So the students were really thinking hard...and it caused us to change our model yet again, especially as we gained more evidence from combining two models we've established. We know how filters work, and we know how a substance dissolves.
So if water moves through any hole, in any filter, isn't that evidence to suggest that water, like citric acid (or any other substance we looked into) also is made of pieces, too? The only way it can go through something is if it's able to "break apart," and it also flows really easily, so it must be made of pieces, too. We also know that when a substance dissolves, it moves everywhere in a liquid, so if water wasn't made of pieces, with little tiny spaces in between the pieces, then it wouldn't go through and fit down to the bottom (or the sides), which we know it did from tasting everywhere from the cup!
We took these ideas to mathematically prove the substance isn't gone when it dissolves, and that water is made of pieces, or particles too small we can't see.
So this got us thinking...if there are things super small in the water, and filter holes aren't small enough to catch them, how do they really clean the water? This is getting us thinking about new questions that relate back to our Driving Question for the unit--Where does my clean water come from and where does it go once we make it dirty?
So if water moves through any hole, in any filter, isn't that evidence to suggest that water, like citric acid (or any other substance we looked into) also is made of pieces, too? The only way it can go through something is if it's able to "break apart," and it also flows really easily, so it must be made of pieces, too. We also know that when a substance dissolves, it moves everywhere in a liquid, so if water wasn't made of pieces, with little tiny spaces in between the pieces, then it wouldn't go through and fit down to the bottom (or the sides), which we know it did from tasting everywhere from the cup!
We took these ideas to mathematically prove the substance isn't gone when it dissolves, and that water is made of pieces, or particles too small we can't see.
So this got us thinking...if there are things super small in the water, and filter holes aren't small enough to catch them, how do they really clean the water? This is getting us thinking about new questions that relate back to our Driving Question for the unit--Where does my clean water come from and where does it go once we make it dirty?