①On Earth, when you go to the bathroom, gravity (重力) helps the pee (小便) and poop (大便) go down into the toilet and stay there. But in space, things float (漂浮) around. When the Space Station goes around the Earth, it feels like there is no gravity on board.

②“In space, if you had a common toilet, the water would just float around and finally float out,” says NASA astronaut Randy Bresnik. It’s too awful!

③In space toilets, gentle vacuums (真空装置) do the work of gravity. Flowing air sucks (吸) everything into the toilet and holds it there.

④To pee, astronauts use a simple funnel (漏斗) connected to a soft pipe. There are different tops for men and women. Astronauts poop into a metal toilet with a very small opening, the size of a baseball. Vacuum helps to move everything along.

⑤Instead of flushing (冲水), astronaut s use throwaway bags in the toilet. When they finish, they close the bag and push it through a hole into a waste bin. The Space Station has its own water treatment machine, where dirty water, including pee, is cleaned and recycled. Bags of poop go out with the rubbish. They burn up with the rest of the rubbish when they hit Earth’s atmosphere (大气层).

⑥Because going to the bathroom is quite different in space, astronauts have to learn how to work the space toilets and how to sit correctly over the small hole. They practice on Earth to get better at it. Training helps to make these daily tasks easier, leaving more time for science.

⑦But some things can only be learned in space. “When you go to the bathroom in space, you have to use your elbows (肘部) and your feet to hold yourself in the right position because there’s no gravity,” says Scott Wenstein, who trains astronauts. As he notes, “On Earth, it’s easy to eat, go to the bathroom, and sleep because gravity helps out. In space those basic things take a little bit more time and effort.”

Do you know where the hottest place in the world is? It’s Dallol, in Ethiopia. It can get as hot as 51°C. Water is hard to find, so nobody lives in Dallol. It has no stores, farmland or roads. Many people travel to Dallol from the closest villages to work at the salt mine (盐矿）. They sell salt to get money. Everybody works long days under burning sun. When they finish their work, they travel by camel （骆驼）back to their villages.

Oymyakon, Russia is the coldest town in the world. Once, the temperature was -71°C. Before the 1930s, very few people lived in Oymyakon. Then someone found gold （金子）, so more and more people went to work there. Today, about 500 people live there. There’s a food store. It sells bread, milk, meat and so on. However, there are no movie theaters or phone service.

Oymyakon may be cold, but people there are warm and friendly. The neighbors（邻居）care about each other.

Our life will be different from now with robots appearing in our home. So what will the future be like? Here are some students’ ideas.