The weather forecast says we’re headed into an extended spell of cold weather, with freezing temperatures predicted for the end of the week. So, it’s time to put some water jars on the front porch to see what happens. This year we’re going to be a bit more organized than usual and set up the jars as an experiment. There are reasons we’re setting it up this way, but we’ll let you try to figure out what those reasons are (with a few hints at the end of this post).
First, here’s our experimental setup: Four PLASTIC jars of water set on our front porch rail this afternoon, here in Oak Park, Illinois:
Jar A, on the far left, was filled with cold, fresh tap water. It’s lid has holes in it, so air can get in.
Jar B, just left of center, was filled with warm, fresh tap water. It’s lid also has holes in it, so air can get in.
Jar C, just right of center, also was filled with warm, fresh tap water. It’s lid has NO holes in it, so NO air can get in.
Jar D, on the far right, was filled with cold tap water, then a couple of handfuls of rock salt were added — the same kind of salt you may put on your steps or sidewalk when it snows. It’s lid has holes in it, so air can get in.
So, we are experimenting with the following variables:
- Does the water start out cold or warm?
- Is the water exposed to the air or not?
- Is the water fresh or salty?
Why do we want to experiment with those variables? Maybe you can guess if you check out these blog posts from last winter:
And now, here’s the big challenge:
What do you think will happen to each jar once the weather gets really, really cold?
You will need a separate guess — or “hypothesis” — for each jar, A through D. You can list your hypotheses in the comments section, below, or send them to me by e-mail (email@example.com) or Facebook.
Think hard, and good luck! (Or should I say, “good skill”?)
Note: I revised this post later the same day to make it clear that the jars are made of plastic. (Although it might be fun to try it with glass some day. Fun in a Mythbusters kind of way….)
To find out what happened on December 4th, when the air temperature dropped below freezing, please go here: https://neighborhoodnature.wordpress.com/2009/12/07/first-hard-freeze-for-our-jars-of-water/