Exploring the Elements: Helium

for the past few months I've been collecting as many of the chemical elements as I can and in this series I'll be showing you my collection and explaining the science behind these building blocks of the universe [Music] next up is element number two helium foreign of course we're all familiar with helium balloons from parties of Parade floats [Music] and that time in 1986 when a fundraiser in Cleveland released 1.5 million balloons and they all flew over Lake Erie accidentally preventing Rescue helicopters from saving some dren fishermen and they died um that actually happened yeah helium is less dense than air so it floats much like hydrogen does um like hydrogen however helium isn't flammable and in fact won't react with other chemicals under normal conditions this makes helium a bit of a safer choice for say a blimp or a zeppelin something you don't want burning helium is part of the group in the periodic table called noble gases noble gases like helium have a full shell of electrons and therefore don't tend to form bonds with other atoms in order to have a sample of helium that lasts longer than a balloon I've got some helium here that's contained in a glass ampule there's really not much to see right now but like we saw with the hydrogen last time an ampule of low pressure gas can actually glow in a strong electromagnetic field my helium sample actually glows quite a bit brighter than my hydrogen sample and using a diffraction grating shows the wavelengths even more clearly in fact this distinctive spectrum is what led to helium's Discovery in 1868 astronomers Jules Jansen and Norman lockyer viewed a solar eclipse through a prism and saw a distinctive yellow line which was later found to be from a previously unknown element scientists named this new element helium after Helios the Greek word for the Sun it's a fitting name as the sun itself actually creates helium via Fusion deep down at the center of the sun's core the pressure is so strong the atoms of hydrogen are literally fused together to form helium [Music] this Fusion releases energy trillions of these fusions occur every second and create the light and heat that we feel even millions of kilometers away [Music] helium is the second most abundant element in the universe after hydrogen making up almost 23 percent of all known matter however here on Earth helium is much more rare because it is both inert and very light helium gas tends to float up to the top of the atmosphere we're just blown away into space by solar winds [Music] so where does all the helium on Earth come from well it turns out there's more than one way to create helium helium can be created by fusing smaller atoms together or by breaking larger ones apart [Music] inside some common household smoke detectors is a device known as an ionization chamber containing a small amount of radioactive material which ionizes the air and makes it possible to detect smoke particles at the center of this little metal button is a piece of gold foil impregnated with a microscopic amount of the radioactive synthetic isotope americium-241 41 Haze into neptunium 237 by emitting an alpha particle consisting of two protons and two neutrons look familiar that's right an alpha particle is just the nucleus of a helium atom these alpha particles are highly charged and dangerously ionizing however they don't travel very far and are easily blocked by the plastic shell of the smoke detector while these particles are far too small to see we can detect them with a special attachment for the geiger counter foreign [Music] [Music] in a container full of super saturated alcohol vapor actually watch as the alpha particles ionize the air oh my God [Music] [Music] [Music] thank you [Music] [Music] while americium is a good example of an alpha radiation emitter natural elements like thorium and uranium buried in rocks deep underground also undergo alpha decay creating helium gas over millions of years the helium slowly builds up in pockets of natural gas which is where we get most of our helium from today in other words the helium in this party balloon came from the radioactive decay of heavy elements deep inside the Earth this also means that helium is a non-renewable resource and we might just end up running out of it which is a shame since helium is useful for a lot more things than just party balloons helium has the lowest freezing point of any element and liquid helium is essential for cryogenics like superconductors and MRI machines helium boils at 4.2 degrees Kelvin under conditions of atmospheric pressure helium is a remarkable substance it has two different and easily distinguishable liquid phases a warmer and a colder one but it is helium-2 the colder phase which is truly different because of this it is called the superfluid the viscosity of helium-2 in this experiment is so small that it has not been possible to find a value for it [Music] despite helium's abundance throughout the Universe scarcity on earth makes helium a precious and important element [Music] [Music] thank you [Music] foreign [Music]

Channel: Exploring our World with Science!

Views: 17,323

Keywords: helium, periodic table of elements, education, science, chemistry, balloons, alpha radiation, superfluid

Id: uxwpUDLUilU

Length: 9min 53sec (593 seconds)

Published: Mon Jul 10 2023