Why don't perpetual motion machines ever work? - Netta Schramm

Summary

The quest for a perpetual motion machine dates back to 1159 A.D., with Bhaskara the Learned's design for a mercury-filled wheel. Despite centuries of attempts, including self-sustaining systems like windmills and lightbulbs, perpetual motion machines remain impossible due to the first and second laws of thermodynamics. These laws state that energy cannot be created or destroyed, and energy inevitably dissipates through friction and heat. While inventors' dreams of perfectly efficient energy continue, the search for such a machine persists, with the hope that future discoveries might challenge the established scientific principles.

Takeaways

• 😀 Bhaskara the Learned first sketched the concept of a perpetual motion machine around 1159 A.D., which proposed a wheel with mercury reservoirs that could keep turning forever.
• 😀 Perpetual motion machines aim to create devices that do work indefinitely without requiring external energy sources, like a self-sustaining windmill or lightbulb.
• 😀 These machines have captured the imaginations of inventors due to their potential to revolutionize energy use, but they all ultimately fail due to fundamental laws of thermodynamics.
• 😀 The first law of thermodynamics states that energy cannot be created or destroyed, meaning any perpetual motion machine would only ever produce as much energy as it consumes.
• 😀 There is no energy left over from a perpetual motion machine to power other devices, which makes such machines unfeasible for practical use.
• 😀 Ideas based on Bhaskara's over-balanced wheel, using rolling balls or weights on swinging arms, still fail because the system's center of mass shifts, and the wheel eventually stops.
• 😀 Robert Boyle proposed a self-watering pot using capillary action, but this idea failed as the action would either prevent the water from falling or would be overcome by gravity.
• 😀 Other ideas, like magnet-powered devices, fail because magnets lose their strength over time or cannot keep the system moving indefinitely.
• 😀 Even if engineers could design a machine that didn’t violate the first law of thermodynamics, the second law of thermodynamics still poses an issue, as friction and heat loss drain energy.
• 😀 The second law of thermodynamics states that energy spreads out over time through friction and heat, meaning perpetual motion is impossible in the real world.
• 😀 Despite the challenges, there is still hope that new discoveries, such as exotic forms of matter or quantum phenomena, might eventually challenge the laws of thermodynamics, but for now, humanity’s search for perpetual motion continues.

Q & A

Who was Bhaskara the Learned and what was his contribution to the idea of perpetual motion?

Bhaskara the Learned was a mathematician from around 1159 A.D. who sketched a design for a wheel that contained curved reservoirs of mercury. His idea was one of the earliest concepts for a perpetual motion machine, where the mercury's movement would imbalance the wheel and keep it turning indefinitely.

What is a perpetual motion machine?

A perpetual motion machine is a device that can perform work indefinitely without any external energy source, theoretically creating a self-sustaining system. It aims to continuously operate without losing energy or requiring any input.

Why are perpetual motion machines appealing to inventors?

Perpetual motion machines are appealing because they could transform our relationship with energy. They could potentially provide an endless source of power, eliminating the need for external energy sources, such as fuel or electricity.

What does the first law of thermodynamics state?

The first law of thermodynamics states that energy cannot be created or destroyed. This means that a machine cannot produce more energy than it consumes, ruling out the possibility of a perpetual motion machine that generates excess energy.

Why do perpetual motion machines violate the first law of thermodynamics?

Perpetual motion machines violate the first law of thermodynamics because they would need to produce more energy than they consume, which is impossible. All machines can only convert energy from one form to another, never create extra energy.

What does the second law of thermodynamics explain?

The second law of thermodynamics explains that energy tends to spread out through processes like friction. In real-world systems, energy is always lost to heat, making it impossible for machines to keep running indefinitely.

How do friction and heat affect perpetual motion machines?

Friction and heat cause energy to dissipate in real machines, making it impossible for them to operate forever. These losses, no matter how small, ensure that the machine eventually stops working.

What was Robert Boyle's idea for a perpetual motion machine, and why did it fail?

Robert Boyle proposed a self-watering pot that relied on capillary action to cycle water around a bowl. However, the capillary action strong enough to lift water would also prevent it from falling back into the bowl, preventing the system from working continuously.

What is the role of magnets in some perpetual motion machine designs?

Some perpetual motion machines use magnets, with the idea that magnets would pull a ball upwards, making it cycle continuously. However, this design fails because the magnet's strength degrades over time, and without extra energy input, the machine would stop.

Why can't perpetual motion machines work even if they don't violate the first law of thermodynamics?

Even if a perpetual motion machine doesn't violate the first law, it would still be unable to work because of the second law of thermodynamics. Heat loss and friction would gradually reduce the machine's available energy, leading to its eventual failure.