Another delay in posting, so apologies again, but at least I’m only a day late this time. Anyway, here it is, and this week I’m going to delve into the Laws of Sir Isaac Newton.

Whether you’re kicking a football, driving a car, or watching a rocket launch into space, you’re seeing Isaac Newton’s laws of motion in action. Just take a moment, and imagine you’re sitting on a bus, and the driver, without warning, suddenly slams on the brakes, and your body lurches forward. Why does that happen?

Or imagine a football soaring across the pitch after a powerful kick from Harry Kane has sent the ball screaming into the back of the net from 30 yards out. What is it that makes it speed up, slow down, and eventually stop?

And how does a rocket, weighing hundreds of tonnes, actually manage to leave Earth and get into space?

The answer to all of these questions, and many more, can be traced all the way back to three ideas developed by Sir Isaac Newton more than 300 years ago. Published in 1687, Newton’s laws of motion became the de-facto foundation of classical physics and at the same time transformed our understanding of how the universe actually works.

It is remarkable that these laws are simple enough to explain everyday events while being so powerful they can help send spacecraft into orbit.

Now my faithful few, it’s time to dive in and take a closer look.

Let’s start with the First Law and look at why things don’t like to change.

Newton’s First Law is often called the Law of Inertia, which in simple terms, says that things tend to keep doing whatever they’re already doing. An object sitting still wants to stay sitting still, and an object moving along, minding its own business as it travels in a straight line wants to keep moving along, minding its own business, travelling in that same direction at the same speed. It will only change speed or direction if some force acts upon it causing it to do so.

As obvious as this may sound now, at the time it was a revolutionary idea.

Before Newton came along, most folk believed that motion required a constant force, which, if you think about it, in everyday life seems true. Roll a ball across the floor and it eventually stops. Newton, however, realised the ball doesn’t stop because moving objects naturally come to rest. It stops because forces such as friction and air resistance are working against it and if you were to remove those forces the ball would keep rolling indefinitely, and that tendency to resist changes in motion is called inertia.

You experience inertia every day. It’s why passengers lean forward when they are traveling in a bus and the driver brakes suddenly. All their bodies are simply trying to do is continue moving at the speed they were already travelling.

Newton’s Second Law applies to what happens when you push things. We all know that objects don’t always trundle along, moving in the same way. They can speed up, they can slow down, and they tend to change direction all the time. This is where Newton’s Second Law comes in.

It explains the relationship between force, mass, and acceleration, and in its formulaic state it is usually written as F = ma. In other words, force equals mass multiplied by acceleration. The idea is straight forward enough, the harder you push something, the greater its acceleration is. But the heavier the object, the more force you’ll need to produce the same effect.

Imagine you are pushing an empty shopping trolley along the isles of your favourite supermarket. It moves easily (unless you’ve got the one with the dodgy wheel). Now fill it with your weekly shop and suddenly it takes much more effort to get it moving. The force you’re applying might be the same, but the mass has increased.

This beautiful law is one of the most useful tools in science and engineering as it helps designers calculate everything from the power of a car engine to the thrust needed for a rocket launch.

That takes us nicely onto Newton’s Third Law. And that is, every force has a partner in crime.

By now, you might be wondering how movement starts in the first place, and the third law explains this. And this is the famous saying you have heard many, many times before, as Newton said, “For every action, there is an equal and opposite reaction.” Put simply, this means that whenever one object pushes on another, the second object pushes back with exactly the same force in the opposite direction.

Let’s take something as simple as walking down the street as an example. Most of us simply assume that, when walking, they move forward because their legs push them ahead. But, this isn’t the case as what actually happens is way more interesting. As your foot pushes backward against the ground, the ground pushes forward against your foot, and that reaction force propels you forward. Exactly the same principle explains swimming. As you push water backward, the water pushes you forward. It also explains rocket launches. As engines expel hot gases downward, those gases push back on the rocket, which sends it upward, soaring into the sky and beyond.

Without Newton’s Third Law, space travel wouldn’t be possible.

If you’re looking for proof that Newton’s laws aren’t just dusty ideas from a physics textbook, look no further than Apollo 13.

In the 1995 film, Tom Hanks portrays astronaut Jim Lovell, commander of the ill-fated lunar mission that suffered a catastrophic explosion on its way to the Moon. At one point, with the spacecraft’s systems being shut down to conserve precious power, Lovell turns to his crew and says:

“We just put Sir Isaac Newton in the driver’s seat.”

It’s a great Hollywood line, but it’s memorable because of its roots in reality.

The real Apollo 13 mission faced a daunting physics problem. After the explosion, the crew had to nurse a crippled spacecraft home from hundreds of thousands of miles away, with power limited and most of the systems switched off, so they could no longer rely on their computers in the normal way. Instead, they had to trust in the laws of motion and gravity, Newton’s laws, to carry them around the Moon and safely back to Earth. Even seemingly harmless actions could become a problem. The crew were warned by Mission Control not to vent any waste from the spacecraft  into space as this might create a small thrust, tiny enough that it could nudge them off course. In the vacuum of space, where there is no air resistance to slow things down, even tiny forces matter, and that is what Jim Lovell meant by “putting Newton in the driver’s seat.” The astronauts were placing their faith in the very laws Newton had described nearly three hundred years earlier.

The First Law kept the spacecraft moving along its path once it was set in motion, and the Second Law explained how small, carefully planned engine burns would alter their path when course corrections were needed. The Third Law explained why those engine burns worked at all, as gases expelled in one direction pushed the spacecraft in the opposite direction.

It’s one of those rare moments where science, history and popular culture intersect perfectly. At the height of the Space Age, surrounded by cutting-edge technology, three astronauts ultimately trusted one of the oldest and most fundamental ideas in physics. When everything else seemed uncertain, Sir Isaac Newton was still safely at the wheel.

As individually simple as Newton’s laws are, they produce a powerful picture.

The first tells us that motion doesn’t change without a force. The second tells us how much motion changes when a force is applied. The third explains where many of those forces come from in the first place.

Together, the three laws create a complete picture of how objects move, interact, and respond to the world around them. From bicycles and footballs to aircraft and planets, these three principles describe an astonishing range of motion.

More than three centuries after Newton wrote them down, they remain among the most important ideas in all of science.

So, the next time you’re on a bus and the driver brakes suddenly, or you’re at the footy and a screamer hits the back of the net, or you‘re watching Apollo 13 and Tom Hanks utters that famous line, you’ll be witnessing those three elegant laws at work.

Although the technology may change, the universe is still playing by Newton’s rules.