To understand why helium balloons deflate, it helps to first understand why they float. Helium is lighter or less dense than air. What this means is that a balloon filled with helium has … See more

So, helium atoms are very small. The reason helium balloons deflate so quickly is because helium escapes a balloon faster than air can enter it. In fact, helium diffuses through a s… See more

Hydrogen balloons are even lighter than helium balloons. Even though hydrogen gas contains hydrogen molecules (H2), it’s still less dense than monatomic helium (He). The h… See more

A deflated helium balloon still contains helium, so it’s possible to revive it and make it float again. Warm the balloon by placing it in a hot location or gently heating it with a hai… See more