11 Feb A Super Simple Salt Water Evaporation Experiment

As part of the science component in our study of the book Very Last First Time, we decided to look at some of the properties of salt water.  Our first experiment was to look at how evaporation would separate salt water.

Salt Water Evaporation Experiment

This super simple salt water evaporation experiment is a very basic experiment, but I wanted to introduce the Scientific Method right from the beginning.  We started very basically; I figured it was probably age-appropriate to cut out the research step.  I did a short search but didn’t come up with exactly what I was looking for, so I created my own form:  “My Scientific Experiment, ” which you can see at the bottom of this post. You are free to download it HERE, if you like.

What You’ll Need:

We started with a small bowl of water and some salt.  Clark observed that the water was clear.  He drank a spoonful of it and said it was good.

The Process

Then I had him add a ton of salt.  I’m working at letting go of control, so I just let him dump as much as he thought was appropriate into the bowl.

Clark then stirred the mixture until the salt dissolved. You can do this experiment on the stove. I’m sure that was quicker, but it would have been more restrictive and I really want Clark to be doing the work, not me!  Either way, the salt eventually completely dissolves in the water.  It may just take some patience.

Our Observations

Once the salt dissolved, the water remaining was fairly clear.  Clark wanted to taste it.  Let’s just say that didn’t end well and we had to have a conversation about spitting.

Evaporation Takes Time

We watched the bowl of water over several days, observing how the water was evaporating more and more each day. If I were to do this again, I would draw a line with a dry-erase marker to keep track of the level of the water.  After a week of casual observation, we sat down to make our official observations and conclusions.

We saw some pretty big changes.  It was interesting to watch Clark.  I just let him verbalize his observations and explore.  He noticed that the salt was all the way to the top of the container and that about half of the water had evaporated.  There were many questions.  “Why does the salt not evaporate along with the water?”  “How come there are big chunks of salt in the bottom of the bowl?”

Clark even decided to taste the water again, which surprised me, because he certainly didn’t like the last taste he had! It was surprising to him that the water tasted almost normal. When he tasted it again, he went to the bottom of the bowl and picking up some salt.  “YUCK!”

He also tried the salt caked onto the side of the bowl.  Yup!  Very salty!

We talked about how the evaporation left behind the salt and how this happens in the oceans, too.  A little research taught us that 80% of the world’s evaporation is due to the oceans evaporating.  Together, we learned that much of the world’s table salt is produced within evaporation ponds, which is a technique that has been used for thousands of years.

My Scientific Experiment Form

We finished our experiment by completing our Scientific Experiment Form.  Clark’s assignment was to describe the experiment and the results.  “We got a bowl and put water in the bowl and salt in the bowl.”  “The next day we saw that the water had evaporated.  I saw salt on the side of the bowl.”

Obviously, this was a super-duper simple experiment, but it was an introduction to the Scientific Method and Clark got interested in it, nonetheless.  Now I’m just hoping that salt comes off that bowl with a little soaking.

Don’t miss our complete Five in Row:  Very Last First Time study with lots of activities and more experiments.