Science on the River - A Punt Down the Cam. The river Cam runs through Cambridge, past the colleges that have been home to influential scientists for hundreds of years. This week, we drift down the river, picking up key scientists as we go. We discover how petals attract pollinators, how carbon sequestration could call a halt to climate change and how ketamine could help us find the root of schizophrenic delusions. Also, we explore how evolved enzymes could make chemical reactions billions of times faster, and learn of the ultimate fate of the universe with Astronomer Royal, Professor Martin Rees. Plus, in Kitchen Science we see how sunlight can start a fire and mirrors can cause explosions!