1. Another wastewater treatment facility!
2. More sewer pipes
3. A body of water
4. An aquifer underground
Here's what students predicted was the destination for the mystery pipe:
1. Another wastewater treatment facility!
2. More sewer pipes
3. A body of water
4. An aquifer underground
Using resources from the City of Chicago, we figured out a lot!
Of course we were concerned that when the TARP/Deep Tunnel gets too full during heavy rains and/or heavy usage of water, that our local waterway (the Chicago River) would end up with sewage in it. Of course this is a reality, so we began brainstorming ways we could help solve some problems associated with our sewer system.
Now that we know that nearly one-million gallons of water are removed from Lake Michigan every minute to be our source of drinking water, we realized that it has to refill somehow...otherwise, the lake would disappear relatively quickly, right?
So with lots of ideas thrown out there (rain, other bodies of water, underground sources, pipes, etc.) Mrs. Brinza turned each student a water particle and set them out on a journey! Using a die we had at home or an online dice, students moved from location to location and created a pathway for their journey!
While no two paths were the same, we settled on three big ideas for how the lake could refill: infiltration from groundwater supply, precipitation from the clouds, and runoff from bodies of water or other nearby surfaces!
This got us thinking with the new stuff we figured out, it was time to update our model!
This leaves us with one more question...
Where does that mystery pipe in the sewer lead to!?!?!
Now that we've figured out so much about our clean water, it was time to update the model we've been adding to since September (yes...we've been working on this awhile but have figured out soooo much)!
Next steps: Figure out how Lake Michigan refills and that mystery pipe that's still just that...a mystery!
With a much-deserved two-weeks off, we were ready to get back to work and figure out just what happens with the water we consume and use in our homes! Before break, students convinced Mrs. Brinza to test some water at Lake Michigan. If we tested the water at the Lake (which is our source), and then test it again at our homes, it would hopefully tell us any differences between the water and ultimately what happens between them!
We first turned to Google Maps to see that there was indeed a structure down by the lake which confirmed that there's a place purifying the water. It's called the Jardine Purification Plant. Additionally, there was a little blurb of something out in the lake which we thought was a lighthouse, but with some research, we determined it was a crib, or like a giant straw to suck in water under the lake to the purification plant.
Between the two classes, we got pretty similar data which is helping us see the consistency in our investigation. We then had a discussion around what the increase/decrease/constant values we saw and came to an agreement: that the purification plant must add stuff to the water and it must also remove stuff! Just like we thought!
As much as we wanted to go on a field trip, we realized the pandemic is setting some limitations on this, but thank goodness there's a good video for what goes on at Chicago's purification plant, the largest in the world!
After an in-depth discussion, we truly built understanding as a class about what goes on there:
1. Screens remove debris (just like at the WWTF)!
2. Chemicals are added to kill bacteria (chlorine), help with oral hygiene (fluoride) and to make dissolved particles still in the water sticky and sink (alum).
3. Sand and gravel...yes! Sand and gravel help filter out any remaining particles...JUST LIKE GROUNDWATER! This was so cool to see!
We wrapped up our "figuring out" by comparing how our purification process is similar to what happens naturally in the ground.
Recognizing that the water we get comes from Lake Michigan, we also unanimously agreed that we would NOT drink it straight from the lake! We brainstormed all kinds of things that would be in the lake, including large things like trash (sadly) and fish (yikes) alongside smaller things like dissolved solids (animal poop for example). We even mentioned that there would be liquid pollution that would be hard to see amidst all the water particles.
We decided to model our thinking for what happens between Lake Michigan and our homes. Check out these ideas:
Comparing models, we agreed that there were pipes involved in the process connecting the lake to our homes. We also agreed that there needed to be some kind of filtering system to get things out of the water that didn't belong in it. We certainly had our differences though! Some classmates thought there would be a specific location to clean the water (like a wastewater treatment facility but possibly called something else--since water from Lake Michigan wouldn't be as dirty as water from the sewer system). Others though there would be a filtering system by each home. Others thought there would be chemicals added to the water.
We went back to our investigation ideas and checked off what new investigations we could do to possibly help us figure out what happens between the lake and the tap.
There was lots of talk about testing Lake Michigan water and compare it to the water from our tap. Here are some students' responses advocating for one investigation over another...
Recognizing that groundwater usage is more common than we think, we realized we had figured out a lot out about groundwater and were at a good point to put pieces together!
We know that the water deep in a well is clean enough to drink, and that the particles of earth above where the well is drilled are so packed together that only water seeps, or infiltrates through. We also recognized that special rocks, called aquifers, are rocks saturated with water and are actually located all over the US! The people who responded to us on Twitter mentioned they get their water from the ground, wells, or aquifers are highlighted on the map below. We realized that there's actually lots of aquifers all over the United States.
We still didn't really know how the aquifers continue to refill, especially in areas like Oklahoma or Texas that don't get a ton of rain annually. This video helps us see what infiltration really is, and how water continues to travel deep into the Earth over time, seeping in from bodies of water that may be close by or far away. We also saw how water can runoff surfaces. Also looking at a breakdown of groundwater vs. surface freshwater, we are seeing that there is WAYYYYYYYYYYYYY more groundwater than surface freshwater on the Earth.
Here in Chicago, we're fully aware that we have Lake Michigan near us and that we don't get our drinking water from aquifers, like many people across the US (and the world)! So if we wouldn't drink directly from Lake Michigan, what happens with the water from the lake before it reaches our homes and we use it for so many daily activities?
We're starting to see all these ideas come together and we're so proud of what we've figured out. An elephant can't fit through a hole that's too small for it to step through. The larger objects we put in our water to make it dirty that didn't dissolve got caught in our strainers. Mrs. Brinza's "toy" model showed us how empty space/gaps allow some things to get caught and others to pass through--just like the holes or empty spaces in filters. We're thinking the ground is a filter, too!
We also circled back to our Twitter post from Oklahoma. She mentioned that the groundwater had to get refilled when they used all the water. We're curious how this happens so we agreed we needed to figure out more about wells. When we found a well diagram, we were surprised at how different it looks like the "Jack and Jill" nursery rhyme picture many of us envisioned to be a well! And of course there was so much to notice and wonder about this well system!
While actually going to a well would have been an incredible field trip, we're limited by a couple things. One, everyone in the city uses water from Lake Michigan, so we couldn't really ask anyone here about wells. And we're still in the middle of a pandemic, so field trips are kind of out of the question. But we did find a great video resource helping us figure out more about wells, how they're built, and how they get refilled!
Seeing all these groundwater/water in the ground/well water similarities pop up on Twitter made us wonder if we really could get water out of the ground. We figured the best thing to do was to just dig...and this survivalist helped us see some amazing things!
So many of us had questions about how the water could actually be clean enough for the survivalist to drink (or anyone else that uses groundwater for that matter). We are focusing on scale, and returned to one of our favorite practices as scientists--modeling. We did a quick review of what we've figured out about particles and came to this agreement:
We then started thinking about the ground itself. We know that sand is made of little particles, but we started considering what would happen to those particles as we got deeper and deeper in the ground, like the survivalist. Through a lengthy discussion that we may have compared to a basket of laundry or a big pile of people wrestling on top of one another, we agreed that the things on the bottom of those piles would be super squished! This means the sand deep in the hole is super compacted with little space around all the particles!
We then wanted to see a working model--like a model that actually tried to show what happened when water was in the ground, trying to move through the sand particles. So since we're remote, we came up with some things Mrs. Brinza could use to help us figure this out. She's teaching from her kids' playroom, so here's what they worked through together with some everyday toys:
We are really trying to make sense of this, as it seems so odd that water deep in the ground (which we think is dirty, right?) can actually help clean water!
With all our figuring out, the class majority agreed that we must get our freshwater from somewhere else besides the ocean, since it's too far, to long of a process, and just way too expensive! We went back to our evolving model and updated it with the new ideas we figured out!
This naturally led to us thinking where we and others get our freshwater from! Students were asked to develop models to explain their thinking!
With so many ideas on the table for where various people get their freshwater from, we came up with three ideas to actually figure this out:
1. Go to these places and look around (but this really can't happen due to the pandemic, so we ruled that out).
2. Use Google Maps to look for freshwater sources near various places, and this could be an option during a pandemic, since it's safe to use Google Maps!
3. Find people who live in these types of places and just ask them!
We first agreed research would be okay to figure out where we get our water from here in Chicago. Both the Chicago River and Lake Michigan were overwhelmingly voted for, but the size of Lake Michigan determined our best claim. Research confirmed this!
So we used Google Maps and looked at places all over the country! We found some pretty interesting things:
1. There's nothing like Lake Michigan near ANY other part of the country. While places have freshwater, the bodies of water are really small and might not have the volume of water necessary based on what people use.
2. Some places have LITERALLY NO FRESHWATER. Like what do these folks do?
Mrs. Brinza also turned to Twitter for help--since her account is public and active, people responded to this post and messaged her privately, which was great!
This really got us thinking about where people got their water from and we summarized our findings on this map. So many ideas focused on water in places we hadn't even considered...like the ground. That's super weird...maybe we should focus on that next since lots of people in lots of different places mentioned that!
So if boiling salt water to get freshwater works...maybe there was something more we needed to consider.
Like just how far is the ocean from us? How much water do we use on a given day? How much would it cost to actually heat the water? We do have energy bills and we know energy isn't free. We dug a little deeper into all these questions we had to figure out some important ideas about salt water being turned into freshwater!
We did a lot of figuring out with many tools that are offered to use during remote learning. With Google Maps, we figured out that the nearest ocean is over 800 miles away...that's really far to get water!!! With an online water footprint calculator, we determined how much water we use on average and it's a LOT! And then with some energy cost analysis for the city of Chicago...HOLY COW! Boiling salt water from the ocean to get our freshwater would be nuts! That's just way to expensive! We have to get our water elsewhere...and people that even live near the ocean must get their water elsewhere, too! This process is just too long and too costly for it to be a reality for the majority of people. Back to the drawing board...where do people get their freshwater from then???