Like every Friday, the "Physics Tidbit" corner is back to make your weekend a little more interesting.
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Watch the video. What do you see?
That's right — it's a model of an external combustion engine called a Stirling engine. It bears the name of its inventor, who created it back in 1816.
But there's something else you're seeing without even realizing it, and it's just as fascinating.
The video shows a transition between 3 forms of energy: chemical potential, thermal, and kinetic.
The candle's fuel contains potential energy — it's there, but it performs no work and generates no heat as long as the candle is unlit. This energy stems from the candle's chemical structure.
When the candle is lit, the potential energy converts into thermal energy — the flame burns and produces heat.
The heat from the candle transfers a great deal of energy to the oxygen atoms inside the piston, causing them to expand and create mechanical motion — kinetic energy.
During the back-and-forth motion of the piston, some of that energy is lost and converted back into heat — only this time, the heat dissipates into the surrounding air and can no longer perform work.
And so the energy that was born somewhere in the core of the Sun reaches the end of its journey, because it cannot be used again without investing more energy than the process would yield.
video credit: @physicsfun
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