Chemistry doesn't have much to offer in the way of household names. But few kids get out of elementary school without knowing what H2O means.
Of course, water can, and almost always does, contain more than just molecules formed of two hydrogen atoms fused to an oxygen atom. You also find loads of ions (charged particles) in it, from iron, chlorine, sodium and other substances. Some of these are cations, meaning they have a positive charge (at least one more proton than electron), while others are anions, bearing a negative charge (with electrons outnumbering protons).
There's nothing wrong with most of these ions if they're, say, swimming around in your water glass. But for cooling the magnets used at the MagLab, they just won't do, because their charge would interfere with the operation of the magnet.
One way to remove these ions from the water is through an "ion exchange" process that involves funneling the water through resin beads, as shown above. Some of these beads draw out the cations, while the others draw out the anions, leaving the processed water ion-free – and ready to cool off our magnets!
We go through quite a bit of deionized water here at the lab. Some 400 liters a second are required to keep just one of our many magnets – our 45 tesla hybrid – cool!