Science Focus Topic 3 Notes: The Particle Model, Temperature & Thermal Energy | Print |
Particle Model:




Particles are closely packed together

Particles can slip past each other

Particles have lots of space between them

The Particle Model of Matter is a scientific description of the tiny particles that make up all things. The key elements in this model are:

All substances are made of tiny particles too small to be seen
The particles are always in motion
The particles have spaces between them

Temperature and the Particle Model

When heat is added to a substance, the particles move faster. When heat is lost from a substance the particles move slower.
The motion of the particles increases when the temperature increases.
The motion of the particles decrease when the temperature decreases

Temperature indicates the average energy (speed) of the particles in motion in a substance.

What is Energy?

Energy is the measure of a substance's ability to do work - or cause changes.
There are two important elements that occur:
Changes happen when there is a difference of energy (every useful energy system has a high-energy source that powers the changes)

Energy is always transferred in the same direction: from a high-energy source (hot) to something of lower energy (cold).

Thermal Energy and Temperature Changes

When heat is transferred in a space the average energy of the particles - the temperature of the substance - is affected, by increasing or decreasing. The change in temperature depends on the number of particles affected.

What Energy is ? and is NOT

Energy is not a substance. It cannot be seen, weighed or take up space. Energy is a condition or quality that a substance has. Energy is a property or quality of an object or substance that gives it the ability to move, do work or cause change.

Law of Conservation of Energy states that:
Energy cannot be created or destroyed.
It can only be transformed from one type to another,
or passed from one object, or substance to another.

Topic Review p. 208
Wrap-Up (Topics 1-3) p. 209