🧵 Materials and making

Glass starts out as ordinary sand, mostly a material called silica, which gets mixed with other ingredients and heated in a furnace until it becomes glowing, syrupy liquid hot enough to melt metal. While it is still soft and liquid, that molten glass can be poured, blown, or pressed into almost any shape, from a window pane to a drinking cup. As it cools back down, the glass hardens into the hard, clear material you know, but it never rearranges into a neat crystal pattern the way ice or salt does.

Paper usually starts as wood, which gets chopped into chips and mashed with water into a soupy mixture called pulp, breaking the wood down into countless tiny plant fibres. That watery pulp is spread out thin across a moving screen, where the water drains and drips away, leaving the fibres behind in a thin, damp sheet. Rollers then press and dry that sheet, squeezing the fibres tightly together until it becomes the smooth, sturdy paper you can write or draw on.

Metal and wood in the very same room are actually the same temperature, but metal pulls heat away from your skin much faster than wood does, which is why metal always feels colder to the touch. Materials that pull heat away quickly are called good heat conductors, and metal is packed with tightly connected particles that pass heat along rapidly, almost like a very efficient bucket chain. Wood, on the other hand, is a poor heat conductor, so it barely pulls any warmth from your fingers at all, which is why it feels closer to your own body temperature.

Cotton starts as a soft, fluffy fibre growing around the seeds inside a cotton plant's pod, which farmers pick once the pod has fully opened up. Machines then clean the cotton and twist those short, fluffy fibres together into long, strong threads, a process called spinning. Those threads are woven or knitted together into fabric, which is then cut and sewn into the actual shape of a shirt, a sock, or any other piece of clothing.