An exploding car with no one around to hear it does *not* make a sound.
A simple variant of the age old question of "If a tree falls in a forest and there is nobody around, does it make a sound?" A philosophical question, indeed. Before we can delve into the affirmation of what I am going to be arguing for, we must analyze connotations of the words and what the sentence entails. Now, what is the definition of sound? Now after googling the definition of sound, I've come upon 3 sources. According to dictionary.reference.com, meriam webster, and the free dictionary, two definitions of sound are prevalent; The stimulated sensation of vibration perceived by the sense of hearing, and the mechanical vibrations traveling through the air themselves.
So 'sound' is either the vibration become perceived, or the vibration themselves. However, is it wrong to say it can be both? All three websites accept both definitions and one definition does not hold more validity than the other. Both are authentic definitions of 'sound'. So, is it really incorrect to justify that there is an absence of sound if nobody is around to perceive that sound? Of course not. According to one definition of sound, it's entirely reasonable to argue that there is no sound when the car explodes, due to the circumstances. However, that's just a matter of semantics, which is simply a prelude to the main points of my argument.
Now, let's bring up an interesting theory. What if, reality isn't 'real'? What if, the exploding car did not make a sound, or even, did not exist? This brings forth the idea of solipsism, which is, to summarize, the idea that only a person's own mind is sure to exist, and that everything perceived by the external senses (i.e. taste, touch, hearing, smell, sight) is unsure to exist and might not exist outside of the mind. If there is a car that explodes and nobody is around, how are you sure it existed? Oh, you see the wreckage and perhaps the ground is littered with debris and marks from a seeming explosion; that is, if you assume that without observation, your reality followed the correct sequence of order to arrive at the outcome, being that 'A: The Car Exploded' automatically leads to -> 'B: The area around the car shows common signs of explosions' and more importantly, is implied to have made a sound because of it.
But how are you so sure these events happened in order? If you believe in the laws of physics and reality itself, having trust that everything outside of your mind is independent of it, including the laws of science and the people that have discovered the laws of science, are in fact, real, then sure. But solipsism challenges that. If you were not there to observe it, to perceive the sound, much less have another entity perceive the sound and give you some falsely credible assurance that the car indeed did make a sound, how do you KNOW it makes a sound? It's an assumption that the car made a sound, and an assumption that the car exploded. This falls under the biggest assumption of all; That everything you perceive of the external world is real, and not constructs of your mind. Jokingly, perhaps you are hooked up to a machine like the ones in the Matrix? Perhaps your reality is simply constructed to 'make sense', but outside of what you observe, it is pure chaos? You can't prove the car has made a sound if you do not believe that your perception of the world is false; It would be like trying to prove logic with logic, you just can't. Most people operate on the assumption that their logic and reason are trustworthy and infallible, and that it coincides with the assumption that what they perceive is real. But that's not the case if you throw solipsism in there.
Woah boy this is kind of long. I'll keep the last paragraphs short and concise. Well I've been arguing for my case using philosophical thoughts, ambiguity, and assumptions. Well I'm going to put a bit of science in there, I suppose. Now, according to quantum physics, in theory, matter that is not observed does not 'exist'. Yep, I said it. According to wave-particle duality, after some tests on photons, it was discovered that they could either be waves or particles according to what is used to observe them. However, it is never both. It is impossible to perceive something as both a particle and a wave, it is always one or the other. Furthermore, when not observed, matter does not exist at a single point of space and time. So that brings to question, what is sound when not observed? From this point on, it's all speculation, I admit, but it's credible speculation. We all know that vibrations are sort of like waves, and that is what sound is. Waves traveling through the air. Waves and vibrations are not exactly the same, but it's close enough for the point I'll be arguing from.
To reiterate, if sound is not observed, what happens? Can it even be perceived? Can it even be called sound? According to wave particle duality, it can't even exist as sound unless something perceives it. Perhaps it's a wave, perhaps it's a particle. But it is definitely not sound if it is obscure. The existence of sound is surely not like a coin, where it is 50/50 for the coin to land on heads or tails. However, the existence of sound is under question when there is nothing to observe it. Is it a wave or is it a particle? Furthermore, perhaps it doesn't exist when it's not observed, bringing a bit of pseudo-solipsism.
And besides, all things considered, you never said the location of the car in the parking lot. How do you know the parking lot is not in space, a vacuum, where sound can't travel at all? A bit of food for thought. ;-)