Helium is a chemical element with the symbol He and atomic number 2.
Helium is a colorless, tasteless and odorless gas.
Helium is the second most common element in the Universe (after hydrogen), making up around 24% of its mass.
Helium is part of a group of chemical elements called noble gases, the other five that occur naturally are neon, argon, krypton, xenon and radon. Under normal conditions they share similar properties, including being less likely to participate in chemical reactions due to their outer shell of electrons being full. Helium is the second least reactive element after neon.
French and English astronomers Pierre Janssen and Norman Lockyer are jointly credited with discovering helium after spectral analysis of sunlight following a solar eclipse in 1868.
The word helium comes from the Greek word meaning sun (helios). It was named by Lockyer and English chemist Edward Frankland.
The USA is the world’s largest supplier of helium, with many reserves found in large natural gas fields.
The rate at which helium is currently being used by humans is much faster than the rate at which the reserves are being replenished. New technologies for obtaining or recycling helium are one way for gas companies to help slow this problem.
Because helium is lighter than air it is commonly used to fill airships, blimps and balloons. As it doesn’t burn or react with other chemicals, helium is relatively safe to use for this purpose.
While hydrogen is 7% more buoyant than helium it has a much higher fire risk.
You might notice the helium balloon you got from the amusement park slowly falling to the ground after a few days, this happens as the helium gradually leaks from the balloon.
Helium has a lifting force of around one gram per liter. A balloon that holds 10 liters of helium should therefore lift an object weighing 10 grams. Unfortunately you’ll need around 5000 of these balloons if you weigh around 50kgs and want to get off the ground.
The balloon boy hoax from October 15, 2009 led people to believe that a six year old boy had floated away in a home made helium balloon when in fact he was hiding at his house the whole time.
Because helium is less dense than normal air, when inhaled from a source such as a helium balloon it briefly changes the sound of a person’s voice, making it much sound much higher. However, breathing in too much helium can be very dangerous, potentially choking people due to a lack of oxygen.
Helium can be in a liquid and even solid state but they can only occur at temperatures near absolute zero.
Liquid helium is used to cool metals for superconductivity use. The European Organization for Nuclear Research’s (CERN) Large Hadron Collider uses liquid helium to maintain an extremely low temperature.
- Helium is often used in space programs, displacing fuel in storage tanks and having other rocket fuel applications.