We often think of yawning as something that happens when we're tired but the answer is much more mysterious. Nij and the kids meet Dr Kathleen Maddison at the Centre for Sleep Science for an adventure that starts all the way back in caveman times! 

For more great kids podcasts, download the free ABC listen app (Australia). There you’ll find more kids news podcasts, educational children’s stories and storytelling, podcasts from your favourite characters like Bluey and Hey Duggee and plenty more of the best kids podcasts like Imagine This, Dino Dome and News Time. For all ages from 0–4-year-olds, 5–8-year-olds, 8–10-year-olds, tweens and teens. And you can watch our kids shows on ABC iview and on the ABC Kids and ABC Big Kids channels of YouTube kids.

We all know it’s important to use sunscreen in the hot Australian sun, but what exactly is sunscreen? And how does it work? Nij and the kids are joined by dermatologist Professor Pablo Fernández-Peñas for a slippery, summery and sparkling journey.

It's time to get nosy as we answer: What is snot? What are boogers? How is snot made and why do we have it? Nij and the kids join Associate Professor Kim Murphy on a slimy slip and slide through some giant nostrils.

The grass is wet, but there’s been no rain, and the skies are clear... What explains the dampness covering everything on a cool morning? It's called dew! 

Meteorologist and ABC weather presenter Nate Byrne joins Nij and the kids to explain what exactly dew is, and where it comes from. 

Nij is out of fridge magnets and discovers they can't be replaced by just any piece of metal. What gives magnets their power to pull and push, and how do they stick to things? Nij and the kids get the answer from physicist Dr Cathy Foley, who explains how magnets work and why they're so special.

Nij has nits! But what are nits, and why do they make us itch? Medical entomologist Cameron Webb and the kids comb through Nij's head for a close-up look.

Imagine This host Dr Nij joins Costa and the Gardening Australia Junior crew to find out why worms are so good for the garden.

To celebrate Science Week, we're heading back to space with Dr Kirsten Banks to learn about something very powerful and mysterious.... Black holes! 

We recommend listening to How are stars made? first before listening to this bonus episode. 

Twinkle twinkle, little star, how I wonder what you are…. No, really – what are stars made of and how did they get all the way up there in the sky? Let’s find out more with astrophysicist, Dr Kirsten Banks! Get ready to blast off in 5, 4, 3, 2 1!

If you don’t drink water, urine trouble! It’s a wee-lly important thing to stay healthy. So how do our bodies turn this clear water into yellow pee? Nij and the kids meet Dr Sradha Kotwal to follow the journey through our bodies from water to wee!

We see glass every day, we see right through it! It’s in our windows and our fridges, our cars and our devices… But how do you make all this hard, clear stuff? Pack your bags, we’re off to Ancient Egypt to find the answers!