An Introduction to Fluids…..
Fluids are substances that FLOW
The properties of fluids include density, buoyancy, viscosity, pressure, and temperature.
Kinetic Molecular Theory:
1) All matter is made out of particles (atoms or molecules)
2) Particles are in constant motion (moving fast or slow and bumping into one another)
3) There are laws of attraction that explain their movement.
A law is a summary of observations, and a theory is an explanation of those observations. The individual gas laws give us a set of mathematical tools to help predict the behavior of gases under specific conditions of pressure, temperature, volume and number of moles of gas. They do not, however, explain why gases behave the way they do. Kinetic molecular theory is an attempt to explain some of the bulk properties of matter by describing how particles interact with one another. Kinetic molecular theory can help us understand how and why the gas laws work and to predict when the gas laws won’t work.
Daniel Bernoulli started kinetic molecular theory in 1738 when he proposed a thought model consistent with Boyle’s Law in an attempt to explain how gases exert pressure. Clausius refined the theory in the mid-1800s.
The Assumptions of Kinetic Molecular Theory:
In order to explain how gases behave we can make the following assumptions:
- A gas is composed of particles in constant motion.
- The average kinetic energy depends on temperature, the higher the temperature, the higher the kinetic energy and the faster the particles are moving.
- Compared to the space through which they travel, the particles that make up the gas are so small that their volume can be ignored.
- The individual particles are neither attracted to one another nor do they repel one another.
- When particles collide with one another (or the walls of the container) they bounce rather than stick. These collisions are elastic; if one particle gains kinetic energy another loses kinetic energy so that the average remains constant.