Ok, it is time to speak up. I have read several sites now that list the greatest inventions ever, or of the 20th century, or the greatest engineering achievements ever. See the following links, for example.
In my humble opinion, something is conspicuously missing from the lists, or listed way too low. From the title of this page, you can probably guess what I think is missing. Let's just list the top 20 achievements from the first link.
One thing I have seen mentioned sometimes is hay. Not something that comes to mind immediately when you think of a great discovery or invention, but when you think about it, it's not as crazy as it seems. I guess the discovery of hay made agriculture possible. Being able to store feed for animals for the winter months turned man from a hunter-gatherer into a farmer. At least, that's what my guess is...
One thing that is quite obvious from the list, is that many things depend on others. No computers without electronics, for example. No spacecraft without computers. No household appliances without electrification. Note that most of the achievements depend directly or indirectly on electricity.
So, now ask yourself the question: how do we transport electricity?
Got the answer? Cables, wires, or cords, whatever you want to call them. They all boil down to an electrically conducting metal (usually copper) covered by some kind of insulating material. You need something to insulate electrical wires to avoid short circuits, electrocution and all sorts of other nasty things.
In the old days (long time ago), materials like paper and cotton were used as insulators. We have better stuff for that nowadays (drum roll): plastic(s)!
For the nitpickers. You could argue that the correct word would be polymers. I'll just keep on saying plastics.
So, although you could possibly replace plastic insulators for some applications with some other materials, it just doesn't work in most cases (ever seen the inside of a computer? think you could build it with paper-insulated wires?).
I could go on and on, but the bottom line is this. In the top 20 list above, the following would not be possible without electricity (which requires plastic): Electrification, Automobile, Airplane, Electronics, Radio and Television, Computers, Telephone, Air Conditioning and Refrigeration, Spacecraft, Internet, Household Appliances, Laser and Fiber Optics, and Nuclear Technologies. Some of the few remaining ones are probably also impossible without plastic, but I want to be conservative in my assessment.
Obviously there are more applications where plastic is essential other than the ones related to electricity. Take food packaging for example. Or clothing. There are many more examples. Just look around you at the stuff you are using and depending upon. Now imagine that you would have to replace all plastics with wood or metal or wool or cotton or something. Plastics are essential to modern society.
Some more advantages. Plastic is cheap, durable, light, usually non-toxic, it can be molded into almost any form, it resists corrosive chemicals, and can often be recycled.
So, does plastic have no disadvantages? Sure it does. Its durability is a double-edged sword. Plastics typically do not decompose by themselves, so if plastic waste is dumped in nature, it may take a very long time for it to disappear. Also, some plastics (like PVC -- polyvinylchloride) contain chlorine, which may cause some problems when they are burned.
An example. In the Netherlands (many years ago), it was established that public waste processing (burning) facilities had unacceptably high emissions of dioxins. Now, dioxins are a class of chemicals that are very bad for your health, even in very low concentrations. Very nasty stuff. One of the causes for the dioxin emissions was the PVC in household waste. The furnace temperatures of the waste processing facilties were too low to decompose the dioxins caused by the burning of PVC. As a result, PVC, and by association all plastics, got a reputation as being "very bad for the environment." You could also argue that the waste processing plants needed to burn household waste at a higher temperature.
Another thing. I have seen carbon dioxide described in the media as being "very harmful". I'll be the first to support lowering CO2 emissions, but I can't help wonder if someone confused "dioxide" with "dioxine". The latter being very harmful indeed, the former being somewhat of a problem...
Last remark about plastics and the environment. Again in the Netherlands, many people were convinced that you should buy milk in (reusable) glass bottles, rather than in (plastic coated) carton containers. Plastic is "bad", you see, and the fact that the glass bottles were reused meant that they were much "better" for the environment. Never mind the chemicals used to rinse and disinfect the glass bottles, or the fact that the bottles had to be transported back to the milk factory. Guess diesel trucks have no impact on the environment.
Another disadvantage. Most plastics burn quite easily, and emit rather toxic fumes when burning. Especially in clothing, chemical additives are needed to make it less combustible.
Plastic is an essential material in modern society, and should at least be in the top 5 of the all-time greatest discoveries and inventions. But that's just my opinion.
All this inspired by Gerrit A. Blaauw, Professor of Computer Science (at the time) at the University of Twente in the Netherlands. Quote: "The introduction of computers is important, but we should not overestimate its significance. The introduction of plastics had a far greater impact on society."
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