As light as a geological hammer

A little bit of magic for a drizzly Monday morning (unless of course it's sunny everywhere but Britain...) comes to you courtesy of NASA.com and features a phenomenon called the equivalence principle. Back in the 16th century, Galileo Galilei rolled spheres made of different materials down a long slope, and showed that even though the spheres were very different, they reached the bottom of the slope at the same time. He concluded that gravity accelerates all objects equally regardless of their masses or the materials from which they are made. This 36 year old video shows astronaut David Scott, demonstrating just that, by standing on the moon and dropping a heavy geological hammer and a light falcon feather. Both items hit the ground at the same time, reinforcing Galileo's theory.

The experiment shown in the above video isn't necessarily the most accurate scientific demonstration (nor is it brilliant quality, unsurprisingly), but it was the first such demonstration to be done on the moon, and it's very eye-catching. Even though you know the outcome, it's just impossible to make your brain accept that the hammer and the feather will fall at the same rate. And yet they do.

Comments

[Ed Yong]

That's brilliant! Especially because the experimental design sounds like something a bunch of students might come up with at 3 in the morning after one too many beers:

"I know, I'm going to compare the falling speeds of a hammer and a falcon's feather. On the moon!!!"

[Katie]

So true. Awesome.