Monday, Oct. 5th

Agenda• Collect Ozone Worksheet• Go over Sec 2.1 review• Sec. 2.2: Matter and Energy

– Kinetic theory– States of matter– Changes of state– Laws:

• Conservation of mass• Conservation of energy

• Air pressure demos

Section 2.2Matter and Energy

Kinetic Theory

1.All matter is made of atoms and molecules that act like tiny particles.

2.These tiny particles are always in motion. The higher the temperature, the faster the particles move.

3.At the same temperature, more massive (heavier) particles move slower than less massive (lighter) particles.

3 Common States of Matter

Solid

Liquid

Gas

Solids

• Particles are in a fixed position but can vibrate slightly around a fixed location.

• Particles are held closely together by strong attractions.

• Solids have a rigid structure.

Liquids• Particles are closely packed together, but they

can still slide past one another.

• Attraction between particles not as strong as in a solid.

• Liquids can spread out on their own and will take the shape of the container that they are in.

• A liquid is considered a fluid because it can flow.

Gases• Particles are in constant motion and rarely

stick together. They want to be far apart from each other.

• Gases exert pressure on the container that they are in.

• Gases are considered a fluid because they flow.

Solids, Liquids and GasesProperties

Solid Liquid Gas

-particles in fixed position, close together

-particles vibrate only slightly

-strong attractions between particles

-rigid structure

-particles closely packed

-particles can slide past one another

-attraction not as strong as solid

-takes shape of container

-fluid

-particles in constant motion

-particles very far apart

-exerts pressure on container

-fluid

Which letter represents a:1. solid2. liquid3. gas

What is pressure?

• Pressure is defined as the force exerted per unit area of a surface.

• Gases exert pressure.

• The gas in a balloon is pushing out against the walls of the balloon.

What is viscosity?

• Viscosity is determined by the attraction between particles.

• The stronger the attraction, the more slowly the liquid will flow and the higher the viscosity will be.

• Maple syrup has a higher viscosity than water.

Energy’s Role

• Energy is the ability to change or move matter.

• Energy is transferred in all changes of state.

Changes of State• Evaporation: the change of a substance

from a liquid to a gas– Ex: a dish of water on a windowsill will

evaporate in the sun

• Condensation: the change of a substance from a gas to a liquid– Ex: water molecules in the air condensing on

your glass of soda on a hot, humid day

• Sublimation: the change of a substance from a solid to a gas.– Dry ice, solid carbon dioxide, changes from a

solid into a gas.

Law of Conservation of Mass

Mass cannot be created or destroyed.

Law of Conservation of Energy

Energy cannot be created or destroyed.

Air Pressure Demos

Vacuum pack the students!?

Vacuum pack the students?• Yes, that’s what I said.

• Air pressure is pushing down on us all the time, every day.

• If we evacuate the air in a garbage bag to create a vacuum, we can actually feel the effects of the air pressure on our bodies.

• Who wants to try??