Recognizing that freshwater from the Chicago River eventually reaches the Mississippi River and dumps into the Gulf of Mexico, we were starting to wonder not only why this was the case (because all that fresh water would become salt water like our model showed us), but we also quickly realized just how much more salt water there was than freshwater!

Like we really thought the Chicago River was big and that Lake Michigan was big, but compared to the size of all the oceans, the river system was super tiny and the Great Lakes small compared to the size of the oceans on the Earth!  This visual REALLY got us thinking...

There's so much salt water, and very little freshwater...but how much of each is there?  Doing some research and math, we figured out the following:  

Whoah!  If 98% of the Earth's water is salt water, and the other 2% is freshwater, how can we really see what this looks like?  Fifth graders were asked to represent this mathematically, and we got some really cool ideas!

So if there is so much salt water, is this the water we use to drink?  How exactly do they get the salt out?  We turned to research again, and apparently  you can boil the water to get the water out of the salt water...

We've had questions where we get our drinking water from (as this was how we launched our unit when we all washed some dirty dishes) and it seems like this can't possibly be the way knowing it takes so long.  But maybe it is???

With Mrs. Brinza's help, we built out a landscape with some garbage bags and some toys she had laying around in her remote learning workspace (her kids' playroom)!  We added water to it to see what would happen. Here's what we noticed:

1.  Water always goes down to the lowest point. 
2.  It seems to pool where there's no slant.
3.  Water droplets join other droplets and kind of make rivers downwards at they flow.

While we initially thought wind got water flowing (and it might), Mrs. Brinza had no wind in her playroom, so we're thinking that it's just the slope that gets water flowing.

We decided the best way to figure out how the water flows in Chicago (like which direction) was to see if the land was sloped, and we're thinking it's not since Chicago is so incredibly flat.  But with some elevation data for Chicago and surrounding areas, we're seeing that the land is actually sloped, which means the water does have to flow!

With all the data, we see how the water is flowing towards the Gulf of Mexico, and using Google Maps, we confirmed this!  But now we're thinking...what does this really mean?  Doesn't all our treated water, that's 99% clean from our wastewater treatment facilities end up in a body of water that has salt in it?  What does this possibly mean?

Now that we agree what it means for a substance to dissolve, we returned to the wastewater treatment facility to realize we really didn't know how they could get out all the dissolved solids (and harmful bacteria from waste)!  So as we revisited our investigation ideas, we realized that our local wastewater treatment facility has made a virtual tour due to it being closed for tours due to the pandemic!  So we got a glimpse to go inside ours! 

After discussing what went on there, we realized we didn't understand a lot of the process, and did some more research and breaking down of some words that stumped us!

From here, we revisited our consensus model only to realize we absolutely knew how they treated the wastewater, but we had no clue what they did with it!  So we turned to Google Maps to help us locate the nearest waterways to the three wastewater treatment facilities here in Chicago!

We narrowed it down that each facility dumps the treated water into a river.  We've got some questions about this as:

1. Why would they work so hard to treat the water if it's still not safe to drink?
2.  Why do they dump it into a river?  Rivers are not safe to drink! 
3.  Is there another place that cleans the water we drink?
4.  Where does the river lead to? Does it go to the place we get our drinking water from?

SO MANY QUESTIONS!

With all this discussion around particles and dissolving, we're starting to see some patterns!  We've noticed that our dirty water looks so dirty because there are probably LOTS of solids that have dissolved in them!  We continued to focus this week on what it means for a substance to dissolve, practicing with salt, sugar, and a favorite this time of year--citric acid (it's found on the outside of Sour-Patch-Kids).  We tasted samples of water with salt dissolved in it and even used a scale to prove that the salt was still there!

With all this focus on dissolved solids, we're going back to where we had a lot of questions--what exactly happens at the wastewater treatment facility to get out everything from the dirty water?  If there are so many tiny, tiny particles in the water, how exactly do they get them out?

With our big AHA! moment coming in regards to the evidence showing us that water must be made of particles (and even smaller ones than the dirty stuff in the water), we reflected upon the models some students developed:  

We then went back to the drawing board to realize that all the models we've developed before could be improved with the evidence we've figured out regarding particles.  One of our investigation ideas was also to use a microscope to help us nail down what, if anything was still in our water, and by reaching out to the scientific teaching community on Twitter, Mrs. Brinza found a teacher with a microscope willing to help!

This got us thinking about how we could represent water, and anything that might be added to water in a new, improved way.  So we worked through a discussion determining:
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From here, students were asked to try and model their dirty water again!  We're really trying to figure out what's in our dirty water so we can better determine just how they clean it at the wastewater treatment facility.  

Knowing that many of the particles can't be seen, we're starting to think of what's actually happening to these particles in the water, especially since they can be seen at first and then seem to disappear over time.  We've got lots of ideas about what's happening to these substances made of particles, which include:

1. They're melting.
2. They're dissolving.
3. They're disintegrating.
4. They're disappearing.
5.  They're turning into something new!

Check out all the ways these students have modeled this:
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And by watching a microscope video, doing a taste test, and using a scale, we're figured out the following about what happens when a substance, like salt, enters the water and disappears.

We've got some consensus-making to do!!!  So exciting!