Because the hydrogen molecule is very small, it can easily diffuse through many materials, so that the balloon will deflate quickly.

But the balloon of good fortune that Mr. Hof and his employees have enjoyed may soon deflate.

By the next morning the balloon had deflated again, and the exasperated crew gave up.

So a balloon will slowly deflate, lose all of its helium content.

A boy in the audience pulls the tail of a kerchief from a balloon, but the balloon does not deflate.

We all know how fast life's balloons can deflate; mothers can do that in their sleep.

He and Sawn approached, weapons pointed forward, as the balloons slowly deflated.

The pilot, Robert A. Mock, was killed Saturday when his balloon deflated at 3,000 feet as thousands of spectators watched.

The balloon quickly deflates and falls to the ground, to be recovered and disposed of (balloons are single use).

The balloon was deflating fast and the speed of his fall increased.