A couple of months ago, Alex acquired a water filter. A small one, obviously, but a working one designed to demonstrate how water filtration works. The system has three layers — containing stones, sand and filter paper respectively — and when you pour the dirty water into the top, cleanish water drips out of the bottom.
A couple of weekends ago, we finally found the time to set it up. So set it up we did and I gave the twins a beaker of water and told them to dissolve a little bit of soil in it.
They excelled themselves.
Then the time came to start filtering:
Of course, there is only one way to test the results.
And before anyone asks, I did cheat a little bit for the final photo. The filter certainly did a good job of clearing the water, but was nowhere near effective enough to clean the findings of a pair of determined eight-year-olds.
I removed that last bit of cloudiness by replacing the filtered water with tap water.