Molecules Reorganize To Make Up Everything In The Universe

by Virginia Quach, age 12

Just about every known substance in the universe is either a solid, liquid or gas. These are known as the states of matter.

You must have noticed how the ice in your lemonade melts when you’re lounging in the sun. The flavor is weaker when you take a sip, because the water diluted the refreshing drink. Substances change back and forth between states of matter when their temperatures and pressures hit certain thresholds. After sitting in the hot sun, the ice goes from solid to liquid. The melting point of a substance is the temperature at which a solid becomes a liquid. The highest temperature a liquid can reach before it becomes a gas is called the boiling point. This is why your popsicle melts when you take it out of the freezer. The freezer is at the popsicle’s freezing point or lower, but the room is much warmer, causing it to melt.

Have you noticed that sugar dissolves more easily in hot coffee than in cold coffee? The movement of molecules in a substance depends on temperature. Heat energy creates more vibration in molecules causing them to break apart from the bonds that hold them together. The water in the heated coffee adds energy tot he sugar molecules, which causes them to move around in the liquid instead of sinking to the bottom.

Solids have strength and shape because their molecules are tightly packed together and vibrate in place. Liquids have bonds that are loose, which allows them to take the shape of any container they are poured into. Gases don’t have shape or strength. Gases have fast-moving molecules that move all over the place, constantly breaking and reforming bonds that hold them together.

When a liquid is heated up, its molecules vibrate so much that they eventually break apart, spread out, and form a gas. This is called evaporation. For example, whenever you bring water to a boil to make pasta, the molecules vibrate more rapidly and evaporate, creating steam. When a gas cools down, its molecules slow down and bound together. The process by which a gas forms into a liquid is called condensation.

Solids, liquids, and gases make up the universe. They are a daily reminder that the universe is made up of billions of tiny molecules in different, beautiful arrangements.

[Source: The Big Book of Knowledge ]