Gallium (beating heart) - Periodic Table of Videos

Summary

In 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

00:00

🔬 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.

05:03

🌌 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.

Keywords

💡Gallium

Gallium is a soft, silvery metal with a low melting point, which is why it can be melted in the hand as demonstrated in the script. It is used in the video to illustrate the 'gallium beating heart' experiment. Gallium is also important in the production of semiconductors and is used in medical thermometers as a non-toxic alternative to mercury.

💡Sulphuric acid

Sulphuric acid is a strong, corrosive acid used in the experiment to react with molten gallium, forming gallium sulfate. This reaction changes the surface tension of the gallium, causing it to form a ball and exhibit the 'beating heart' effect. The script mentions diluting concentrated sulphuric acid with water, emphasizing safety precautions in handling such chemicals.

💡Surface tension

Surface tension is the property of a liquid that allows it to resist external forces, due to the cohesive nature of its molecules. In the video, the surface tension of gallium changes when it reacts with sulphuric acid, causing it to form a ball. This concept is central to understanding the 'beating heart' phenomenon.

💡Oscillating reaction

An oscillating reaction is a type of chemical reaction that involves periodic changes in the concentration of the reactants. In the context of the video, the 'gallium beating heart' is an example of an oscillating reaction, where the surface tension of gallium changes, causing it to alternate between a flat and a spherical shape.

💡Mendeleev

Dmitri Mendeleev is known for creating the periodic table of elements. The script mentions that he predicted the properties of gallium, which was later discovered and named eka-aluminium by him. This highlights the significance of Mendeleev's work in predicting undiscovered elements based on the periodic law.

💡Amalgam

An amalgam is a mixture of a metal, especially with mercury, that is used in various applications such as dental fillings. In the script, it is mentioned that gallium can form an amalgam with other metals like indium and tin, which is significant in the medical industry due to its non-toxic nature compared to mercury.

💡Dichromate

Dichromate is a strong oxidizing agent used in the experiment to remove gallium sulfate from the surface of the gallium, allowing it to flatten. This is part of the process that creates the 'beating heart' effect by changing the surface tension of the gallium.

💡Compound

A compound is a substance formed when two or more chemical elements are chemically bonded together. The script discusses the creation of a new compound with a bond between uranium and gallium atoms, marking a significant scientific discovery in the field of chemistry.

💡Periodic table

The periodic table is a tabular arrangement of the chemical elements, ordered by their atomic number, electron configuration, and recurring chemical properties. The video script refers to the periodic table in the context of Mendeleev's predictions and the discovery of gallium, as well as the creation of a new gallium-uranium compound.

💡Electron configuration

Electron configuration describes the distribution of electrons in an atom's orbitals. While not explicitly mentioned in the script, the concept is implied when discussing Mendeleev's predictions and the properties of elements, as electron configuration is fundamental to understanding an element's position on the periodic table.

💡Melting point

The melting point is the temperature at which a solid changes into a liquid. The script recounts a story about a bet on the melting point of gallium versus caesium, highlighting the unique properties of gallium and its low melting point, which is a key aspect of the 'gallium beating heart' experiment.

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.