In this activity, students are instructed to build a tower using kitchen sponges and toothpicks. They draw their tower in detail, then deconstruct it. Next they build it again using the drawing, but must change one variable, e.g., use a different type of sponge, or paperclips instead of toothpicks. Everything else must remain the same so that they can see the effect of this change. A downloadable set of instructions for the teacher is provided.