Student Challenge: Understanding Weightlessness – You Want Me to Take a Bathroom Scale Where?

As I write, the clock is ticking down to the currently scheduled launch of SpaceX’s Falcon rocket, which will ferry Dragon and the Aquarius payload of SSEP Mission 1 experiments to the International Space Station. We’re now just 36 days away from the earliest possible launch date … which means I’ve got plenty of time to get ready for my way cool experiment.

I’ve heard a lot about this weightlessness stuff, and astronauts having a great time floating around. So I wanted to find out first hand what’s going on up there. Since they don’t have a spare seat on Falcon (at least not yet), I looked far and wide to find an amazingly tall mountain whose peak rises to the Space Station’s orbital altitude. Station orbits the Earth about 210 miles (340 km) above sea level, and, by the way, crew and station are zipping along at 4.5 MILES PER SECOND (7 km/sec) relative to you sitting there at your computer.

It took some Googling, but I found it! See my mountain in the picture? Mt. Everest is only 5.5 miles (8.8 km) high. MY mountain (Jeff’s Peak) is 210 miles (340 km) high. I found it south of the Land of Make-Believe, down a not too well traveled path. Still, you’d think someone would have noticed it.

So while waiting for Falcon to launch, I’m going to take the time to climb my mountain, and in my hand is my trusty bathroom scale, spring-loaded and guaranteed to be accurate at any altitude. I’ll camp out at the top and I’ll wait until Space Station flies right by my mountain, so I can look in the windows and see if those lucky astronauts are weightless and floating around.

Here now the challenge—
As soon as I confirm they’re weightless in the Space Station, I’ll look down at my bathroom scale to see my weight. If I weigh say 150 lbs (68 kg) when I’m standing on my scale in my bathroom at home, what will I weigh on top of my mountain?

Hint: I’m not asking you to actually calculate my weight. I’ll do that in the Solution to the Challenge. Your assignment—if you decide to accept it—is to guess what you think I’ll weigh and why. Hmmmm, lots of possibilities.

Post your guesses below, and remember to include why you think your guess is correct. Students of ALL ages are welcome to post a guess.

I’ll even give you a week to noodle on this in class, and at home with your parents, and then post your guesses. I’ll post the answer next Sunday, April 1, 2012. See you then, and good luck noodling!

SOLUTION: The solution to the challenge is now posted HERE. But wait! Before you jump to the solution, make sure you’ve thought about the possibilities first!