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Bridges vs. Tunnels

Right: A metro drives through a tunnel on December 18, 2012 in Paris. (JOEL SAGET/AFP/Getty Images) Left: An aerial view of the Golden Gate Bridge on September 7, 2013 in San Francisco, California. (Ezra Shaw/Getty Images)
Right: A metro drives through a tunnel on December 18, 2012 in Paris. (JOEL SAGET/AFP/Getty Images) Left: An aerial view of the Golden Gate Bridge on September 7, 2013 in San Francisco, California. (Ezra Shaw/Getty Images)

We’ve gotten a lot of questions about bridges and tunnels: How do bridges stay up? How are tunnels built? How do they build bridges over water? How do they put tunnels underwater? To answer these questions we’re staging a little friendly competition: bridges vs. tunnels!

Thunder, lightning and tornadoes: Where do they come from?

LAS VEGAS, NV - JULY 06:  Lightning strikes during a thunderstorm on July 6, 2015 in Las Vegas, Nevada. The monsoon storm dropped heavy rain and hail in parts of the valley causing street flooding and power outages.  (Ethan Miller | Getty Images)
LAS VEGAS, NV - JULY 06: Lightning strikes during a thunderstorm on July 6, 2015 in Las Vegas, Nevada. The monsoon storm dropped heavy rain and hail in parts of the valley causing street flooding and power outages. (Ethan Miller | Getty Images)

There are some basic ingredients to make thunderstorms and tornadoes. We’ll find out what they are – and how to observe these powerful and amazing storms safely.

Mission to Pluto!

A rendering of Pluto and Charon. (Courtesy of NASA)
A rendering of Pluto and Charon. (Courtesy of NASA)

We talk to Dr. Alan Stern, the leader of NASA’s mission to Pluto – New Horizons. He’s been working on the mission for over 20 years and he’s excited to see the surprises that New Horizons will be sending back. Plus: Take a quiz to test your New Horizons knowledge!

Trees: From seed to shining seed

A freshly planted white cedar seedling sat in the ground Wednesday, May 20, 2015 near Finland, Minn. (Derek Montgomery for MPR News)
A freshly planted white cedar seedling sat in the ground Wednesday, May 20, 2015 near Finland, Minn. (Derek Montgomery for MPR News)

How do trees make oxygen? How do they grow? How do evergreens stay green all year? Why do tree leaves change color? How long can trees live? We’re branching out to tackle all these questions in this episode.

How does GPS know where you are?

GPS III satellite (Courtesy of GPS.gov).
GPS III satellite (Courtesy of GPS.gov).

Without GPS, we’d be lost. Literally. Thanks to these radio transmissions from space though, we’re able to pinpoint our location and find our way home. Join us as we learn all about satellites, how the robot voice of GPS is created and how atomic clocks hold it all together.

How and why do jellyfish sting?

Jellyfish! (Sanden Totten | KPCC)
Jellyfish! (Sanden Totten | KPCC)

All jellyfish sting – but not all jellyfish sting people. In this episode, we learn about how jellyfish sting and how they eat. Plus: stro-bi-la-tion (how jellyfish grow up).