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Shorter days might mean feeling stuck inside for more hours of the day, but that doesn’t have to limit the number of science activities that can keep kids engaged! This week, we’re sharing five of our favorite science experiments that allow kids to explore different aspects of the colder, snowier season.
Sounds like magic—but science can show you how it’s done!
Ingredients: water, salt, ice cubes
Supplies: three bowls, a piece of string
Set up the three bowls next to each other. Fill one with some salt, one with some water, and one with ice cubes.
Place a few of the ice cubes into the bowl containing the water.
Hand your assistant the piece of string, challenging them to lift a piece of ice from a bowl of water using only the string.
Next, offer them the bowl of salt and ask what they think might happen if they sprinkle it on the ice.
Place the string on the ice and sprinkle salt over the string. Wait 60 seconds, and try to lift the ice cube again.
What effect does salt have on the ice? Water freezes at 32° F (0° C), but when salt touches the ice, it lowers the freezing point to much lower than that. In order for the ice to melt, however, it has to absorb heat, so it absorbs heat from what’s around it, which in this case was the water near the ice cube. Some of this water becomes so cold that it refreezes and the string becomes trapped.
Suggestion for more science: Try using different-sized salt such as rock, epsom, and table salt, to see their effect on the time it takes the water to refreeze around the string.
Now that you’ve seen how ice can absorb the heat of what’s around it, use that observation to make a guess as to what types of materials, when placed around the ice, will encourage or prevent melting. In other words, what material makes the best insulation?
Supplies: insulating materials (suggestions include: styrofoam, bubble wrap, various kinds of fabric, pom pom or cotton balls, straw or hay, small towels, wood shavings), various containers for your various insulation materials with lids (think Tupperware)
Ask your kids what materials, or combination of materials, they want to use to insulate their ice cube. Pack the materials into each container, adding one ice cube. Make sure to keep one container without insulation to use as a control.
Draw up a simple chart for recording your results, including one column for each material tested (see table as an example).
Set your insulated boxes in an area away from sunlight or another direct heat source. Check on the ice cubes every 10 min. and describe the amount of melting in the chart.
What material allowed your ice to last the longest? How does that compare with the control ice cube?
Oobleck, a non-Newtonian fluid, is one of the most interesting substances to explore hands-on. Oobleck doesn’t behave like a “normal” liquid—it has properties of both a solid and a liquid depending on the amount of stress applied. When stress is applied, the cornstarch and water mixture acts like a solid, but when constant stress is not applied, the mixture acts like a liquid. Freezing the oobleck creates a solid. As the oobleck melts, the consistency keeps changing, which allows for many opportunities to observe the changing properties over time.
Ingredients: cornstarch, water
Supplies: liquid watercolors or food coloring (optional); glitter (optional); bowl; spoon; ice cube trays, silicone molds, or a container to place in the freezer
Add about 1/2 cup of cornstarch to a large bowl.
Slowly add up to a 1/2 cup of water. Mix until you get the consistency you desire. If you add too much water, just add more cornstarch.
If desired, add food coloring or liquid watercolors. Food coloring has the potential to stain, but watercolors are usually washable.
Pour the oobleck into molds and place the molds in the freezer for at least a few hours. When you transfer the frozen oobleck to a bowl or other container, place a towel beneath the container to catch any drips as the substance melts.
In January, we learned how snowflakes form as they fall from clouds down to the earth. In this activity, grow your own snowflake indoors using pipe cleaners and borax!
Ingredients: water (to be boiled by an adult)
Supplies: wide-mouth jar, pipe cleaners/chenille stems, small piece of yarn or string, pencil, borax
Have kids twist the pipe cleaners to form the general shape of a snowflake. Keep in mind that the snowflake will need to fit inside the mouth of the jar, so trim if necessary, and be sure to keep one branch long; this will be the branch used to hang the snowflake.
Tie the yarn or string into a loop. Bend the long branch around the bottom of the loop and then twist the remaining onto itself.
Thread the pencil through the loop. Let the snowflake hang in the jar while the pencil rests on top.
Have an adult pour 3 cups of boiling water in a large measuring cup. Add 3 tablespoons of borax one at a time for each cup of water, stirring in between each tablespoon until the borax is dissolved.
Remove your pipe cleaner snowflake from the jar. Pour enough solution into your jar so the snowflake will be submerged.
Hang your snowflake in the jar as before and let it sit undisturbed for about 5 hours or overnight.
Suggestion for more science: You can use alternatives to form the crystals. Salt or sugar (prepared as a solution with the same ratio) will work just as well; however, it will take much longer for the crystals to grow.
Now that you’ve worked through all these cold experiments, do one that provides you with a tasty, warm reward: hot chocolate!
Ingredients: three packets (or more for more science!) of instant hot chocolate, water
Supplies: three heat-proof mugs, measuring cup, spoons, stopwatch or timer, thermometer (optional), notebook for recording results
Ask your co-experimenters to make a prediction: Which temperature of water would dissolve the hot chocolate the quickest: cold, lukewarm, or hot? Why?
Started by emptying one hot chocolate packet into each mug.
One mug at a time, test different temperatures of water, using ice cold water, room temperature water, and hot water (have an adult heat up water over the stove or in the microwave). Using a kitchen thermometer to measure the temperature of your water is a great way to practice reading a thermometer and adds more data to your experiment. After recording the temperature for each cup, measure and add 6 oz. of water.
Once the water has been added to a mug, start the stopwatch and begin to stir. Stop the stopwatch as soon as you notice that the hot chocolate has dissolved, and note the amount of time it took.
Which temperature of water was the most effective in dissolving the hot chocolate? Hot water has more energy than cold water. With more energy, the molecules in the water move faster, breaking down the hot chocolate mix quicker.
Suggestion for more “science”: Heat up more water so every experimenter can enjoy a hot cup of chocolate!
Check out hBARSCI’s ice melting plates kit. Each kit includes two plates, one aluminum, one plastic, used to demonstrate conductivity and heat transfer when pieces of ice are applied. Defying logic, the aluminum plate, which is cold to the touch, melts the ice faster than the plastic foam plate, even though both have equivalent temperatures. Although simple, the kit challenges students’ preconceived notions on concepts of heat and thermodynamics. The melting plates display quizzical properties when an ice cube melts on each plate.