Ch. 4 States of Matter

1. Ch. 4 States of Matter • States of Matter • Solid • Liquid • Gas • Solid – matter with a definite shape and volume. • Particles (atoms) within a solid are in constant motion while maintaining a shape and volume. • Types of Solids • Crystalline Solids are mostly arranged in a repeated three-dimensional pattern. We will see this when we study minerals and rocks. • Amorphous Solids – arranged together without forming patterns or crystallization.

2. Liquid – matter that has a definite volume but no definite shape. • Particles (atoms) are constantly moving to create a constant volume but can not maintain its own shape. • Liquid Characteristics • Viscosity – resistance to flow; high viscosity does not flow easily such as honey while water has lower viscosity. • Surface Tension – ability of the particles of liquids to support (float) objects on its surface. • Gases – matter that has no definite volume or shape. • Particles (atoms) move so freely that they can not maintain any signs of volume or shape.

3. Change of States of Matter • What is the cause of change in matter? The change in energy • Energy is the ability to do work or cause change; this the ability to cause the particles of matter to be in motion which is kinetic energy. • Kinetic energy vs. Potential energy • Kinetic energy is energy in motion. • Potential energy is stored energy due to its state of matter. • Kinetic energy and potential energy of matter is called thermal energy. This thermal energy depends on the number of particles of substance and how fast are these particles moving. • Particles with more kinetic energy moves faster and less when the particles slow down.

4. Temperature vs. Heat • Temperature is the average kinetic energy of the individual particles of a given substance. This measures on average how fast or slow are the particles moving within a substance. • Heat is the amount of thermal energy is moving from one substance to another. • Example: You place a heating pad on your sore back. You are adding heat to your back. The cause is the heating pad is transferring thermal energy to your back. Will this increase the temperature in your back? • Specific Heat – is the amount thermal heat (energy) needed to increase the temperature of a substance. Some substances like metal low specific heat which means they heat up and cool down quickly.

5. Changes of state of matter between solid and liquid • Melting • Freezing • Changes of state of matter between liquid and gas • Vaporization (Boiling) • Condensation • Changes of state of matter between solid and gas • Sublimation – dry ice

6. Behavior of Fluids • Pressure – force exerted on a surface divided by the total area over which the force is exerted. • Balloon • Pressure = force/area; Newton/square meter = N/m2 • Atmospheric Pressure – pressure of air on you body and the environment. This is measured in kPa • Changes in Gas Pressure • Volume – What is the affect on pressure if you decrease the volume? • Temperature – What is the affect on pressure if you increase the temperature

7. Float vs. Sink • Buoyant force is the pressure that allows an object to float or not. • If the buoyant force is greater than weight of the object then the object will float. • What causes buoyant force? Density of the two substances (object and the liquid) • Density is the mass of an object divided by volume • Density = mass /volume or grams/cubic meter • If an object has more density then the liquid it will sink.

8. Pascal’s Principle – relationship between force and pressure; when force is applied to a confined fluid, an increase in pressure is transmitted equally to all parts of the fluid. • Hydraulic System of machinery follows this principle • Heart also follows this principle.