SM: Leptons


Leptons in the standard model are defined as those fundamental particles which do not interact via the strong force. The strong force is one of the three fundamental forces in the standard model – the other two being electromagnetism and the weak force.

Leptons come in three different generations…


the electron, the muon and the tau and their associated neutrinos.

You may not have heard of neutrinos before but they are in fact all around is. They are created in the sun by a decay involving the weak force.


If you were to hold your thumb out then about 100 billion of neutrinos pass through it every second. You don’t feel it because neutrinos are very weakly interacting meaning they have to travel through a lot of stuff before having a sizeable probability of interacting. There is even an experiment in using part of the ice sheet of Antarctica to try and detect them – this experiment is affectionately called ICE CUBE.

Electrons are also worth a mention, since they pretty much determine the whole of chemistry. Most of the matter around us is made up of atoms…


… at the centre of which is a nucleus.  This nucleus is surrounded by electrons, held there by the electromagnetic force, and which in part determine the chemical properties of that atom.

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SM: Fundamental Forces

The standard model of particle physics contains 3 of the 4 fundamental forces in the universe: Electromagnetism, the weak force and the strong force.

The 4th fundamental force is called gravity (which I am guessing you are all familiar with). Gravity is the weakest of these forces, and its effect only comes into play at very large energies – much larger than the ‘standard model of particle physics’ is there to predict.

The other forces in the standard model are mediated by a types of particles called ‘Gauge bosons’…


The electromagnetic force is mediated by a gauge boson called the photon. Photons are all around, forming what is commonly termed as light. Although it is photons that we use to see they also allow electrically charged objects to attract or repel. For example when you touch a table a stream of photons moves from your hand to the table (or vice versa) causing a repulsive force.

The weak force is mediated by, not one, but three different types of Gauge boson. The weak force is responsible for certain types of decays. In particular without the weak force we would not have stars, since the mechanics they undergo to produce light and energy requires decays mediated by the weak force.

The strong force is mediated by a gauge boson called a gluon. As the name suggests this glues together matter. As you sit there reading this blog post, (nearly) everything around you is made up of atoms. At the centre of these atoms is a nucleus which is held (or should I say ‘glued’) together by the strong force.

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Discussions in Science

Each YouTube video will explore a different scientific topic. These will be informal, unscripted and unedited in an effort to show that science communication can be natural and to encourage you to talk more about science.

We might sometimes get things wrong but it’s the process of developing interest and raising questions which is important.

To us success isn’t driven by the number of views or likes (and that’s really hard for a marketer like Bradley to say) but the number of conversations we start . We do hope you enjoy watching our videos and start conversations about science @SiblingsinSci.

Science in the Social Network

Given that Facebook was founded in 2004 and Twitter two years later in 2006 you may think the impact of social networking on science was limited before the 2000s. But you would be wrong. Dead wrong. Take the example of the ‘Philosophiæ Naturalis Principia Mathematica’ otherwise known as Newton’s Principia which forms the foundation of classical (Newtonian) mechanics and Newton’s law of universal gravitation. As Tom Standage [1] explains, the Principia has its very origin in the social network sites of 1600s England – the Coffeehouses.

From discussions, to collaborations, from stories to experiments, the pre-2000 social networking sites had them all. And how we use social media today reflects how we used it then. A survey conducted in 2014 by Richard Van Noorden [2] into the social media use of over 3,500 researchers showed that many were using social media to discover peers, or find collaborators.

But ‘science in the social network’ is not just about scientist-to-scientist communication. It is also about how scientists share their information to the layperson. This is important to improve both the general literacy of the human population about the World around us and to inspire the next generation of scientists to go further and farther into the depths of understanding.


[1] Standage, T., 2013. Writing on the wall: Social media-The first 2,000 years. Bloomsbury Publishing USA.



We don’t like to admit it, but you’ve guessed it, we’re brothers! Bradley (above left) is a science communicator and Joseph (above right) studies physics. Together we are Siblings in Science.

This website will showcase our scientific achievements and blogs about science. Please feel free to drop us an email or you can follow us on twitter @SiblingsinSci.

We think the best way to learn science is to talk about it. And that’s exactly what we’ll be doing in our new YouTube videos. Here’s our latest video: