1. Solids, Liquids, and Gases

2. Kinetic Theory
The kinetic theory is an explanation of how particles in matter behave.
All matter is composed of small particles (atoms, molecules, ions)
These particles are in constant, random motion.
These particles are colliding with each other and the walls of their container.

3. Cool Science

4. Thermal Energy All objects have energy
Potential Energy – from the bonds that hold the substance together
Kinetic Energy – from the motion or vibration of the atoms and molecules
The total energy of a material’s particles is called the thermal energy.

5. Thermal Energy
More energy = more motion = higher temperature

6. Temperature
Temperature measures the average kinetic energy of the particles in a substance.

7. Solids Particles are closely packed together
Particles have different geometric arrangements.
These arrangements determine the physical and chemical properties.

8. Carbon

9. Liquids
Particles have enough energy to break free from the geometric arrangement.
Substance flows and takes the shape of its container.
Melting point – temperature at which a substance goes from solid to liquid
Heat of Fusion – energy required to reach the melting point

10. Gases
Particles have enough energy to escape the attractive force of the other molecules.
Expand to take the size and shape of their container
Heat of Vaporization – amount of energy required for a liquid to become a gas
Diffusion – spreading out of gas molecules to fill their container.

11. Boiling
Boiling point – temperature at which a substance goes from a liquid to a gas.
Liquids stay in their container because of air pressure.
Liquids boil because the internal pressure of the liquid becomes equal to the pressure of the air and the molecules are allowed to escape.

12. Heating Curves Graph that shows the states of matter of a substance.
As a solid melts and a liquid vaporizes the temperature remains constant.
The temperature increases after the phase change has happened.

13. Heating Curves

14. Plasmas
High temperature gas with positively and negatively charged particles.
Found in lightning and neon signs

15. Thermal Expansion
Increase in the size of a substance when it is heated.
Occurs in most solids, liquids, and gases.
Water is the exception.

16. Weird Things
Some substances do not react as expected when changing states.
Amorphous Solids
Lack the geometric pattern of other solids
Glass and Plastic
No definite melting/boiling point
Liquid Crystals
Keep their geometric arrangement when liquid
Liquid Crystal Displays
Non-Newtonian Substances
Acts as different states based on certain conditions

17. Buoyancy
The ability of a fluid (liquid or gas) to exert an upward force on an object immersed in it.
If the buoyant force is equal to the weight of the object, the object will float.
If the buoyant force is less than the weight of the object, the object will sink.

18. Archimedes’ Principle
The buoyant force on an object is equal to the weight of the water displaced.

19. Density Mass ÷ Volume More dense objects sink Less dense objects float
To increase the density you can:
Decrease the volume
Increase the mass
To decrease the density you can:
Increase the volume
Decrease the mass

20. Pressure Pressure = Force / Area To increase the pressure:
Increase the force
Decrease the area
To decrease the pressure:
Decrease the force
Increase the area

21. Pascal’s Principle Pressure is constant throughout a fluid
In simple terms, pressure is the same in a fluid.
Force 1 / Area 1 = Force 2 / Area 2
Hydraulic Lifts

22. Bernoulli’s Principle
As the velocity of a fluid increases, the pressure decreases.
Fast air = less pressure
Slow air = more pressure
Airplane wings are designed so that the air moves faster on the top. That means there is a small pressure pushing down and a bigger pressure pushing up. The airplane is then able to fly.

23. Viscosity The resistance of a fluid to flow
Low viscosity = flows easily (water, milk)
High viscosity = does not flow easily (syrup, ketchup)

24. Assignment Section 2 Reinforcement
On the back, answer these questions:
What are two opposing forces that act on an object floating in water?
Why do helium balloons float and non helium balloons sink?
Why are roofs lifted off houses during tornados?
How is it possible for a heavy boat to float on water?