And now that students know the role that air and water have in the process of evaporation, they asked some really GOOD questions, too.

How come what happened to these ships doesn't happen to ships everywhere all the time?  With some research, students discovered that more of the water must have been removed from where the ships were before it could return.  And there you have it...the story of the ships in the Aral Sea.  

They concluded the unit using Google Drawing to create a comic explaining why the ships ended up in a field!  Check out these four!

Using an online model to show how air and water interact, fifth graders generated some good questions that show they are thinking about the relationships between air and water that can possibly explain how the ships ended up in a field. 

We put our thinking to the test when students then had to engineer their own models. ​

Our big findings were this:
Temperature and particle motion are related!
1.  The higher the temperature, the more the particles move.
2.  The more they move, the more space that surrounds them.
3.  The more they move, the more they collide with other particles around them.

When air collides with the particles of water on the surface, they can knock the water particles into the air (and they're already colliding with each other as the water heats up).  When water moves into the air, it becomes a gas.  This process is called evaporation.  

An important practice in scientists' work is to develop and use models to explain their understanding of scientific phenomena.  Using a computer simulation, students are seeing how the particles that make up ice and water are the same, but that the speed at which they move and the space around them makes the properties of those two substances unique.  We're relating the phase change of solid and liquid to the state of matter of a gas.

Using a syringe system, students are discovering that like solids and liquids, gases take up space and have weight, too, yet how they behave is different.  We're developing a consensus model of how air must behave.  It's a work in progress, and making our thinking visible is difficult, but what we uncover can hopefully help us better explain how these ships could have ended up in a field, especially since the water isn't heated.  Our claim that the water evaporated isn't necessarily making sense now, but with time, we can hopefully explain our ideas better.  We must gather some evidence first!

Fifth graders continue to track their mini-lakes, gathering evidence on both the volume and the weight over time.  Students are beginning to notice that both the weight and volume are decreasing, and this is helping students to better understand the ideas behind evaporation.

Since we've considered what happens as water is heated, we're also thinking about what happens as water is cooled.  

​We've also tracked water's weight and volume as it freezes and then melts, discovering that the mass stays the same and that the volume increases as it gets colder and returns to its starting level as it melts.   

So if the water droplets appear to get smaller, is it possible to show that they can do the reverse, and get larger?

Designing an investigation with hot water, graduated cups and plastic wrap, fifth graders are gathering evidence that the water must be in the air when it evaporates.  Why?  Because it ended up on the plastic wrap.

Our current thoughts....
1.  Water must move.  That's weird, because it's a non-living thing.
2.  Our water was hot.  Does this happen with cold water or room temperature water?  Our lakes we built (or a real lake for that matter) are not hot.  This gets us thinking...

This also means we have to investigate what salt does to the water, since it's going to "throw" our data off.  With some carefully designing investigations, students recognized that salt can be crushed into smaller and smaller pieces, and over time, when added to water, can completely "disappear."  We gathered evidence to suggest that the salt was still in the water even though we couldn't see it because the volume of the water increased.  And all matter has both mass and volume!

This whole idea behind salt getting smaller and smaller is making us think about how water can get smaller and smaller.  Is it possible that water does this same thing?  And "disappear" like salt?  Does it go somewhere?

So over time, we saw the water droplets we sprayed on plastic cups disappear, and our hands inside the cups didn't get wet, so the water must have gone somewhere.  We're thinking that it went into the air, but we'll need to figure out a way to prove that!  

​Boy are we thinking!

After having an in-depth discussion as to how some ships could have ended up in a field, fifth graders decided the best way to test their ideas was to build a model lake, which we will refer to as a mini-lake.  We will track the changes in the lake over time both quantitatively and qualitatively.  Students agreed that measuring the lake's mass would be important as a way to gather evidence to support the idea that the water could evaporate.  Students also wondered if the water would just get absorbed by the sand.  So we agreed that if it didn't change in weight, that the volume of the water would change.  In addition to tracking mass, students will also track the volume of the water by looking at a mark they place on the side of the container.

As fifth graders kick off their unit on water transformations, they are seeing and explaining how these GIANT ships could have ended up in a field...right smack in the middle!  We'll be exploring water's transformations over time, and we'll even be building our own mini-models of what we think happened to these ships over time.  Check back soon as we dig deeper into our unit!