This week, instead of a normal episode, we're bringing you an episode from one of our podcast friends, Circle Round, from WBUR in Boston. Circle Round features folk tales from around the world, and we've selected one we think you'll really enjoy. French comedian Gad Elmaleh stars in "Armadillo's Song," a story about achieving goals and proving naysayers wrong!

Why don't spiders stick to their own webs? How do spiders walk up walls and on ceilings without falling? Why do spiders have eight legs and eight eyes? How do they make webs? And silk? What's a cobweb? How do spiders eat? And why are daddy long legs called daddy long legs when they have to have a female to produce babies?! We're talking spiders today with arachnologist Catherine Scott.

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Why do we celebrate Halloween? Who created this holiday? Where do pumpkins come from and why do we carve them? This week we're answering your Halloween questions with a professor of all kinds of scary and creepy things, Regina Hansen of Boston University.

In today's episode we're not answering any questions. Instead, we're going to talk with 11-year-old twins Isabelle and Sophie Posner-Brown. When Sophie was two, she was diagnosed with a malignant brain tumor. She's had three surgeries and lots of chemotherapy, but she's been on a break from chemo for the last four years. The twins talked with But Why about what it's like to live with Sophie's illness.

A cancer diagnosis can be scary, and for kids it can be bewildering. We've gotten some questions about cancer and in this episode we answer them with Dr. Donald Small, director of pediatric oncology at Johns Hopkins School of Medicine. We answer how people get sick when it's not caused by germs, how people get cancer, and why cancer "does not have a cure." There's nothing graphic or scary in this episode, but adults may want to give this episode a listen if cancer is something your littles have been dealing with.

We'll learn about the kinds of animals that live in urban environments and the challenges they face! One young Australian listener wants to know why wombats, kangaroos and koalas hang out in the countryside rather than the city. Dr. Mark Eldridge from the Australian Museum Research Institute tackles that one. And we turn our focus to one particular urban dweller, the raccoon, with York University raccoon expert Suzanne MacDonald. She lives in Toronto, which has one of the most dense populations of raccoons in the world. She helps answer why raccoons eat garbage, how long they live and why they look like they're wearing masks.

We visit Fireman's Hall Museum in Philadelphia and get answers to a dozen questions about fire from Philly firefighter Lisa Desamour. She tells us what fire is, why matches work to start fires, and why fire is often orange. Plus: how does water put out fire? How do smoke alarms work? Why do firefighters have Dalmations?

In this episode of But Why, we hear music from Music for Sprouts' Mr. Chris, Drummer Seny Daffe, and cellist Emily Taubl and answer questions about strings, percussion, and the magic of music itself. Get ready to dance.

Why do turtles need shells? Why do turtles move so slowly? Why do frogs hop? Why are frogs green? Why are colorful frogs poisonous? Why do frogs inflate their throats? What some of the biggest threats are to amphibians and reptiles? We head out to the pond to get answers from some herpetologists! We also get a preview of the new Earth Rangers podcast!

But Why explores the Big Bang, earth, stars and black holes in this call-in episode that aired live on Vermont Public Radio. Astronomer John O'Meara tackles the big bang, the origins of the universe and how we know humans landed on the moon. Plus, why is the earth round? What is space made out of? How are stars formed? Why do the stars shine so bright? What's beyond space? How long does it take to get to outer space? Will humans ever be able to go to Mars?