Here are a number of good science podcasts for kids.
Brains On! Science Podcast for Kids
https://www.stitcher.com/podcast/american-public-media/brains-on
But Why: A Podcast For Curious Kids
http://digital.vpr.net/programs/why-podcast-curious-kids#stream/0
The Show About Science
https://soundcloud.com/the-show-about-science
Stuff You Should Know
https://www.stuffyoushouldknow.com/
Tumble: A Science Podcast for Kids
http://www.sciencepodcastforkids.com/
Wow in the World
https://tinkercast.com/shows/wow-in-the-world/
There are many terrific video channels for kids (and adults!) who want to improve their science knowledge. Here are a few of my favorites.
BBC Earth
https://www.youtube.com/user/BBCEarth
Crash Course Kids
https://www.youtube.com/user/crashcoursekids
MinuteEarth
https://www.youtube.com/user/minuteearth
Peekaboo Kids - Dr. Binocs
https://www.youtube.com/user/Peekaboo
Scholastic Study Jams - Science
http://studyjams.scholastic.com/studyjams/jams/science/index.htm
Science! with the Amoeba Sisters
https://www.youtube.com/user/AmoebaSisters
SciShow Kids
https://www.youtube.com/user/scishowkids