system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: what determines whether a substance is solid liquid or gas at room temperature?
gpt
Intermolecular forces. Some molecules like to stick together, others don't. If they really like each other, they form a solid. If it's more like a friendship they form liquids. If they rather stay away from each other they form a gas. You can force molecules together by cooling them down, which decreases their ability to move around. Or you can increase the pressure. What determines wether molecules like each other or not? It depends on their chemical structure. Some molecules, like water, are polar. They are like tiny magnets that attract each other. Water molecules bond together at room temperature, but they still have enough energy to move around a bit, so that's why water is a liquid and not a solid.