I've been trying to be good about doing one hands-on "lab science" type session per week with the twins (we usually pull Ruth and Anna into our sessions, too!). This week we're studying the matter and motion unit in our science books, so I immediately thought about this density column experiment. I remember doing it myself when I was their age and having a blast!
One of my goals this year was not only to get us caught up to grade level, but to establish good schoolwork habits (write neatly, do your work, read the instructions, etc), so before we began I had each kid bring their notebook and sharpened pencil over, and reviewed standards - neatness, show their work, etc. Some of us are naturally more neat than others, but all of us have to make the effort, lol! We paused between each step to let everyone record the results in their notebooks, and I also kept track of the results on a whiteboard.
We started off by weighing the same amoung of seven different liquids - water, salt water (we added about 2 tablespoons to every cup), molasses, oil, vinegar, wine (don't ask!), and syrup - basically every liquid we could find in the pantry. Using a postal scale, we measured 1/4 cup of each liquid and recorded the respective weights (I don't remember the results off the top of my head, lol, but they were each different). I very casually introduced the scientific method - hypothesize, experiment, gather data, form conclusions - and we had a lot of fun making hypotheses about what each liquid would weigh, how much the salt would change the density of the water, what the heaviest and lightest liquids would be, etc.
After recording the results, I told the kids we were going to "stack" the liquids and asked them to hypothesize about the order the liquids would take.
We built our density column out of a ruler and a cylindrical vase. Everyone took turns pouring about 1 1/2" of their favorite liquid into the vase and we watched it form into layers. We compared the actual results to our hypotheses - I think everyone got it right! - and then began dropping small items in to see on which layer they landed. Key? straight to the bottom. Paper clip? straight to the bottom (this surprised me... I thought it might slow down a little around the molasses/syrup layer). Ditto BB pellets. Airsoft pellets landed on top of the water layer; same with the crayon. The plastic poker chip (I know, I know, wine and poker chips?!?) hung out on top of the oil.
Overall, we had a fun day in the old science lab - I mean, the kitchen. :)