Tuesday, August 18, 2015

Exploring Water & Dissolving in Science Club, Jr.

I led my final Science Club, Jr. program of the summer last week. The program has gotten such a great reputation that we had a huge combo crowd of folks who had registered in advance and folks who showed up day-of with a big interest in participating. And while I need to work with my fellow youth programming staff to work out the finer points of our registration/latecomers/walk-ins policies, I was glad to be able to allow 15 families--not just kids, as per usual--to participate. It was crowded, sure, but everyone was happily engaged in doing science.

In this particular program, I wanted for us to explore some of the properties of water. Or, more specifically, how some substances will or won't dissolve in water. To kick off our program, we shared a read aloud of The Gingerbread Man. This picture book choice may seem odd at first glance, but recall the story: the gingerbread man meets his ultimate demise because he must trust a fox to carry him across a river--a river which would cause him to fall to bits should he try to swim.

Photo by Skokie Public Library (CC BY-NC-SA 2.0)

So we read the story, then we talked about what we observed happening. I was interested to discover that, when we started talking about why the gingerbread man couldn't swim, many children said that if he swam he would have melted. I would not have anticipated that bit of kid logic, although it of course makes sense to me in hindsight. This reasonable misconception opened the door for us to talk about what the word "dissolve" means and to practice saying it.

Photo by Skokie Public Library (CC BY-NC-SA 2.0)
After we had the nuts and bolts of the concept of dissolving substances, we moved to our hands-on experiments. Each station was prepped with the following:
  • a bowl of water
  • a small cup with salt
  • a small cup with fruit punch powder
  • a small cup with a few Skittles candies
  • a small cup with a piece of graham cracker
  • a popsicle stick for stirring

Before we really got to experimenting, we talked about how we could tell that the liquid in our bowls was water. This line of questioning helped reinforce that scientists never drink or eat a substance that they don't know what it is. It's never to early for science safety skills!

The first phase of the experiment was for kids to dump the cup of salt in the water and observe what happened. Kids were invited to stir their mixture with their popsicle sticks if they so desired. End result: the salt dissolves!

Phase two was dumping the fruit punch powder into the water to observe what would happen, again with optional stirring. This time around, only some of the substance dissolved. We were able to tell some dissolved because the water turned the color of the powder, but we could also see some undissolved powder on the bottom of the bowls. This allowed us to introduce the concept of saturation, when no more of a substance can dissolve in a liquid.

Advice: if at all possible, dump the bowls and refill with fresh water at this point.

Photo by Skokie Public Library (CC BY-NC-SA 2.0)
Phase three was placing the Skittles candies in the bottom of the bowl. We just observed to start off, watching what happened to the colors of the candies as they sat in the water. The colors will bleed from the candies, ultimately leaving a white candy at the bottom of the bowl. Before giving everything a stir for good measure--because who can resist, really?--we talked about reasons why the color might come off but the whole candy might not dissolve.

Our fourth and final phase of the experiment was the graham cracker, which most closely resembled the gingerbread man of our story. Once again, after placing the graham cracker in the water we observed. Kids were interested to see how the graham cracker became visibly soggy before ultimately coming apart in pieces. I heard some great parent/child conversations about what this experiment suggests about dunking cookies in milk at home.

All in all, this was a great program--not too messy, easy for antsy young scientists to do the activities more quickly with their caregivers as desired, and a concept that kids encounter but didn't necessarily have the vocabulary to explain. It was a great summer for Science Club, Jr.!

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