1. Observation and Measurement  Vocabulary  1. Observation – Using one or more of your senses to collect information  2.Instrument – something that extends the senses beyond their normal limits. Ex:  3. Inference – An interpretation of an observation

2.  4. Classification – grouping similar objects or observations to make them more meaningful  5. Measurement – expressing an observation more precisely using numbers  6. Length – distance between two points  7. Mass – amount of matter in an object (grams)

3.  8.Time – the duration of an event  9. Volume – the amount of space an object occupies  10. Percent deviation (error) – how far off from the true value a measurement is

6. Density  Density – the amount of material in a given space.  D = mass (g) volume (cm 3 ) volume (cm 3 ) Every pure substance has its own density. Every pure substance has its own density. The size of the sample does not affect density as long as mass and volume both change. The size of the sample does not affect density as long as mass and volume both change.

7. Factors that Affect Density  If the mass stays the same but:  1. volume increases; density decreases  2. Temperature increases; volume increases; density decreases  3. Pressure increases; volume decreases; density increases  *** Volume and density have an inverse or opposite relationship!!

8. Density of Solids, Liquids and Gases  For most substances: Solid = most dense Liquid = in between  Gas = least dense  Not true for water!!!  Water is less dense as a solid than as a liquid!!!  Why???

9. Density Quiz  1. If the mass of a cube is 12 g and the length of one side is 2 cm, what is the density? (show work)  2. The density of liquid water is 1.0g/ml. What is the mass of a sample of water with a volume of 50ml?  3. What is the density of a rock with a mass of 20g and a volume of 4cm 3 ?

10. Change  Most change is cyclic and predictable. Ex: seasons, moon phases, tides  Equilibrium – when two opposing forces are in balance –Static equilibrium – no change occurring –Dynamic equilibrium – opposing changes occur at the same rate  Ex: evaporation and precipitation

11. Cyclic changes

12. Environmental Equilibrium  Large, global balance is not easily upset  Modern technology is making some large changes to the global balance –Ex: deforestation, mining, ozone depletion, global warming –Pollution – anything whose concentration reaches a level that harms the environment

13. Miscellaneous Vocabulary  Hypothesis – a possible explanation that can be tested  Theory – a well tested and widely accepted explanation for observable facts.  Interface – a boundary between two things where energy is exchanged –Ex: boundary between wind and water

14. Density Quiz make-up  1. If the mass of a cube is 10g and the length of one side is 3cm, what is the density? (show work)  2. The density of liquid water is 1.0g/ml. What is the mass of a sample of water with a volume of 20ml?  3. What is the density of a rock with a mass of 40g and a volume of 8cm 3 ?