This week on Lost in Science, in the lead-up to Christmas — and before our official festive special — we’re diving into the archives to revisit two of our all-time favourite holiday stories. Cat crunches the numbers on Santa’s impossibly busy Christmas Eve, using maths and physics to reveal just how many children he visits (and how he might just pull it off). Then Stu takes us on a botanical adventure through the science of Christmas trees, exploring what makes them smell, sparkle and survive the season.