From The Desk of...The Chief Scientist

"The Constant Eclipse"

Written by Paul Sutter on Monday, 20 March 2017. Posted in From The Desk of...The Chief Scientist

When the total solar eclipse visits the US this August 21st, the whole experience will last about three hours. Here in Columbus the party starts around 1pm, when the disk of the moon begins to cover up the face of the sun. An hour and a half later, at 2:30pm, we will reach maximum coverage. That maximum ends at...2:32pm. It will be another hour and a half until the moon fully exits the sun, but for some that maximum simply isn't enough.

Hence the anonymous question posted on my COSI whiteboard recently. The eclipse is covering the whole country, entering the US on the Oregon coast near the town of Newport and exiting the Atlantic side via Charleston, South Carolina. Any one spot along the path connecting those two cities will experience totality for around two minutes tops.

But what if we could drive - or better yet, fly - along that path, "catching" the totality in Oregon and riding it all the way to South Carolina? How fast would we have to go to really get the greatness of the Great American Eclipse?

Newport goes dark around 10:20am PDT, and Charleston doesn't follow suit until around 2:50pm EDT, so the most you're going to get for this eclipse is an hour and a half. Due to the moon's orbit the eclipse path doesn't take a direct line between the two cities, but we can take the great circle distance of 2,500 miles as good enough approximation, leading to a speed of 1,600 mph.

That's twice the speed of sound.

"ELI5: Angular Momentum"

Written by Paul Sutter on Monday, 13 March 2017. Posted in From The Desk of...The Chief Scientist

Jarod Smith, a member of the COSI on Wheels team, asked me for help in crafting a quick-and-easy way to explain conservation of angular momentum to young kids, and more importantly sometimes to their parents.

The topic comes up in a fun and simple demo. Sit on a chair that can rotate, and hold a spinning bicycle wheel in your hands. Flip the wheel over and presto-chango you start spinning in your chair. Magic! I mean, science!

I like to think of momentum as the amount of "oomph" an object has - how much it can pack a punch if it were to hit you. A small object (like a bullet) traveling fast enough can hurt, and a big object (like a truck) can be a pain pretty much no matter how fast it's going.

Angular momentum is then oomph going in a circle. It's conserved, which means the total amount of oomph must be the same.

For very young kids, I just refer to it as spin. The bicycle wheel in your hands is spinning really fast in one direction. That's the total amount of spin that you+wheel can have. When you flip the wheel over, you're taking away the spin in that direction, so some has to be added: you yourself start spinning to compensate.

Ultimately, while we can explain what's going on as best we can, I think in some cases it's sufficient to let the demo do the talking. Kids are developing an intuitive sense of angular momentum conservation, and that's something we can build on when they're older.

"The Great American Eclipse"

Written by Paul Sutter on Monday, 06 March 2017. Posted in From The Desk of...The Chief Scientist

Save the date: on the afternoon of Monday, August 21st, the moon will cover the face of the sun, the day will turn to night, and it's time to party!

A total solar eclipse is coming to the US, and the whole nation will get to enjoy it. Something like 95% of the population will be within range of at least 3/4 totality, including Columbus. In our city we'll get between 85-90%, so at 2:30 in the afternoon the sun will just be a thin sliver in the sky. As I type this memo, we're putting together a plan involving COSI and community partners like OSU's Department of Astronomy to make sure as many people as possible get to safely enjoy nature's spectacle.

But I won't be in Columbus on the 21st. I'll be in Nashville. The line of totality - where the sun is 100% covered by the moon and the corona becomes visible - stretches from the Oregon coast, over the Rockies via the Grand Teton National Park, through the great plains, across the Appalachians, and out through South Carolina. And Nashville is the only major city along that path.

I'll be leading a bus trip to see the total eclipse, then we'll take in the sights and sounds of Music City for a few more days. And I'd love for you to join me! We're infusing the trip with all sorts of fun COSI activities, and I'll be there during and after the eclipse to answer your burning (ha!) questions about the sun. COSI team members are more than welcome to join the fun, and you can check out cosi.org/adults for more info.

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