The Science of Physics

1. The Science of Physics Chapter One

2. What is Φΰσις”? Physics: from the greek word “Φΰσις” ( Physis: meaning nature The study of all the natural sciences Motion through spacetime Matter Gravity Light Energy Force Physicsis the analysis of nature

3. What is Φΰσις”? Pythagoras: Quantitative answers Thales: first to question what makes matter Democritus: Origin of atoms Ptolemy: Nature of the stars Archimedes: Engineering and buoyancy

4. What is Physics? • Physics is the study of the physical world. • It explains how things work and why they do what they do.

5. Models Scientists use models to simplify things For example: Imagine studying the motion of a sailboat from one point to another.

6. Models Ignore things that don’t matter (color, shape, waves, wind, sounds, etc.)

7. Models Treat the boat as a point with no shape, the water as a smooth surface, and wind blowing in only one direction Ignore things that don’t matter (color, shape, waves, wind, sounds, etc.)

8. The Scientific Method • Imagine a police investigation of a car accident. You are the detective. How would you figure out what happened?

9. Step 1: Make observations and collect data • Step 2: Form a Hypothesis (also called an educated guess) - I think this is what happened…. • Step 3: Do experiments to test your hypothesis • Step 4: Revise hypothesis, if necessary, according to experimental data • Step 5: Draw a final conclusion: “This is what happened”

10. The SI System of Measurement (International System) International - used to communicate results to anyone throughout the world. - based on powers of ten Easy Give him 2.54 cm and he’ll take 161 000 cm Give him an inch and he’ll take a mile (cm) 91 61 91 36 24 36

11. The 3 Fundamental units in the SI system : Base Units Fundamental Units • meter (length) • kilogram (mass) • second (time) • meter (length) • gram (mass) • second (time)

12. Measurements • Cannot be just a number. Must have a unit • with the quantity. • Dimension - Description of what kind of quantity is represented by a measurement Three Fundamental or Basic dimensions 1. Length 2. Mass 3. Time

13. Derived Units: Formed by combining fundamental units with multiplication or division. Examples: kg m/s2 m3 m/s m/s2 (newton)

14. Power of 10 SI Prefixes Merry king henry died belly up drinking chocolate malted milk ______ ____ 1 000 000 106 mega M k kilo ______ ____ 1 000 103 hecto ______ ____ 100 102 h deka da ______ ____ 10 101 base unit meter, gram, liter etc ______ ____ 1/10 10-1 0.1 deci d centi c ______ ____ 1/100 10-2 0.01 ______ ____ 1/1000 10-3 0.001 milli m ______ ____ 1/1000 000 10-6 0.000 001 micro m

15. SI Prefixes ______ ____ 1 000 000 106 mega M k kilo ______ ____ 1 000 103 hecto ______ ____ 100 102 h da deka ______ ____ 10 101 base unit meter, gram, liter etc ______ ____ 1/10 10-1 0.1 deci d centi c ______ ____ 1/100 10-2 0.01 ______ ____ 1/1000 10-3 0.001 milli m ______ ____ 1/1000 000 10-6 0.000 001 micro m

16. Conversion: chart method ( step method) Move up the chart one step Move decimal to left or Subtract 1 from exponent kilo to mega Count as 3 steps micro to milli

17. Convert 1,235 g to kg

18. ______ ____ 1 000 000 106 mega M k kilo ______ ____ 1 000 103 hecto ______ ____ 100 102 h da deka ______ ____ 10 101 base unit meter, gram, liter etc Convert 2,230 hm to Mm 3 steps 4 steps up 1 step 4 decimal places left 2,230 hm 0.2230 Mm

19. base unit meter, gram, liter etc ______ ____ 1/10 10-1 0.1 deci d centi c ______ ____ 1/100 10-2 0.01 milli m ______ ____ 1/1000 000 10-6 0.000 001 micro m Convert 5 000 000 000 mg to g 6 steps up 3 steps ______ ____ 1/1000 10-3 0.001 3 steps 6 decimal places left 5 000 000 000 mg 5 000 g

20. ______ ____ 1 000 000 106 mega M k kilo ______ ____ 1 000 103 hecto ______ ____ 100 102 h da deka ______ ____ 10 101 base unit meter, gram, liter etc Convert 1.5 x 108 m to km 3 steps up 1 .5 x 108 m Subtract 3 from exponent 1.5x105 km

22. Convert 0.0123 Mg to dag

23. Convert 54,800 L to mL Convert 0.0123 Mg to dag Convert 150000000 m to km Convert 5,000,000 000 mg to g Convert 2,230 hm to Mm Convert 2,230 hm to Mm Convert 2,230 hm to Mm Convert 2,230 hm to Mm