Astronauts perform so many out-of-this-world experiments on the International Space Station (ISS). They use a specially-built X-ray telescope to study distant dead stars, collect particles from outer space, and grow crystals that help make new medicines. But they also try experiments that are so simple they could be done with materials you have at home—the only difference is that their home is in microgravity.
Microgravity is what makes living aboard the ISS so unique. This phenomenon is often referred to as “zero gravity,” which is actually a misnomer. Gravity is definitely still present and affecting the space station—in fact, it’s the reason the station stays in orbit around Earth! The ISS’s orbit, however, makes it seem like astronauts aren’t subject to gravity while aboard, where they float about in weightlessness and have to use specialized cups to keep the liquid contents from drifting out.
This difference in gravity on the ISS affects just about everything you can think of: how the human body works, how liquids move, how plants grow, how food cooks. The ISS is naturally, then, an excellent place to test out the laws of physics and the limits of biology, seeing what’s different in outer space.
Charged water particles orbit a knitting needle, showing electrostatic processes in space. Credit: NASASome experiments bring common Earth materials to the station to see how we can adapt to life up there. For example, just like you can grow plants in your garden, NASA astronauts tend to a luggage-sized planter attempting to grow food so they can have fresh veggies in space. The biggest difference? Your backyard plants can use sunshine, but space plants need specialized LEDs to make sure they get the right kind of light to survive and thrive. Astronauts even got to eat a salad from lettuce they grew—and as any home gardener knows, there’s nothing more satisfying than eating the fruits of your labor!
On the ISS, astronauts like Don Pettit (who recently traveled to space again) sometimes even pull together experiments in their free time using everyday materials from their personal kits. These experiments sometimes compare processes we’re used to seeing happen on Earth, like making ice cubes in a freezer, but without the typical Earth gravity. Next time you go to your ice tray, take a look for little white bubbles—those don’t form on the ISS, as Pettit found out in one of his tests.
He also threw together salt, sugar, and coffee in a bag and shook it all together. At home, that’ll just give you a strange seasoning mix, but in space, the little grains clumped together in a way that actually simulates one of the earliest steps of planet formation (how tiny bits of material clump together into bigger chunks, which can then clump together more and more until they become planets).
One of his experiments you really truly can do at home—astrophotography—just with a very different vantage point. Astronauts like Pettit often bring aboard cameras to capture photos of Earth from afar, which can actually be useful for understanding the climate patterns and other happenings of our home world. You might not be able to see the curvature of the Earth in your backyard astrophotography, but you can still see some incredible sights with the right gear.