Astronauts who’ve spent long periods of time in space have found that once back on Earth, they’re weak and may even have a hard time standing up. What’s the trouble?
Vinegar is an acid, a substance that tastes sour and neutralizes bases. In this activity, the vinegar reacts chemically with a substance in the bone called calcium. Calcium is an important mineral in the body that makes bones strong. The vinegar dissolves the calcium in the bones, so the bones are no longer strong and are thereby bendable.
Another way that your bones can lose calcium is through lack of exercise. That’s why some astronauts may come back to Earth with weakened bones and why they now have treadmills and other exercise machines on the International Space Station.