Introduction to Physical Science: The Metric System and Scientific Method

1. Unit 1 Introduction to Physical Science

2. The metric system • Used around the world • Easy to convert units • Easy(math by 10’s) • American money system is metric

3. SI (Le Système international d’unités) unit of measure • Base units

4. Derived Units • Derived Units – a combination of base units • Area – m2 (square meter) • Volume – m3 (cubic meter) • Density – kg/m3 (kilogram per cubic meter) • Pressure – Pa (Pascal = kg/m· s2)

5. Metric Pre-fixes

6. Practice • Convert: • 9 ms to s • 12 km to m • 13 kL to nL

7. Scientific Notation • When a number gets VERY big or VERY small we use scientific notation to write them down. • It is a written as a number from 1 and <10 followed by a power of ten. • Big numbers will have a POSITIVE power (decimal moves left) Example: 300,000,000

8. Scientific Notation • When a number gets VERY big or VERY small we use scientific notation to write them down. • It is a written as a number from 1 and <10 followed by a power of ten. • Small numbers will have a NEGATIVE number (decimal moves right) Example 0.00086

9. Branches of Science • Science: A system of knowledge and methods used to find that knowledge.

11. Scientific Method/ Approach • A step-by-step process that scientist use to do their research and verify the work of others.

12. Scientific Method/Approach • Observation – gathering data Example: Do you get wetter running or walking through the rain? • Question (leads to) hypothesis – an explanation (guess) for the observation (MUST BE TESTABLE) Example: If you run in the rain (so the faster your speed), then the drier you will stay.

13. Scientific Method/Approach • Experiment – tests the hypothesis • Example: • Have two people go 100 meters in rain – 1 walk vs. 1 running • Variable: Any factor that can change • Independent (manipulative) variable – causes change in another variable • Example – Running vs. Walking • Dependent (responding) variable – changes because of the independent variable • Example – Water accumulated • Controlled variable – variable that is kept CONSTANT (doesn’t change) • Example – Distance, height, weight, rain, clothing

14. Scientific Method/ approach • Analyze/ Conclude – based on the results • Example • Walked = 130 grams of water Vs. Ran = 217grams of water • Walking in the rain will keep you about 40% drier • If it supports the hypothesis • More experiments/ tests • If it disproves the hypothesis • Revise hypothesis and retest/re-experiment

15. Scientific Law vs. Scientific Theory • Theory – an explanation that has been supported MANY times by other scientist • Example: Germ Theory

16. Scientific Law vs. Scientific Theory • Law – Something that has been observed to happen without fail (ALWAYS) • There may not be an explanation for the event (that’s what theories are for!) • Example: Law of gravity

17. Scientific Model • Models – make it easier to understand things that are too hard to observe directly (too big or too small) • Physical – these can help you physically see how something might work or look like • Mathematical – contain mathematical equations and graphs • Conceptual – uses systems of ideas or comparisons to help illustrate or explain things

18. Presenting Scientific Data • Data Tables • Use a ruler for straight edges • Include labels NOTE: if using a measured value include the unit!

19. Presenting Scientific Data • Graphs • ALL graphs should have a TITLE • General rule of thumb is to make all graphs: NEAT, TIDY, AND COLORFUL! Bar/Line Graphs • Label BOTH axis (label AND unit) • If applicable connect points (line graph ONLY) • USE ENTIRE SHEET OF GRAPH PAPER!!!! • USE A RULER

20. Presenting Scientific Data • Graphs • ALL graphs should have a TITLE • General rule of thumb is to make all graphs: NEAT, TIDY, AND COLORFUL! Pie Charts • To find angle take decimal form of percent and multiply by 360 • Each wedge/slice should have a percent AND label • USE A RULER AND A PROTRACTOR