Assumptions:
-All matter is made out of particles
-Particles move in constant, random motion.
Physical properties of 3 states
Volume, Shape, Density, Compressibility
Solid: Definite shape, definite volume, cannot be compressed, high density
Liquid: Indefinite shape (take the shape of container), definite volume, cannot be compressed, high density (usually lower than solid)
Gas: Indefinite shape (take the shape of the whole container), indefinite volume, can be compressed, low density
A scientific model is...
-A representation, a prototype or replica of the object/phenomenon that could well explains its physical properties.
-It can be represented using animation or static diagrams.
-Phenomenon includes physical phenomenon like diffusion, dissolving, boiling, condensation evaporation, melting, sublimation etc.
-Physical properties include volume, density, conductivity etc.
MODEL
Solid:
-Particles are packed closely together in an orderly arrangement
-Held together by forces of attraction
-Able to vibrate about their fixed positions but are not free to move amongst each other
Liquid:
-Particles are packed quite close together but not in an orderly arrangement
-Held together by forces of attraction
-Have more energy than solid particles
-Able to move (by rolling and gliding) throughout the liquid
Gas:
-Particles are far apart from each other in a random arrangement
-Have sufficient energy to overcome forces of attraction completely (negligible forces of attraction)
-Able to move freely in all directions
What are assumptions & limitations?
-Assumptions are valid statement to set the parameters for the model to work. Without the assumptions, the principles of the model become invalid or irrelevant.
-Limitations are features of the model not aligned with the actual properties and not able to illustrate the principles of the phenomenon.
Assumptions of the Kinetic Particle Model
-Particles are in constant motion and in random directions.
-Particles possess kinetic energy.
-Forces of attraction exist between particles.
-Heavier particles travel slower than lighter particles.
-Particles do not stick to each other after collision (elastic collision).
-Particles do not stick to each other with the walls of container and bounces back after collision with the walls of container.
-Particles travel in a straight line.
-Particles are small and discrete.
Limitations of the Kinetic Particle Model
-Forces of attraction between particles are not seen in the model. (only for static picture but can be shown clearly on animation)
-Movement of particles in terms of direction and speed may not be accurately captured on static picture but can be shown clearly on animation.
-Distance between particles in model may not be scaled accurately to the actual distance between particles.
ANALOGY TO EXPLAIN KPT
-One example: A rock concert to illustrate interconversion of solid (during concert) to liquid (when concert ends) - (melting)Analogy:
1. During concert, people are closely packed & jumping at fixed positions, just like particle in solid state etc.
2. When concert ends, people are moving disorderly sliding past each other but still closely packed, just like particles in liquid state etc.
Assumptions:
1. People are large in numbers yet small in size relative to entire concert hall.
2. People do not stick to each other upon collision.
3. Each person possesses kinetic energy.
4. Each person moves in constat and random motion.
Limitations:
1. People are of different sizes/masses unlike particles which are of same size/mass of same substance.
2. There is no force of attraction between people unlike particles which consist strong forces of attraction between them.
3. People are not standing in ordered arrangement, unlike particles in solid state in ordered arrangement.
Analogy:
Soccer match to illustrate interconversion of solid to liquid to gas.
-One example: ATM queuing to illustrate diffusion in liquid.
Limitations:
1. People are of different sizes/masses unlike particles which are of same size/mass of same substance.
2. People are in fixed position/regular motion but particles are moving at random.
3. Particles have force of attraction unlike people.
-One example: Comparing animals in cage and wildlife to illustrate sublimation.
Analogy:
Animals are held in fixed position and orderly arrangement, packed closely together.
Animals in wildlife are moving randomly just like the particles in liquid.
Assumptions:
Animals do not stick together upon collision.
Animals are in constant motion.
Animals possess kinetic energy.
Limitations:
No force of attraction between animals.
Animals may not be moving randomly in wildlife.
Animals are of different sizes.
Kinetic Particles Theory
All matter are made up of tiny discrete particles.The tiny particles are in constant random motion.
These particles in motion have kinetic energy.
Higher the temperature, faster the movement of these particles.
Models explain the differences among solids, liquids and gases.
Particulate Model of Matter
-Explains the change of states
-Matter can change easily from one state to another
Melting
-Solid particles gain energy when heated
-Particles vibrate faster
-As temperature increases, vibrations also increase
-Finally, particles are able to overcome the forces that hold them in their fixed positions
melting point: temperature at which solid turns into a liquid
