Armagh Planetarium’s great balloon race has ended.  The results are in and they have been checked and verified.  There were balloon reports on the Cathedral Road, the Battleford Road and a balloon was found on the Pearse Og Football field in Armagh.  We even had an email that one was found in Caledon in County Tyrone, but the winner of the great balloon race was…..(drum roll followed by dramatic long pause) ……… Helen Seedhouse from Hillsborough!  Helen’s balloon was found by Rosalie Lechner in Bavaria, Germany.Yes,  that’s right a helium balloon left Armagh Planetarium and was found in Germany!  That means it travelled almost 900 miles (1450 km)!  That is pretty cool, but how did it travel that distance?


The balloons were launched behind the handing over of the Olympic Torch outside the Planetarium building (Image credit:Sinead McNicholl)

Helium is a gas which is lighter than air.  The atomic number of helium is two, making it the second lightest element, only hydrogen is lighter.  It is identified on the periodic table with the symbol He, and it is the least reactive of the noble gases.  The extreme stability of helium makes it a popular choice for a range of uses where unstable materials are being handled, or where the use of other elements might be dangerous such as hydrogen which is highly flammable and a small spark can cause an explosion.

image of Balloons in net

Balloons ready to take off to the skies (Image Credit:Sinead McNicholl)


Helium was discovered in 1868 by French astronomer Jules Janssen and Norman Lockyer who observed a strange yellow band of light during a solar eclipse.  The band of light did not correlate with any known element, and the observers realised that they had identified a new gas.  They named their discovery “helium” after the Greek Helios which means “Sun.”

So, that’s the history bit over!  How does Helium work in a balloon?

The reason that the balloon floats up in the air is because, as we have discovered, helium is lighter than air.  Think of it a bit like a boat floating on the water or marshmallows on the top of your hot chocolate.  The balloon is pushing air out of the way that weighs more than the weight of the helium and the balloon together.  This means that the heavier air comes in underneath the balloon and the balloon is pushed up in the air.  This results in the balloon moving up in the air and this process will carry on going until the helium filled balloon reaches a point or an altitude where the air is the same density as the helium and balloon together.  That is the maximum height which defines how high the balloon can go.


image of ascending balloons

Balloons flying up into the air….Can you spot the one that travelled to Germany?(Image Credit:Sinead McNicholl)

As you get higher up, the air pressure reduces so the balloon is going to try and expand.  Depending on how heavy the balloon is and how quickly it will lose its helium (it can get through the gaps in the rubber polymers quite easily) the balloon will keep on travelling upwards until either it gets heavy enough that it can’t get any higher or the difference in pressure inside and outside is enough that it will explode.Research suggests latex balloons as used in our race rise for about 90 minutes until they reach an altitude of about 5 miles (8km), a height known to mountaineers by the omnious name the “Death Zone”.At this height the temperature is about -40 C and the atmospheric pressure is about half that at sea level.The lower pressure outside allows the balloon to swell, and the cold makes the latex brittle.Sooner or later, each balloon will ruptre and fall to Earth (sadly most will never be found).

Could helium lift a person?

Helium has a lifting force of about one gram per litre because helium atoms weigh less than the oxygen and nitrogen atoms in the air. This means if you take a one-litre bottle and fill it with helium, it will weigh about one gram less than the same bottle would filled with air. One gram of lifting power sounds very unimpressive (especially when you think that a penny weighs just 3 grams).

So could some helium filled balloons lift me?  Well, if one litre of helium can lift about one gram, and if you weigh 100 pounds, then you are going to need about 45 300 litres of helium to lift yourself off the ground and there are 453 grams in a pound. So now the question is, how many balloons does it take to hold 45 300 litres of helium?

A normal balloon is normally about one foot in diameter and holds about 14 litres of helium.  Thus it can lift 14 grams or thereabouts. So, you would need 3,235 balloons (45300 ÷ 14 = 3235) to lift a 100 lb person. That’s a lot of balloons. Plus you would need to add some more balloons to compensate for the weight of the 3235 balloons and the string used. But what if we were to get a bigger balloon!  Let’s look at a weather balloon that is 4 feet in diameter. A balloon like that can hold about 1000 litres of helium so it would take around 46 of those balloons to make it off the ground.  Basically the bigger the balloon, the more it can lift.

Image of Above atmosphere

Taken from a weather balloon 100,000ft (more than 30km) in the air.(Image credit:via


In the Pixar film “Up”, Carl Fredricksen strapped hundreds of bright balloons to his house to transport it from the U.S. to South America.  Yes, it is a cartoon, but in reality Jonathan Trappe did something similar, albeit not moving his house!  Trappe became the first person to cross the Channel with only helium keeping him afloat!  The 22-mile journey took a little more than four hours to complete in which he sat in a wicker chair beneath 54 helium filled balloons.  On board he had a sat nav, radio equipment, emergency beacons and oxygen masks.

Image from movie Up

In the film “Up”, helium balloons are used to lift a house (Image credit:Disney/Pixar)


The dare-devil reached a height of 7500ft and travelled up to speeds of 25mph, cutting away balloons to slow him down and descent.  He landed in Dunkirk in Northern France, and had to explain his unexpected arrival to French gendarmes!  But stunts like this can go wrong and helium should not be used without precaution!  In 2008 a Brazilian priest Adelir Antonio de Carli unsuccessfully flew using a chair and 1,000 helium balloons.  He did not check the weather forecast before setting off on his mission and unfortunately got caught in a storm and was last heard on the radio approaching the water after flying off the coast.  This stunt ended in complete disaster with the priest losing his life.

Another very successful stunt was when two Canadian teenagers successfully sent a Legoman up on a helium balloon to the edge of our atmosphere.  The Legoman travelled 80 000ft up into the air with the entire journey being captured on video.  The cost of this experiment to the two seventeen year-old Canadian students Mathew Ho and Asad Muhammad was a mere £254!

And 18-year-old Raul Oaida even made a tribute to the space shuttle by sending up a Lego figure of the shuttle to space.

I don’t know if I would like to try and float off on a giant helium balloon, but at the Planetarium we may try out the helium balloon experiment in the near future and hold another Great Balloon Race.  But Helen and Rosalie have set the standard, so we hope the next balloon launch will produce one that travels further than the 900miles the last one did to Bavaria in Germany.  The sky is the limit!


To view an interactive map of where the balloons travelled please click on this link .

(Article by Sinead McNicholl, Education Support Officer)



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