Why do we have blood and what does it do?

Younger people have lots of questions about older people, like: Why do we age? Why do people get gray or white hair? Why do older people have wrinkles? Why do older people have veins that stick up? Why are older people more tired? Why do some people get shorter as they get older? Dr. Suvi Neukam, a geriatrician at Oregon Health and Sciences University, answers kids’ questions about aging in this episode.

Why do birds fly? How do raptors soar? Why do some birds fly in the shape of a V? Why can’t some birds, like penguins, emus and ostriches fly? Why do hummingbirds fly so fast? We answer all of your questions about birds and flight with help from Anna Morris of the Vermont Institute of Natural Science and Bridget Butler, the Bird Diva. And we get a preview of our new education series But Why: Adventures! Northeast Nature. Educators: learn more about But Why: Adventures! Northeast Nature and sign up for free access to the series! Download our learning guides: Video |  PDF | Transcript

Sun bears are the smallest of the world’s bears, and among the least well-known. We learn about sun bears with the head of the Bornean Sun Bear Conservation Centre, and then explore why some other types of bears hibernate during winter months. Plus, we get treated to A Bear Song by Key Wilde and Mr. Clarke!

It's all about bikes in this episode of But Why? How come bicycles stay up when you're riding, but fall over once you stop? We turn to Andy Ruina, professor of engineering at Cornell University, for the scientific answer. We also learn how a bike chain works and Olympic mountain biker Lea Davison tells how to get started when riding. Download our learning guides: PDF | Google Slide | Transcript

11-year-old Alaska (from Colorado) wants to know: why do some kids love reading while others don’t? We know there’s a lot of debate lately about the best ways to teach kids how to read. But in this episode we leave the pedagogy to adults and let kids share with one another why they love to read and their best tips for kids like them, who may be struggling to learn (and love) to read. Plus, guest Fumiko Hoeft, medical doctor and professor at the University of Connecticut and at the University of California San Francisco, lifts the lid on our brains to explain what’s happening inside us when we learn to read. Dr. Hoeft runs a brain imaging research program and a lab called BrainLENS. Download our learning guides: PDF | Google Slide | Transcript