2. Seawater - 2.1. The water cycle Flashcards
What are atoms?
The tiny particles that make up all material
What are molecules?
Particles formed from atoms
What is particle theory?
The idea that we can describe all materials as a collection of very many tiny particles that are constantly moving
What happens when a material is heated?
The particles gain more kinetic energy and move faster and the temperature of the material increases
What unit measures the kinetic energy of the particles in a material?
Degrees Celsius
What are the 3 different physical states?
Solid, liquid and gas
Describe the arrangement of particles in a solid
Particles closely packed together; not enough space to move past each other
Describe the arrangement of particles in a liquid
Particles closely packed together; just enough space to move past each other
Describe the arrangement of particles in a gas
Particles far apart from each other; lots of space for particles to move past each other
Describe the motions of particles in a solid
Particles vibrating against each other in fixed positions
Describe the motions of particles in a liquid
Particles vibrating against each other and flowing past each other
Describe the motions of particles in a gas
Particles moving fast, colliding with each other
In which 2 physical shapes does a material take the shape of its container?
Liquid and gas
In which 2 physical shapes does a material have a fixed volume?
Solid and liquid
What happens when a solid is heated?
The vibrations increase and the solid expands slightly. With enough energy, the vibrations create enough space between the particles so they can move past each other - it’s now a liquid.
What is the melting point?
The temperature at which a solid becomes a liquid
What is latent heat energy?
The energy transferred to separate particles enough to move past each other
What happens to the temperature of a material as it is melting and at its boiling point?
It stops increasing (until the material has melted/evaporated)
What is evaporation?
When some liquid particles at the surface have more energy than others and escape from the liquid
What accelerates the rate of evaporation?
Warmth
Explain why a liquid doesn’t need to boil to turn to gas
Evaporation happens when particles of liquid at the surface have enough kinetic energy to escape
What is the boiling point?
When all particles in a liquid have enough energy to evaporate (and the liquid turns to gas)
What is the significance of zero degrees Celsius and 100 degrees Celsius?
They are the melting and boiling points of pure water
What is the role of evaporation in the water cycle?
It transfers water into the atmosphere
What is condensation?
Loss of latent heat in a gas until it turns into a liquid
What happens when a liquid cools down and reaches the melting point?
The liquid becomes a solid
What happens where a soluble solid is placed into a liquid?
The liquid particles allow the solid particles to mix with them (dissolve)
What is diffusion?
When a soluble solid first is placed in a liquid, the solid particles are in high concentration where liquid meets the solid. Diffusion in the solid particles slowly moving away from each other
What can dissolve into liquids?
Soluble solids and gases
How to dissolved particles move in a liquid?
From a high concentration area (where they first come into contact with the liquid) to a low concentration area
How is water moved around in the oceans?
In currents
What factors affect how fast water evaporates?
Temperature (higher temperature = faster evaporation)
Wind speed (faster winds = more energy = faster evaporation)
Humidity (more humidity = more vapour in the air = slower evaporation)
