Kids didn't have huge backpacks when I was their age. We didn't have backpacks at all. Now it seemed all the kids had them. You saw little second-graders bent over like sherpas, dragging themselves through the school doors under the weight of their packs. Some of the kids had their packs on rollers, hauling them like luggage at the airport. I didn't understand any of this. The world was becoming digital; everything was smaller and lighter. But kids at school lugged more weight than ever.

Grant knew that people could not imagine geological time. Human life was lived on another scale of time entirely. An apple turned brown in a few minutes. Silverware turned black in a few days. A compost heap decayed in a season. A child grew up in a decade. None of these everyday human experiences prepared people to be able to imagine the meaning of eighty million years - the length of time that had passed since this little animal had died.

Although knowledge of how things work is sufficient to allow manipulation of nature, what humans really want to know is why things work. Children don't ask how the sky is blue. They ask why the sky is blue.

Physics was the first of the natural sciences to become fully modern and highly mathematical.Chemistry followed in the wake of physics, but biology, the retarded child, lagged far behind.