We let them play for a few minutes and then led them into a discussion on why some boats floated better than others.
Finally, we extended it by laying pennies on the boats and seeing which could hold the most pennies. This was a fun experiment (who doesn't love playing in water) and will also be a great one to revisit when Miss M is older. You can see more pictures over at Homeschooling the Cameron Clan.
Baby B spent the morning playing, but was ready to fish the boats out if we needed.