piece will be 4 inches long. Bend the pieces into a V shape and then twist them together to make six points. Cut six 1-inch pieces from another pipe cleaner and twist those around the end of each arm to make the "Y" shape. Continue adding other shapes you like.
Take the finished snowflake and tie a loop of monofilament line around one of the ends and tie the other end around the pencil. The snowflake should hang about inch from the bottom of the container. Figure out how much water it will take to cover your snowflake completely by pouring water by cups into the container. Remove the snowflake and heat the water in a microwave or in a pot on the stove until it just starts to bubble. Remove from heat. For each cup of water used, add three tablespoons of Borax laundry detergent. Stir until all the Borax is dissolved as much as possible. The water will look milky and some of the Borax will begin to collect in the bottom of the container right away. This is normal. Hang the snowflake in the water and don't disturb the container for 8 hours. When you check it, the borax will have formed beautiful sparkly crystals on the pipe cleaner snowflake and the inside of the container. Remove the snowflake and hang it up to dry. If you want to make another snowflake, just heat the Borax to dissolve it and start over.
Questions to ask: What happens when you add more Borax to the container? What colors can you make the snowflake by adding food color? What kind of shapes do crystals make?
Carrie Rogers-Whitehead and Jennifer McKague are librarians with Salt Lake County Library Services (www.slcolibrary.org) and Susan Jeppesen with Davis County Library (http://www.daviscountyutah.gov/library). They all love doing STEM activities.