Whether we are aware of it or not, we currently have more computing power in our cell phone than NASA used to put a man on the moon, and thanks to our "smart" phones we can surf the internet at high speed, enjoy music and videos with great quality, and communicate with our family and friends through applications that made text messaging almost obsolete.
Well, this would not be possible without chemistry, because every time we use our smart phone, a great amount of chemical elements come into action, so many, that without counting the radioactive elements, we hold almost 70% of the elements of the periodic table in our hands.
A large number of elements make it possible for our smart phones to work the way they do. Source: image edited by @emiliomoron, original from pixabay.com.
And where are all these elements?
Surely with your phone in hand you are already thinking about the substances that can be part of some components of the phone, such as plastic, metal and glass. But we are not going to be so generic in this post, we are going to go deeper than that, and you will see that it gets interesting. Although the real composition of some components is unknown, since they are kept under the dark mantle of patents, it is possible to find enough information about the chemical composition of some of the main parts.
According to some publications, we can find approximately 60 to 70 elements of the 83 stable ones in the periodic table. With the particularity that there is also a great amount of the elements of the lanthanide group, the two rows that we find floating in the lower part of the table.
Only one iphone contains eight rare earth metals, these are: lanthanum, cerium, praseodymium, neodymium, europium, gadolinium, terbium, dysprosium. Thanks to these metals, those beautiful blue, red and green colors are obtained on the screen, and they are also used in the speakers and other circuits. And in case you didn't know, the phone is able to vibrate thanks to neodymium and dysprosium. These elements are not only important for the smartphone, but for our current technology, many of the modern devices such as televisions, cameras and laptops use components that contain this group of elements.
But let's talk specifically about some of the components that have made our phones smart.
The touch screen
Without a doubt, one of the components that stands out the most from smart phones is the screen, it basically occupies the entire front area of the phone and allows us to access all the functions, that's why we breathe deeply when we drop the phone! Luckily they are very resistant and survive most falls, this is because they are glass-ceramic materials, they are manufactured mainly with aluminosilicate glass, a mixture of aluminum oxide and silicon dioxide, which is then placed in a hot bath of potassium nitrate (KNO2). On the other side, we can find some of the 17 elements that make up the rare earths, these are used to generate the colors of the screen so that it lights up properly.
Some of the elements that we can find being part of the screen of the cellular phone. Author: @emiliomoron.
But as we all know, the screen is more than a piece of glass, it responds when touched, this is the exceptional thing. Smart phones use a category of display called capacitive touch screens, which are electrical in nature , although the glass of the phone contains ions, this material does not conduct electricity, so it is covered with a thin transparent and conductive layer of indium-tin oxide is deposited on the glass forming criss-crossed lines forming a grid, the screen works as a capacitor, storing a small electrical charge, when you touch the screen part of this charge is transferred to your finger, and the phone processor detects the voltage drop and the position of it, and a program is responsible for executing the action, allowing it to work as a touch screen.
Representation of the operation of a touch screen. Author: @emiliomoron.
Most phones today use lithium-ion batteries. Basically this technology uses lithium-cobalt oxide as the positive electrode of the battery, although there are also versions in which the cobalt has been replaced by another transition metal, and the negative electrode of the battery is made of carbon in the form of graphite. During charging, lithium is ionized and moved towards the graphite electrode, and during discharge it returns to the positive electrode. And all the elements of the battery are housed in an aluminum casing.
Some components of the battery. Author: @emiliomoron.
The electronic components used by a smartphone are not much different than those used by any other modern electronic item. Essentially, the phone's processor is made of silicon, but it does not conduct electricity by itself, so it is doped with a variety of different elements, which can include phosphorus, antimony, arsenic, boron, indium, or gallium. On the other hand, the microelectrical components and wiring of the telephone are composed mainly of copper, gold and silver. And we can also find tantalum, which is the main component of microcondensers.
Some of the elements found in the components of the electronics Source: image edited by @emiliomoron, original from pxhere.com.
Both the microphone and the speaker of the phone contain magnets, which are usually neodymium, gadolinium and praseodymium alloys. Other magnets are used in the phone's vibration unit, which are made of neodymium, terbium and dysprosium alloys.
And we can also find elements such as tin, copper and silver forming the solder joints that join the electrical components.
The composition of the housing will depend mainly on whether it is made of metal or plastic, although we can find a mixture of both. Metal housings are usually made of magnesium alloys, while plastic housings, therefore, are carbon polymers.
Some housings may contain brominated compounds, as they are the most effective flame retardants available to the plastics industry today, and are used as flame retardants in various electronic equipment, including cellular phones.
Some of the elements found in the housing. Author: @emiliomoron.
Conclusion and contribution
There are many chemical elements forming part of our smart phone, either in a pure state or forming compounds, and thanks to these, cellular technology has been able to advance to this point.
Although there are many details and additional information about the operation of smart phones, in this post I wanted to highlight how chemistry is present in these devices for everyday use, something that can help us as a teaching tool to educate our children and students about the chemical composition of the elements around us, since generally, when we address the issue of the periodic table of the elements in basic chemistry we do not associate the importance of the chemical elements for our daily lives.
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