Engage your Children’s House class with these Sink & Float card sort can work well individually as well as an addition to other units and can be extended in various ways. Perfect for K (kindergarten), 1st (first) grade, 2nd (second) grade, and 3rd (third) grade. Originally developed for use in a Montessori classroom, but these are ideal for science centers with any K - 3rd grade students. These materials make an excellent springboard for further research. The materials can be used for 3 dif