Gallium (beating heart) - Periodic Table of Videos
Summary
TLDRIn this intriguing video, the presenter demonstrates the 'gallium beating heart' experiment, where molten gallium reacts with dilute sulfuric acid, forming gallium sulfate and causing oscillating surface tension changes. The gallium appears to 'beat' like a heart. The video also discusses gallium's melting point, its applications in the electronics industry and medical thermometers, and the recent discovery of a gallium-uranium bond, highlighting the excitement of pioneering new chemical compounds.
Takeaways
- 🔬 The 'gallium beating heart' experiment involves reacting molten gallium with sulfuric acid to demonstrate changes in surface tension.
- 🏵️ Gallium has important applications, contrary to an earlier statement in a video, including in semiconductors and medical thermometers.
- 🤲 The presenter attempts to melt gallium in their hand, highlighting its low melting point compared to other metals.
- 💡 Mendeleev predicted the properties of gallium, which was later discovered and named for its discovery in France.
- 🧪 The experiment shows gallium's surface tension changing from flat to a rounded ball due to the formation of gallium sulfate.
- 🌡️ Gallium forms amalgams with other metals like indium and tin, which are used in medical thermometers as a safer alternative to mercury.
- 🧴 Diluting concentrated sulfuric acid with water is a crucial step in the experiment, done carefully to avoid a violent exothermic reaction.
- 🔄 The 'beating heart' effect is achieved by alternating the surface tension of gallium with the use of dichromate to remove the sulfate.
- 📚 The script mentions a recent scientific breakthrough at Nottingham involving a new compound with a uranium-gallium bond.
- 🎢 The excitement of being the first to create a new compound is likened to a rollercoaster of emotions in the scientific community.
- 🌐 The new uranium-gallium bond represents a significant addition to the periodic table, marking a first-time discovery.
Q & A
What is the 'gallium beating heart' experiment?
-The 'gallium beating heart' experiment involves taking molten gallium and submerging it under a layer of dilute sulfuric acid. The acid reacts with the gallium to form gallium sulfate, which changes the surface tension and causes the gallium to form a ball that oscillates, resembling a beating heart.
Why was the narrator attempting to melt gallium in their hand?
-The narrator was attempting to demonstrate the low melting point of gallium, which can be melted by the heat from a human hand, showcasing its unique physical properties.
What is the significance of the bet the narrator mentioned about gallium and caesium?
-The bet highlighted a misunderstanding about the melting points of gallium and caesium. The narrator believed gallium had a higher melting point than caesium, which was incorrect. This anecdote emphasizes the importance of accurate scientific knowledge.
What are some applications of gallium mentioned in the script?
-Gallium is used in the production of gallium salts for various important applications. It is also particularly important in the creation of new-generation semiconductors used in the electronics industry, and as an amalgam in medical thermometers due to its lower toxicity compared to mercury.
Why is the narrator careful to add acid to water and not the other way around when diluting sulfuric acid?
-When diluting concentrated sulfuric acid, it is important to add the acid to water to prevent an exothermic reaction that could cause the mixture to splash or spray, potentially causing injury.
What is the role of dichromate in the 'gallium beating heart' experiment?
-Dichromate acts as an oxidant in the experiment. It is used to remove the gallium sulfate from the surface of the gallium, allowing the gallium to flatten. When the right amount of dichromate is added, it can induce the oscillating 'beating heart' effect.
Why was Mendeleev able to predict the properties of gallium before it was discovered?
-Mendeleev was able to predict the properties of gallium based on his understanding of the periodic table and the trends among elements. He named the predicted element eka-aluminium, and it was discovered shortly after, confirming his predictions.
What is the significance of the new compound formed by Steve Liddle involving uranium and gallium?
-The new compound is significant because it represents the first time a bond between uranium and gallium atoms has been observed. This discovery expands our understanding of chemical bonding and the potential for new materials.
What does the narrator mean by 'being a chemist is like being on a rollercoaster'?
-The narrator is expressing the highs and lows of scientific research. There are challenging days when progress is slow, but also exhilarating moments of discovery and innovation, such as being the first to create a new compound.
What is the significance of the 'new union' mentioned at the end of the script?
-The 'new union' refers to the formation of a new chemical bond between uranium and gallium atoms. This discovery is a significant contribution to the field of chemistry and represents a unique achievement for the researchers at Nottingham.
Outlines
🔬 Gallium Experiment: The Beating Heart
The script introduces an experiment involving molten gallium and its reaction with sulfuric acid to create a 'beating heart' effect due to changes in surface tension. The narrator shares a personal anecdote about a bet on gallium's melting point and discusses its applications in electronics and medical thermometers. The process of melting gallium with hand heat and preparing dilute sulfuric acid for the experiment is described, culminating in the initial stage of the 'beating heart' as the gallium forms a ball due to increased surface tension from the reaction with the acid.
🌌 Scientific Discovery: Gallium and Uranium Bond
This paragraph delves into the scientific excitement at Nottingham University over the creation of a new compound featuring a bond between uranium and gallium atoms, marking a first in chemistry. The paragraph explains the 'beating heart' effect in more detail, describing how dichromate solution is used to remove gallium sulfate from the surface, causing the gallium to oscillate between a flat and a spherical shape. The discovery of the gallium-uranium bond is likened to a thrilling rollercoaster moment in chemistry, emphasizing the joy of being the first to create something never seen before in the universe.
Mindmap
Keywords
💡Gallium
💡Sulphuric acid
💡Surface tension
💡Oscillating reaction
💡Mendeleev
💡Amalgam
💡Dichromate
💡Compound
💡Periodic table
💡Electron configuration
💡Melting point
Highlights
Experiment to demonstrate the 'gallium beating heart' using molten gallium and sulphuric acid to create an oscillating reaction.
Misunderstanding about gallium's melting point led to a missed bet and potential wealth.
Gallium's importance in the electronics industry, particularly in semiconductors.
Gallium's use in medical thermometers as a less toxic alternative to mercury.
Mendeleev's prediction of gallium's properties before its discovery, highlighting his contribution to the periodic table.
Demonstration of gallium's melting process using body heat.
Formation of an amalgam with gallium, indium, and tin, and its application in thermometers.
Safety precautions when diluting concentrated sulphuric acid with water to prevent exothermic reactions.
Visual demonstration of gallium's surface tension changes upon contact with dilute sulphuric acid.
Use of dichromate to alter gallium's surface properties and induce the 'beating heart' effect.
The historical significance of gallium's naming, derived from the old name for France, Gaul.
Description of the chemical process behind the gallium 'beating heart' experiment.
Excitement over a new gallium-uranium compound created at Nottingham, marking a first in chemistry.
Reflection on the thrill of being the first to create a new chemical compound.
A new bond between uranium and gallium, a significant discovery in the periodic table.
The emotional rollercoaster of being a chemist, from doubt to the joy of discovery.
Transcripts
We are going to try and do an experiment today. It is called
the ‘gallium beating heart’. So it is quite a cool experiment,
you take some molten gallium and then you submerge it or
you put it underneath a layer of sulphuric acid. The sulphuric
acid reacts with the gallium to form gallium sulphate and it
changes the surface tension, so it all pulls up into a ball and
then relaxes and there is this really neat oscillating reaction
where you get sulphate on the surface or no sulphate on the
surface. So you see big changes in surface tension and the
piece of gallium is seen to beat like a heart so we thought we
would try that today with a bit of gallium which I am trying to
melt in my hand right now.
Many years ago, a professor bet me a hundred pounds, when
a hundred pounds was a lot of money, that the melting point
of gallium was lower than that of caesium and I said it was
the other way round, but I was not courageous enough to
take up the bet or now I would be rich.
So this is a small nugget of gallium and as you can see if I
tap it on the hot plate it is real metal so now we are going to
try and melt it, hopefully in my hand.
In my first video about gallium, I said that it was not a very
interesting element with not much, many applications and we
have had emails from people who were outraged. There is
one email from a gentleman in America whose company
makes tonnes of gallium salts that have quite important
applications and of course gallium is particularly important in
new generation of compounds, so-called semi-conductors, that are used in the electronics industry.
So if I stand and hold it for long enough, in theory, the
temperature should come from my hand, the heat should
come from my hand, so it should melt the gallium and then
eventually we should have a small amount of liquid. So
gallium, you can form an amalgam with this material, with all
sorts of different materials like indium and tin. And in fact
indium, tin and gallium is used as the material inside many,
many thermometers which are used in the medical industry
because it is not as toxic as mercury which was traditionally
used. You may have heard of Mendeleev. He was the guy that
sort of conceived or brought together the periodic table and
at the time that he did this at about 1870, gallium hadn’t
been discovered, so he predicted its chemical and physical
properties and he called it eka-aluminium, approximately 5
years after that it was found using a spectroscope. So now
we see it is melted, it looks just like a little ball of mercury
rolling around on my hand. You can see the thick skin that
has developed the surface tension causing it to form such a
beautiful bulb. We are going to take out our molten gallium
and we are going to put it under a layer of dilute sulphuric
acid, about the same strength as battery acid, so now we are
going to make the acid. And to do that we are going to dilute
concentrated sulphuric acid with water. Now it is always
important to remember that when you dilute acid you always
put acid into water because the reaction can be exothermic
and we want to dissipate the heat in the water so that it does
not squirt up on our faces. The water was room temperature,
but if I hold the measuring cylinder here it is actually very
hot, it is maybe 40, 50, 60oC. So now before we do our
experiment we have got to allow it to cool. We do that by
simply running cold water outside the tube.
So this is the gallium that we melted on our hand, now let’s
see what happens when we add the sulphuric acid. Wow, did
you see that?
I did. What happened?
So the shape of the ball or the lump of gallium has changed,
because we’ve changed it surface properties, we’ve
made gallium sulphate on the surface. The surface tension
has got higher and it has pulled up into a nice ball, ok. So
that’s the first step of the beating heart. What we’ve seen is
the gallium which was relaxed flat on the surface has pulled
up really quite sharply and that is the first stage, or the in-
beat of the heart, now we’ve got to make the heart relax. So
what we are going to do is use dichromate. Dichromate is a
fantastic oxidant and we are going to put a small amount of it
in and see what happens.
So gallium, I realise now is named after France. It was
discovered by a Frenchman and its name comes from the old
name for France, Gaul.
So what we are doing in this experiment, we are changing the
surface tension of the gallium, so these are the forces that
hold the liquid into a ball or allow it to wet and flatten on the
surface. So when the gallium is naked, ok? It’s actually quite
flat and it wets the surface. But when we put it under
sulphuric acid we form gallium sulphate on the surface, this
increases the surface tension and then pulls the gallium so it
is in a nice proud ball. What we then do is we dribble a small
amount of dichromate solution in, which removes the
sulphate from the surface and allows the gallium to go flat,
and if we add the required amount of dichromate to the
amount of acid then we can get the ball to flatten and come
back up, flatten and come back up, so it looks like a beating
heart.
At the moment we are really quite excited at Nottingham
because Steve Liddle, my periodic videos colleague, has made
a new compound in which he has got an atom of uranium to
bond to an atom of gallium and this is exciting because this is
the first time that chemists have ever seen a bond between
these two atoms.
It sort of turns a terracottery colour, it is really a deep orangey
brown, it is a bit like brick dust actually.
Of course they are not naked uranium and naked gallium but
each of them have other things bonded to them but it is the
first time that anybody has seen a gallium-uranium bond.
It was one of those great moments you know, being a
chemist is like being on a rollercoaster, you have some days
when you wonder why am I doing this? And you have
fantastic days where you totally remember why you are doing
this. Because it is to be the first, to be the first person who
has ever made this particular, you know filling the gap,
whatever it is. It is a real thrill when you are the first person
to make a compound that does not exist out in the galaxy
and space, it has never existed on our planet before but now
we have made it for the first time. That’s a really good thing
to do
We are really very excited! A new union has been formed
within the periodic table and it has been done here at
Nottingham.
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