| helium balloon | 2.90 | Fully inflated helium balloons. | ||
| helium gas | 0.99 | This provided valuable volume to be filled with buoyant helium gas. | ||
| helium atom | 0.72 | Singly ionized helium atoms should be detectable. | ||
| helium nucleus | 0.46 | This yields helium nuclei and tremendous amounts of energy. |