system
Given the following post, respond as if you're commenting on Reddit:
human
How does concrete work?(powder + water = solid concrete????
gpt
Pretty much! Basically, concrete is cement mixed with rocks. Cement is basically crushed rock (limestone or something similar) that has been "cooked" at over 1500 degrees (F) for awhile. The cooking releases the oxygen in the rock (essentially burning it and releasing C*O*2), and then when you add the water, the oxygen in the water (H2*O*) recombines to reform the rock. Sometimes people add ash or sand as well. There are a ton of variations on the process that can produce stronger or more resilient types of concrete, but this is the basic idea behind it. Check out the wikipedia page for a little history (ancient Roman concrete is quite famously tough stuff) and some of the chemistry behind the other processes.