Great for teaching that density depends of both mass and volume, students can't seem to put these spheres down! Two steel spheres are great for teaching the skills of observation and deduction.

Although these two stainless steel metal spheres have about the same mass, one has a diameter of 3.49 cm and the other a diameter of 12.7 cm, making their densities vastly different. Seeing the large hollow one float in water seems unbelievable to students.

Includes suggested activities sheet.