1. Thermal Processes (Priyanka, Eilse, Aqeel,Husen, Emir)
1.1. Radiation
1.1.1. Radiation is the transmission of heat or energy in the form of waves or particles through a medium or space
1.2. Convection
1.2.1. Convection is the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.
1.3. Conduction
1.3.1. Conduction is the transfer of thermal energy (heat) from an end with higher temperature to an end with lower temperature. > It transfers heat via direct molecular collision
1.3.1.1. An area of greater kinetic energy will transfer thermal energy to an area with lower kinetic energy. Higher-speed particles will collide with slower speed particles. The slower-speed particles will increase in kinetic energy as a result.
2. Thermal Properties and temperature (Satya, Abner, Aisyah, Bryan,Harinath Simran, Olivia)
2.1. Thermal Expansion (Abner
2.1.1. Tendency of matter to change its shape, area, and volume in response to a change in temperature.
2.1.1.1. When matter is heated = expands > when heated, particles vibrate faster, forcing each other a little further apart
2.1.1.1.1. Expansion: gas > liquid > solid
2.1.1.1.2. Different materials = different degree of expansion (expansivity)
2.1.1.2. When matter is cooled = contracts
2.2. Measurement of Temperature (Simran)
2.2.1. A physical property that varies with temperature may be used for measurement of temperature.
2.2.1.1. Liquid-in-glass thermometer
2.2.1.1.1. The liquid in a glass bulb expands up a capillary tube when the bulb is heated
2.2.1.2. Thermocouple thermometer
2.2.1.2.1. The temperature difference causes a tiny voltage which makes a current flow. A greater temperature difference gives a greater current.
2.2.1.3. Thermistor thermometer
2.2.1.3.1. Type of resistor used to measure temperature changes, relying on the change in its resistance with changing temperature.
2.2.1.4. Infrared thermometer
2.2.1.4.1. Non-contact thermometer; ability to measure temperature from a distance.
2.2.2. Properties of Thermometers
2.2.2.1. Linearity
2.2.2.1.1. Measures proportionality of change of physical property with the temperature > property: length, resistance, voltage
2.2.2.1.2. Thermometer is linear when temperature readings change proportionally with length of mercury column
2.2.2.2. Sensitivity
2.2.2.2.1. The change in length of mercury column per unit degree change in temperature
2.2.2.3. Range
2.2.2.3.1. The maximum and minimum temperature of thermometers
2.2.2.4. Responsiveness
2.2.2.4.1. The speed at which a reading can be obtained
2.3. Thermal Capacity (Satya and Aisyah)
2.3.1. the amount of heat energy required to make an object increase its temperature by 1ºC, the same applies to when it cools by 1ºC.
2.3.2. The greater the thermal capacity of an object, the more thermal energy is needed to increase its temperature.
2.3.3. Units
2.3.3.1. measured in J/°C or J/K
2.3.4. Depends on
2.3.4.1. mass of object
2.3.4.2. type of material
2.3.5. Formula
2.3.5.1. C = Q /ΔT
2.3.5.1.1. heat capacity = heat absorbed or released / change in temperature
2.3.6. Relationship between heat capacity & mass
2.3.6.1. 𝑪∝𝒎
2.3.6.1.1. k = c /m
2.4. Melting and Boiling (Bryan)
2.4.1. Boiling:
2.4.1.1. Occurs at boiling point, the point at which molecules are able to overcome the atmospheric pressure and escape into the atmosphere.
2.4.1.1.1. When atmospheric pressure is less, boiling point decreases.
2.4.1.2. Occurs throughout the boiling liquid, unlike evaporation that only occurs at the surface.
2.4.1.3. Change from liquid to gas
2.4.1.4. The energy absorbed by a liquid before reaching boiling point is called latent heat of vaporization.
2.4.1.4.1. The energy absorbed is used to overcome the attractive forces between the particles, so that they can separate and turn into the gaseous state.
2.4.2. Melting:
2.4.2.1. Change from solid to liquid
2.4.2.2. Occurs when there is a rise in temperature.
2.4.2.3. The energy absorbed by a solid before melting is called the latent heat of fusion.
2.4.2.3.1. The energy is needed to separate the particles so that a liquid can be formed.
2.5. Specific Heat Capacity (Satya)
2.5.1. The specific heat capacity of a material is the energy required to raise one kilogram of the material by one degree Celsius in ºC.
2.5.2. (FORMULA) change in thermal energy = mass × specific heat capacity × temperature change.
3. Simple Kinetic Molecular Model of Matter (Umar,Adam, Jun Keat, Giselle, zulaykha )
3.1. Kinetic Theory of Matter
3.1.1. Consists of large number of small particles, (atoms or molecules)
3.1.2. Separation between particles are caused by intermolecular forces
3.1.2.1. - the closer they are, the stronger their forces of attraction - the further they are, the weaker their forces of attraction
3.1.3. Particles are in constant motion, colliding and exchanging energy
3.1.3.1. The temperature of a matter is the result of the average kinetic energy of particles
3.2. Brownian Motion
3.2.1. The tiny particles and molecules in atoms are too small for us to see, but they can be seen by 'scientific eyes':
3.2.2. Set up an experiment: 1. a small glass cell filled with smoke 2. a lamp to shine light through the cell 3. view the smoke through a microscope 4. you should see smoke particles constantly moving and changing direction
3.2.2.1. We see the smoke particles by reflected light; their random movement is called Brownian Motion > caused by collisions of the fast-moving air molecules in a container
3.2.2.2. The imbalance, and direction of the net force , changes rapidly in this random movement
3.2.2.3. Looks like a lot of this movements
3.3. State of Matter
3.3.1. Diagram
3.3.2. Liquid= no fixed shape, fixed volume, (Azuzay)
3.3.3. Solid = fixed shape/volume (Zulaykha)
3.3.3.1. Particles vibrate in fixed positions and are tightly packed. It is difficult to change shape and not free moving.(Zulaykha)
3.3.4. Gas = no fixed shape/volume (Zulaykha)
3.4. Energy of Particles
3.4.1. Particles have kinetic energy (Ek) because of their constant motion
3.4.2. Particles also have potential energy (Ep) because their motion keeps them separated, opposing the forces of attraction
3.4.2.1. Internal Energy = Ek + Ep
3.4.2.2. Thermal Energy is the total amount of internal energy of each particle in an object
3.4.2.2.1. eg: when thermal energy of a substance increases, particles move faster (a change in thermal energy could cause a change in phase)
3.5. Molecular Model
3.5.1. liquid= particles could slide over each other, quite close to each other and have more energy then solid's (Azuzay)
3.5.2. solid= particles are closely packed, can only vibrate tro and for and have the least amount of energy (Azuzay)
3.5.3. gas= particles are much more spaced as there is not intermolecular force holding them and have the most energy. (Azuzay)
3.5.3.1. Particles are free moving and takes the shape of the container. It also has the lowest density.(Zulaykha)
3.6. Evaporation
3.6.1. Evaporation happens because some particles in liquid move faster than others. The faster ones near the surface have enough energy to escape as a gas
3.6.1.1. Evaporation increase rapidly when
3.6.1.1.1. The temperature is increased
3.6.1.1.2. Surface area of the liquid is larger
3.6.1.1.3. Wind is blowing over the surface
3.6.1.1.4. Humidity is reduced
3.7. Pressure Change
3.7.1. pressure is a force thats exerted on an object.
3.7.1.1. atmosphere= change in pressure at the atmosphere is cause by change in air density, warmer air is less dense.(Azuzay)
3.7.1.2. water = As depth increases the pressure increases because the object gets the full weight of the water. (Azuzay)