We started out by reading the book 'A Drop in the Ocean, the story of water' and then demonstrated a couple of the rain cycle processes to illustrate what happens.ziploc bag with the cycle drawn on the bag with permanent marker pen
Next we made clouds in a bottle using instructions from this great website and the children were amazed by this. You have to roll the bottle between every try to get rid of the condensation and look carefully as you release your grip on the bottle. What you see is a faint cloud very definitely forming as the pressure drops inside the bottle. What a fantastic way of showing the conditions needed to form clouds!sets of cards using clipart and laminating them before cutting them out and shuffling them. I drew a basic cloud line and ground line on a large A2 sized piece of paper and the children took turns choosing a card from the pile and placing it on the paper where they thought it went. As the game went along we added a house, rocks as we talked about groundwater, a well drawing on the groundwater, a drainage system, and lots of arrows showing the potential movements of water from one area of the board to another. I had considered that I was under prepared for this part of the session as I didn't have a pretty pre-drawn game board all well thought out in advance. As it happened it was the best way to do it as the children TOLD ME the links and showed me where the arrows should point as we went along and it was a really good learning exercise for them.
Enthused by their success the girls wanted to try layering the materials to see if all of them together produced cleaner water than individually. They set this up independently but in the end it produced filthy water as there was a sudden 'whoosh' and the net plugging the pouring hole gave way under the weight, leaving a hole through the materials. The girls were intrigued by this hole...... and chatted about how and why the water had gone through in that particular place.
All in all, although I felt under-prepared, and hadn't thought through the effect that the coffee filters would have on the experiment, it was the perfect set-up as it posed natural problems for the girls to think about and solve. It high lighted the importance of the design of an experiment and the planning, and that a failure doesn't mean disaster, it means thinking and adapting and testing again. The experiment was flexible enough that the girls could take it in the direction that they were interested in so was great for allowing them to take the lead instead of being narrow and one-directional. The happy occurrence of a bit of water erosion on the combined filter at the end could lead nicely onto other topics!