CK-12 Foundation
Don't Slip
Salt is the go-to material when people need to melt ice—learn the chemistry behind its effectiveness with an interactive lesson. Pupils watch a short narrative and then explore the concept through a simulation. Young scientists...
Howard Hughes Medical Institute
The Making of the Fittest: Got Lactase? The Co-evolution of Genes and Culture
Got milk? Only two cultures have had it long enough to develop the tolerance of lactose as an adult. Learn how the responsible genes evolved along with the cultures that have been consuming milk. This rich film is supplied with a few...