By thinking about the concept of density and taking into account the research on children's ideas about this concept, the authors were able to unpack the typical sink or float activity and realize that it has students unscientifically making comparisons between objects by changing two independent variables (mass and volume) at one time. With this…

When Goldilocks finds three bowls of porridge at different temperatures in the three bears' house, she accurately assesses the situation and comes up with one of the most recognizable lines in children's literature," This porridge is too hot; this porridge is too cold; aahh, this porridge is just right!" Goldilocks' famous line is a perfect…