Physics GCSE P1.1 Notes

Infrared Radiation

• Dark dull surfaces absorb and emit more thermal radiation than silver, shiny surfaces.
• All objects emit and absorb infrared radiation.
• Hotter surfaces emit thermal radiation faster than cooler surfaces.
• Objects are absorbing and emitting thermal radiation at the same time.
• If infrared radiation is emitted faster than it is absorbed, the object cools down.

Kinetic Theory:

• Bonds between particles are strongest in solids and weakest in gases.
• Melting - Solid changes to a liquid. When particles are heated, particles vibrate more vigorously and bonds break and reform so particles can change places.
• Freezing - Liquid cools and changes to a solid.
• Boiling - Liquid changes to a gas when it is heated. The particles break bonds and move around randomly.
• Condensing - Gas cools and changes to a liquid.
• Evaporation: Liquids change to gases at temperatures lower than the boling point. Evaporation is quickest if it is warm ( the particles have more energy to break bonds), if the liquid has a large surface area or it is windy.
• Evaporation - at the surface at low temperatures, Boiling…