The history of neutrons is highly complicated and extremely fascinating at the same time! A cousin of the proton, the neutron lies at the centre of the atom too. It is a major part of the nucleus. But here is the real surprise – it has no charge! Unlike protons, which actually carry a positive charge.
Interested already? This is just the beginning of neutron’s very interesting story! After this brief introduction to one of the tiniest subatomic particles on this planet (perhaps even the universe), it is time to move onto some very important and very exciting questions such as –
- Who discovered the neutron?
- How was the neutron discovered?
If you want the answer to these thrilling questions, there is only one left to do – keep reading!
What is a neutron?
Before we begin, let us decode what a neutron is. As we mentioned before, it is a very small, extremely tiny particle, found at the very centre of an atom – more specifically within its nucleus. It does not contain any electric charge, which is why the word “neutral” is kind of in its name. When it comes to the mass of a neutron, there is hardly any difference between its mass and a proton’s.
Curious about its purpose now? That is simple. Neutrons create balance. Think of them as particles that keep the entire nucleus stable by balancing all the repulsive forces that exist between protons due to their positively charged nature.
How was the neutron discovered?
Let us begin with the topmost question on your mind, although we are afraid, we will have to dig a little deeper into history to answer accurately “how was the neutron discovered?” But we promise, you will quite enjoy this very scientific and “electrifying” sneak-peek into the past! Let us begin.
You see back in the year 1930, two German physicists – Herbert Becker and Walther Bothe made a startling discovery one fine day. They found that when polonium’s alpha particles hit light elements such as boron, beryllium, or lithium, they ended up releasing a very strong type of radiation.
What was more interesting is that this radiation did not respond to electric fields – it remained entirely unaffected, which led these German physicists to believe it was gamma rays. Little did they know that they were laying the groundwork for one of the most important scientific breakthroughs this world has ever seen!
Fast-forward to the year 1932 in France, the scientific husband-wife pair of Frederic and Irene Joliot-Curie discovered that this same radiation was capable of knocking out high-energy protons from hydrogen-rich materials such as paraffin wax.
What did this prove? That what Becker and Bothe found was not gamma rays. It was something else entirely. Something new. Something that was unknown to the world up until that point. What happened next was that the Italian physicist, Ettore Majorana, proposed that the reason why the ejection of protons was possible was because of the presence of a neutral particle within the atom.
This is both interesting and significant because in the year 1920, nearly a decade ago, English scientist, Ernest Rutherford, had suggested that a neutral particle most likely existed in the nucleus of an atom. He theorized it was made up of a proton and an electron, so he christened it “neutron”.
That, in a nutshell, entails the discovery of neutrons experiment.
But it does not spell out the exact experiment, right? Neither does it say who discovered the neutron. So far, it is more about laying the groundwork for its discovery rather than detailing its actual discovery.
Well, you are in luck as we have saved the actual discovery of neutrons experiment for you below! Condensed into easy-to-digest bullet points, this will help you comprehend and retain the complex process of neutron’s discovery so you can easily ace your school tests and quizzes like a science-wiz!
- Sir James Chadwick, the very famous British physicist who gets credit for laying the groundwork for the discovery of the modern-day atomic bomb, is the answer to your question of “which scientist discovered the neutron”. He conducted an experiment which revealed that alpha particles from polonium when aimed at beryllium sheets led to the production of a very strong yet uncharged radiation.
- Intrigued by his discovery, Chadwick then directed this radiation at paraffin wax. Paraffin wax is rich in hydrogen so when the radiation came in contact with it, it ended up expelling protons. This validated the existence of a neutral particle within the atom, but it was not enough to prove it.
- Next, Chadwick did something no one else had thought of before. He used an ionization chamber to detect the expelled protons as well as to measure their range. He also used the chamber to study the interaction of this radiation with different types of gases.
- The results were not just eye-opening – they changed the world. Specifically, the scientific world. His experiments led him to conclude with conviction that this radiation was indeed made up of neutral particles. In fact, these neutral particles were actually identical in mass to who they shared space with inside the atom – namely the protons. These neutral particles were later called neutrons.
Who discovered neutrons?
As we told you before, neutrons were discovered by Sir James Chadwick. So, if anyone ever asks you, “which scientist discovered the neutron?”, give them this answer with confidence. Be cautious though, and do not confuse his fellow British physicist, Ernest Rutherford, with him. The primary contribution of Ernest Rutherford was in theorising the existence of the neutron as well as christening it.
That is not to say his role should be underestimated. Without his theory, scientists that came after him would have probably never tried to look for the neutron. However, he was not the physicist who discovered it. Neither were Becker and Bothe the ones who did. In fact, the pair of Frederic and Irene Joliot-Curie was unsuccessful too. They all got close, but ultimately it was Chadwick who made this ground-breaking discovery.
Conclusion
Knowing the story behind neutron’s discovery can help you ace school tests and inter-school quizzes and competitions. It can also feed your curiosity about science and perhaps inspire you enough to make your own breakthrough discovery one day! Read our blog to fuel your passion for all-thing-science further!
