1. States of Matter January 4, 2016 6 th grade Chapter 4.1

2. States of Matter Which ones do you remember?

3. Most Common States of Matter Solid: Definite shape, definite volume Liquid: Indefinite shape, definite volume Gas: Indefinite shape, indefinite volume (depends on pressure) There are other states of matter like plasma, superfluid, strange matter, etc but they’re rare outside of a lab

4. States of Matter

5. Solids All matter is made of molecules, and molecules are always moving Molecules in solids are close together and don’t move much: more like shaking This lets the solid stay in the shape you put it in Shape can be crystalline or amorphous Crystalline: regular, repeating pattern, melts at 1 temp Amorphous: random or imperfect pattern, melts over a range of temperatures

6. Examples CrystallineAmorphous

7. Liquids Molecules in liquids are close together, but they move around a lot Liquids fill the bottom of their container as much as possible Things like surface tension and viscosity or cohesion might change how long it takes to do that Some things that seem like solids behave like liquids if you leave them long enough o Dough o Pitch drop experiment

8. Properties of Liquids Fluid: another word for a liquid. A substance that flows. Surface tension: inward force/pull of molecules in a liquid trying to give it the smallest surface area Sphere is the best volume : surface area, so high surface tension = closer to sphere shape Viscosity: how well a liquid resists flowing. If it’s sticky, it’s viscous/high viscosity. If it’s easy to pour, it’s not viscous/low viscosity

9. Which property is being shown?

10. Gases Molecules in a gas spread out as much as possible – they fill the entire container Gas molecules move a lot compared to liquids or solids Want to know the volume, pressure, and temperature of a gas – changing one of these will change the other two

11. Review TemperatureVolume

12. Pressure Since gas molecules fill the entire container and are constantly moving, they are constantly banging into the sides of their container This is called pressure Pressure can be used for liquids & solids, but then you have to worry about gravity too