I'm hoping that Carrie or some other 'science' person will step in here, because that is not my strongest subject. However, I'll explain a bit more about what we did with the sinks/floats experiment.
My son's guess: Different material does different stuff.
I personally counted his answer as correct because the key idea in that box' is:
When an item is placed in the water it pushes down on the water, but the water pushes the item back up. Heavier items sink, and lighter items float. I read this to them so they would hear the first part too, but I thought his answer was a pretty good guess, though it could have been a bit more specific.
Here is my daughter's guess:Some things are heavy, and some things are not heavy enough to sink.
Her answer is a bit more specific, and closer to what is written in the 'box' for the key idea. She is our resident 'scientist' (well, besides Daddy) and seems to 'get it' more easily.
I do understand what you mean about what ds said about the boat not sinking...it's obviously heavy and large, but is built in a way so that it won't sink. We actually just did (ds 5 and I) an exploration activity today having to do with the Ark. We put several things, some light and some heavy, in water to se if they would float or sink. We had fun wih it, and it was interesting to see, and watch him realize, that just because something is light it still may not float. Our paper clip sank and so did the cotton ball...which has to do with the material those things are made from. Larger items, like the lid we used, floated. He even had the idea to put everything in the lid at the end to see what would happen...it did float until he placed the last item...then it was too heavy. We also experimented to see what would happen if water got into something (like the lid, the measuring spoon, the marker lid), and then related that to what could have happened if water had gotten into the Ark...and of course how God told Noah just how to build it, which was the key idea for that 'box'. So, I believe it's okay to deviate from the experiments too, and add something of your own...it's about those teachable moments and answering the questions they have the best way you can.
Anyway, this is a much longer answer to your question that may not be helpful, but that's how we did it. I hope it has helped at least a little bit. Maybe others can clarify better.
Just as an aside; I am really enjoying these experiments! As I said, Science has never been my strong suit, and I am learning along with the kids. It's helping me to really think about things, and get into the subject. I love it!
