SCIENCE LIGHT, HEAT, SOUND TEST Flashcards
Heat
A form of energy that can be transferred through solids, liquids, and gases.
Particle model
The particle model explains the transfer of heat through solids, liquids and gases. In the particle model of matter, atoms are represented as small, hard balls.
Solids
- Particles are closely packed together,
- Vibrate on the spot
- Keep the shape of the substance
Liquids
- Particles are packed closely together
- Vibrates and free to move over each other particle
Gases
- Particles are not bound together
-Are free to move in straight lines until they collide with other particles
Heating Substances
Heating substances add energy to their particles, which can be stored as potential energy. The more heat, the faster the particles will move and the more the particles will spread out and expand, and vice versa for when the heat is lost.
Heat Transfer
Heat can flow from areas of higher to areas of lower temperature. The process of heat transfer can occur in three different ways:
- Convection
- Conduction
- Radiation
Convection
Convection is the transfer of heat in a gas or liquid in which the warmer parts move up and the cooler parts move down
- Cannot happen in a solid because particles can only vibrate and cannot move freely like they do in a liquid or gas
- Hot air is less dense than cool air
An example of convection is an air conditioner releasing hot air. After a period of time, the hot air will rise to the top of the room and only cooler, denser air stays at the bottom.
Conduction
Conduction is a method of heat transfer in which heat moves through the direct physical contact between matter or particles of matter.
An example of conduction is when you hold an ice cube and it melts. The heat from your hand has transferred to the ice cube. While your skin’s temperature lowers, the ice cube’s temperature rises. This demonstrates heat flowing from a high temperature (your hand) to a low temperature (the ice block).
Conductors
Conductors are substances that transfer heat easily. Metal is an example of a good conductor.
Insulators
Insulators are substances that are poor conductors of heat. Examples of insulators are plastic and wood.
Radiation
Movement of heat in the form of electromagnetic waves, which can travel through a vacuum.
- Transmits heat through invisible waves that travel at the speed of light.
- Movement of heat is in the form of electromagnetic waves that travel through space (e.g. radio waves, x-rays)
An example of radiation is when you go outside into the sunlight, you can feel the heat radiating from the sun. Heat has travelled through empty space between the Sun and the Earth to reach you.
Use the particle model to explain the convection and conduction of heat.
In CONVECTION, heat energy is carried by the movement of particles of matter. In CONDUCTION, heat is transferred by particles vibrating.
Sound
Sound is produced when something vibrates, moving back and forth very quickly. Sound travels through vibrating particles. This means that sound can pass through solids, liquids and gases, at least in some capacity.
Compression and Rarefractions
When something vibrates, it passes the vibrations in its surroundings e.g. air. These vibrations create regions of space in which the air particles are bunched together and regions in which they are more spread out. The bunched up areas are called compressions and the spread out areas are called rarefractions.
