When the Wells Run Dry: Energy and  Motion Are Crippled, the Humble Bicycle Takes Over.

I have written several articles concerning about how the closure of the Straits of Hormuz affects the global flow and prices of oil. I have written about the rise and fall of mankind. I have also written the bicycle as mankind greatest invention. The last article I wrote was what will happen when the last drop of oil runs dry. Here are the links:

https://scientificlogic.blogspot.com/2026/03/geography-controls-flow-of-oil-when.html

https://scientificlogic.blogspot.com/2026/04/from-fire-to-fallout-ascent-burden-and.html

https://scientificlogic.blogspot.com/2026/04/the-bicycle-is-greatest-invention-ever.html

 

https://scientificlogic.blogspot.com/2026/04/when-last-drop-runs-dry-quiet.html

 

Let me go back to the bicycle  as our greatest of inventions when we face a crisis. 

There are moments in history when humanity is quietly advised to reconsider its path, and others when circumstances compel it to do so. The rising cost of petrol in recent times, exacerbated by tensions in the Middle East and the vulnerability of the Strait of Hormuz belongs to the latter. It is not merely a fluctuation in price; it is a reminder of how deeply our civilization depends on a resource that is finite, fragile, and unevenly distributed.

For more than a century, oil has been the unseen force behind modern life. It moves our vehicles, sustains global trade, and forms the basis of countless materials that surround us. Yet oil is not a gift that renews itself within human timescales. It is the compressed residue of ancient life, accumulated over millions of years and consumed within a few generations. When supply is threatened, as it is now, the illusion of permanence dissolves quickly.

Nowhere is this dependence more evident than in transportation. Our cities are designed for cars, our distances defined by speed, and our habits shaped by the assumption that fuel will always be available. But what happens when that assumption begins to fail?

To answer this, it is helpful to step back and examine a simple yet profound comparison between the motorcar and the bicycle.

A litre of petrol contains an astonishing amount of energy, approximately 34 million joules. In a typical car, this single litre can carry a person about 12 to 15 kilometres, depending on efficiency and driving conditions. At first glance, this seems impressive. Yet the internal combustion engine is inherently inefficient; much of that energy is lost as heat, noise, and friction. Only a fraction is converted into useful motion.

In contrast, the human body, though far less powerful, is remarkably efficient when paired with a bicycle. A person cycling at a moderate pace expends roughly 100 to 150 watts of power. Over the course of an hour, this translates to about 400,000 to 500,000 joules of energy. With this modest expenditure, a cyclist can travel 15 to 20 kilometres.

If we compare these figures carefully, a striking truth emerges. The energy contained in a single litre of petrol is enough, in principle, to propel a bicycle hundreds of kilometres if it could be converted with similar efficiency. Instead, when used in a car, it moves a much heavier machine only a fraction of that distance.

The bicycle, therefore, is not merely a simple device; it is one of the most efficient energy converters ever devised. It transforms human metabolic energy into motion with minimal loss, extending our natural capacity many times over. In terms of energy per kilometre per person, it far surpasses the automobile.

This comparison is not intended to diminish the usefulness of cars, which have undoubtedly transformed society. Rather, it highlights the imbalance that has developed. We have come to rely on a system that consumes immense energy for relatively modest gains in mobility, while overlooking alternatives that are elegant, efficient, and sustainable.

Before the age of oil, movement was slower, but it was also more balanced. People walked, cycled, or relied on simple mechanical and animal-powered systems. Distances were meaningful, and communities were often more localized. Today, while we cannot and should not abandon the advantages of modernity, we may need to recover some of that balance.

The bicycle offers a compelling path forward. It is accessible, affordable, and independent of fossil fuels. In urban environments, it can often rival or even surpass cars in efficiency and speed, especially when congestion is considered. For longer distances, it can be integrated with public transport systems, forming a hybrid model of mobility that is both practical and sustainable.

Beyond human-powered transport, we must also look to the natural forces that surround us. The wind that turns turbines, the sunlight that falls freely upon the Earth, and the flowing water that descends from higher ground, all represent sources of energy that do not diminish with use.

These renewable energies may not yet fully replace fossil fuels, but they offer a direction, one that is not constrained by depletion or geopolitics. Unlike oil, they are not concentrated in a few regions of the world; they are distributed, abundant, and continuously replenished.

The present crisis, therefore, is more than an economic challenge. It is an invitation to rethink our assumptions about energy, mobility, and progress itself. Must we always move faster, farther, and with greater consumption? Or can we learn to move wisely, efficiently, and within the limits of what the Earth can sustain?

In the quiet turning of a bicycle wheel, there is a lesson. It reminds us that progress need not always be complex, that power need not always be vast, and that sometimes the most enduring solutions are those that is in line closely with the natural capacities of the human body and the rhythms of the world around us.

When the wells of oil one day run dry, and that day will surely come—it may not be the most advanced machines that carry us forward, but the simplest ones, guided by deeper understanding.

And perhaps, to my gentle readers, that is not a step backward, but a step toward wisdom.

 

My Boyhood Catapult to the Forensic Language of Impact:

 

From a Boyhood Catapult to the Forensic Language of Impact: A Reflection on Energy, Pressure, and the Memory of Matter

There is something profoundly poetic in the way my early fascination with a simple catapult has led me into the deeper truths of physics and forensic science. What seemed like a child’s play launching stones against tin cans and observing the dents—was in reality an intuitive exploration of nature’s laws. Those small indentations were not merely marks on metal; they were physical records of energy transfer, force concentration, and material response.

At the heart of all motion and impact lies a simple yet powerful relationship:

This equation tells us that kinetic energy depends not only on mass, but more significantly on velocity. The squaring of velocity means that even modest increases in speed result in dramatic increases in energy. This is why a small, fast-moving bullet can rival or exceed the effects of much heavier but slower-moving objects when it comes to penetration and localized damage.

Let us return, for a moment, to that mischievous  boy (me) playing with the catapult in school 

A small stone of mass , travelling at about , carries an energy of:

This is a modest amount of energy, yet when the stone strikes a tin surface, it stops over a very short distance. Using the relationship:

and assuming a stopping distance of , the force becomes:

When this force is applied over a small contact area, say , the resulting pressure is:

It is this concentration of force into a small area that produces the visible dent. Even with relatively low energy, the pressure is sufficient to exceed the yield strength of softer metals. What I  observed was, in essence, the threshold at which matter begins to permanently deform.

Now, as we move into the realm of firearms, the same principles apply but on a vastly different scale.

A typical 9mm bullet, carrying about of energy, comes to rest over a much shorter stopping distance, approximately . Applying the same reasoning:

If this force is distributed over a contact area of roughly , the pressure becomes:

Here, we enter a regime where the pressure exceeds the strength of most structural metals. The bullet deforms, flattens, and transfers its energy efficiently into the target. The deformation itself is part of the energy dissipation process, and the resulting marks,  flattening, radial cracks, and indentation patterns—become valuable forensic clues.

When we consider a high-velocity rifle bullet, the situation becomes even more dramatic. With an energy of approximately , and an even shorter stopping distance of , we find:

With a smaller contact area of about , the pressure rises to:

At such extreme pressures, materials behave in ways that defy everyday intuition. Steel may momentarily flow, microscopic cracks propagate violently, and shock waves travel through the material. The impact resembles, in some respects, a miniature meteorite collision. The resulting damage, penetration, fragmentation, and spalling, leaves behind a complex signature that can be studied and interpreted.

And yet, when we shift our attention to something as massive as a car, the story changes.

A car of mass , travelling at , possesses:

This is hundreds of times greater than the energy of a bullet. However, because this energy is distributed over a large area and dissipated over a longer stopping distance, the resulting pressure is far lower. Instead of piercing, the car deforms and crushes. This illustrates a central truth: it is not energy alone, but the concentration of energy in space and time that determines the outcome of an impact.

To understand how materials ultimately fail, we turn to fracture mechanics. The critical relationship is expressed as:

This equation describes how stress () interacts with microscopic cracks of length within a material. When the stress intensity factor exceeds the material’s fracture toughness, cracks propagate rapidly, leading to failure. High-velocity impacts dramatically increase , activating even the smallest imperfections within the material.

 

High-velocity impacts dramatically increase σ, activating even the smallest imperfections within the material. What appears to be a solid, uniform surface is, at the microscopic level, a landscape of potential fracture points waiting to be triggered.

It is here that physics meets forensic science - an area I am familiar at Cambridge 

Every impact leaves behind a record—a silent testimony encoded in deformation, cracks, and residue. By examining penetration depth, investigators may estimate energy using:

By analysing momentum:

and changes in momentum:

they can infer whether a bullet ricocheted, penetrated, or fragmented. The angle of impact, the type of weapon, and even the distance from which the shot was fired can often be reconstructed from these physical clues.

Surface features tell their own story:

• Smooth dents suggest lower pressures and ductile deformation
• Sharp fractures indicate high strain rates and brittle failure
• Spalling reveals intense internal stress waves

Thus, the material itself becomes a witness.

And so, dear readers we come full circle.

The young boy- that’s  me  observing dents in a tin with a catapult was already engaging with the same principles that modern forensic scientists use to reconstruct events from the smallest traces. What began as curiosity has matured into understanding, and what seemed like simple play has revealed itself as an encounter with the fundamental laws governing matter and motion.

There is a quiet elegance in this continuity that the same physics governs a stone from a catapult, a bullet from a rifle, and the conclusions drawn in a forensic laboratory. The language is consistent; only the scale changes.

And perhaps the most beautiful insight of all is this:

Matter remembers.
Every impact, no matter how brief, leaves behind a story waiting for a mind as curious as anyone who  read it - just to share my memories of yesteryears