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:
The Magnatiles represent the sand particles, the Rummikub tiles were salt, and the blue pony beads were water. Putting the cardboard on an angle, we attempted to put more space between the sand particles at the top (where the sand is loose) and less space near the bottom (where the sand particles are squished). When Mrs. Brinza "poured" the salt water into the ground, we began to see two things:
1. Larger space at the top allows both salt and water to flow downwards. 2. But as the space between sand particles reduces as you go down, the bigger salt particle gets stuck and the water seeps through. It looks like there's only clean water at the bottom...and that's where the survivalist drank from! |
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!