For an activity to explore buoyancy—what materials and which objects sink or float in water—I gave each child in a small group an object to hold. Then I explained that we were going to think about the objects and say where we think they will come to rest in a big tub of water—at the bottom or near the top of the water—BEFORE we put the objects in the water. Most of the two-year-olds are in the “thought is action” stage and immediately dropped (threw, in some cases) the objects in the tub. “I think it’s going to…It’s floating!”
The four-year-olds seemed to savor their anticipation of “doing”. They took their time to tell where they thought the object would come to rest before testing their prediction. It’s wonderful to work with children who are not afraid to be “wrong”. My hope is that I do nothing to change that.
Pumpkins are fun objects to use in this activity. Children often predict that the largest one will sink, even after witnessing the smallest and the medium pumpkins floating. Children can record their results by drawing the pumpkin shape on a teacher-made template of the tub.
Some children may notice and explore the effect of magnification, especially if the tub you use is round.
Read the October Teaching Through Tradebooks column, Pumpkins! By Karen Ansberry and Emily Morgan for more pumpkin exploration (grades K-6) with literature connections to How Many Seeds in a Pumpkin? by Margaret McNamara and Pumpkin Circle by George Levenson.