Water is a remarkable substance, present on Earth for billions of years. Every water molecule has traveled through various forms and living beings, including dinosaurs and bacteria. Earth's water, arriving from space via asteroids and comets, defies conventional chemistry. It should be a gas at Earth's temperatures and pressures, but it's a liquid. Uniquely, ice floats on water due to its expansion when freezing, which has helped life survive ice ages. Hot water freezes faster than cold, a phenomenon not fully understood.
Water molecules also exhibit capillary action, enabling plants to nourish themselves and blood to reach the brain. Water is abundant in our solar system, found on the Moon, Mars, and Pluto. Its presence suggests the possibility of life elsewhere.
This strange and essential liquid challenges scientific understanding, yet without its unique properties, life on Earth wouldn't exist.
Vocabulary:
• Molecule (noun): The smallest unit of a chemical substance that can exist independently.
• Cycle (noun): A series of events that are regularly repeated in the same order.
• Asteroids (noun): Small rocky bodies orbiting the sun.
• Comets (noun): Icy bodies in space that release gas and dust.
• Chemistry (noun): The branch of science concerned with the substances of which matter is composed.
• Capillary action (noun): The ability of liquid to flow in narrow spaces without the assistance of external forces.
Source: BBC Ideas