Praxis: Here comes the sun, catch it while you can

By Medicine Hat News on December 2, 2017.

I can hardly believe that the year is almost over; is it December already? Where did the time go? I guess my first realization that winter was nearly upon us was coming home from work the other day. I realized that I never even saw the sun once while I was in my office. This time of the year, many of us get up and drive to work in the dark and return in the dark, seeing very little of the sun each day. In order to capture some of that wonderful glistening sunlight while it is high in the sky, I thought we would make some sun catchers and at the same time learn about how crystals are formed. Let’s get started!

*Remember to ask an adult before doing this experiment.

Materials

– clear plastic lids (the more transparent they are the better)

– kettle

– heat proof bowl

– epsom salt

– water

– measuring spoon

– measuring cup

– kettle

– cookie sheet

– decorative string or ribbon

– single hole punch

Procedure

1. Punch a hole in the plastic lid(s) that you will be using. This is the hole you will be putting the string in so you can hang up your sun catcher.

2. Place the plastic lids on the cookie sheet on a nice flat surface where you are going to work and allow the sun catchers to dry.

3. Measure 1/2 cup (125 mL) of epsom salts and pour into the bowl

4. Have an adult help you fill the kettle and plug it in to boil.

5. Measure 1/2 cup (125 mL) of boiling water and pour over the epsom salts.

6. Mix together well.

7. Allow the mixture to cool slightly. Do not worry if not all of the epsom salts dissolve as you are making a supersaturated solution.

8. Using the measuring spoon fill the plastic lids about 3/4 full of the liquid.

9. Set the lids aside.

10. Depending on a variety of factors to how full you filled the lid, to how humid or warm it is in the location you place the sun catchers will depend on how long it will take for the crystals to form.

11. Check back often and see how the crystals are growing.

12. Observe the different crystal formations on the different lids.

13. Once the liquid has completely evaporated, you are ready to take the sun catcher, tie a nice piece of string or ribbon through the hole and hang it up to enjoy!

What is going on?

You should be able to find epsom salts quite easily at the local grocery store or pharmacy. These salts are actually magnesium sulfate. When growing epsom salt crystals, it is important that we heated up the water. The hotter temperature of the water allowed for more of the salts to dissolve into the solution. This is because the heat increases the amount of space available between molecules allowing for more salt atoms to dissolve.

It was also essential to make a saturated solution in order to start the process of crystal formation. This solution is called saturated because not all of the salt dissolved into the solution. You should have been able to see some of the salt still in the solution; likely sitting at the bottom of the bowl. You see it because all of the molecular space has been filled up and there is nowhere for it to go. When the solution cools, the space between the molecules decreases and the salt is pushed out. This is the first step in the formation of crystals; the process is further enhanced as the water begins to evaporate. Be patient, it may take a bit of time for these beautiful crystals to form. Be careful handling your sun catcher as the crystals are extremely fragile.

Patty Rooks is senior scientific consultant at PRAXIS, “Connecting Science To The Community.” Contact Praxis at praxis@praxismh.ca, http://www.praxismh.ca, Tweet or follow us @PraxisMedHat, or friend us on Facebook.

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