Microwave some corn kernels and a bit of magic makes popcorns. When I was a kid, I thought that popcorns can only be made in popcorn bags and that they must have butter for it to work.
I had no idea why microwaving the bag made popcorns but I knew that the sound associated with the bag was indicative of the progression of the popcorn making process.
Now, I realize at the heart of popcorn making is not magic, but science. Actually, all you need is sufficient heat and some popcorn kernels.
Although popcorn kernels seem dry, they are not devoid of moisture. When you heat up the popcorn, the water inside expands significantly. So when the pressure due to water expansion builds up significantly, the kernel breaks. The volume increases and the internal pressure drops to atmospheric. The fluffiness is due to the low density which arises due to this volume expansion.
I think the popping sound is due to the expansion rate being faster than the speed of sound. I'm not sure. It might just be the shell breaking. I guess a high speed camera may be able to provide some answers.
Saturday, 19 December 2015
Saturday, 5 December 2015
scientific terms
Recently, I've been thinking about definition of various things. In science, many things are defined operationally. I've come across some questions about whether glass is liquid or solid. There has been some misconception suggesting that glass is liquid and Derek addresses this (https://www.youtube.com/watch?v=c6wuh0NRG1s&feature=youtu.be&a).
But more importantly, it brings to light some interesting general problem. We have definitions and boundaries. Solids are things where atoms do not flow... but on what time scale? If you wait for a long time, solids can also "flow" (such as the earth's mantle). Are solids and liquids a continuum in actuality?
Like Derek suggests, these definitions and classifications create misconceptions. More troublesome is the fact that it creates a mental block. Is the world really made up of solids and liquids? I think no. These are models introduced by humans. I think by giving them names and using these term routinely, we forget that they are models describing the physical world around us. It is well known that there is a close tie between culture and language. But it seems language really shapes the way we think even in science. There is no perfect observer without bias.
But more importantly, it brings to light some interesting general problem. We have definitions and boundaries. Solids are things where atoms do not flow... but on what time scale? If you wait for a long time, solids can also "flow" (such as the earth's mantle). Are solids and liquids a continuum in actuality?
Like Derek suggests, these definitions and classifications create misconceptions. More troublesome is the fact that it creates a mental block. Is the world really made up of solids and liquids? I think no. These are models introduced by humans. I think by giving them names and using these term routinely, we forget that they are models describing the physical world around us. It is well known that there is a close tie between culture and language. But it seems language really shapes the way we think even in science. There is no perfect observer without bias.
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