1. Introduction to Science

2. Theories & Laws ► Scientific Theory  Explanation that has been tested by repeated observations (experiments)  Constantly questioned and must pass three tests ► 1) Theories must explain observations simply & clearly ► 2) Experiments that illustrate the theory must be repeatable ► 3) You must be able to predict from a theory

3. ► Scientific law  States a repeated observation about nature  *** Theories and Laws are NOT absolute ***

4. Measurement ► Use a standard system of units called the SI units ► A decimal system (0.0) that uses the number 10 as a base unit

5. ► SI prefixes are use for very large and very small measurements ► They are all multiples of ten

6. Measurement ► Length  SI unit is the meter (m)  Divided into 100 equal parts called the centimeter (cm)  One cm would be 1/100 of 1m  One millimeter (mm) is 1/10 of 1cm  One kilometer = 1000 m

7. ► Mass  The amount of matter in an object  The mass is ALWAYS the same no matter where the object is in the Universe  SI unit is the kilogram (kg)  (how many grams?)

8. ► Weight  Measure of the gravitational force on an object  Weight will vary (weight on moon is 1/6 th of Earth)  The SI unit is the Newton (n)

9. ► Area  Require a combination of SI units  Area is the amount of surface included within a set of boundaries (length x width)  Area uses the square units of length m 2

10. ► Volume  Volume is the amount of space occupied by an object  The unit of volume is the cubic meter m 3  Fluids use milliliter (mL) or liters (L)  1 cm 3 = 1 mL

11. ► Density  The amount of matter that occupies a given space  Found by dividing the mass by its volume  Expressed by: ► Grams per cubic centimeter (g/cm 3 ) ► Grams per milliliter (g/mL) ► Kilograms per cubic meter (kg/m 3 )

12. ► Time  Interval between two events  SI unit is the second

13. ► Temperature  Measure of the average kinetic energy of the particles in a material  Particles that vibrate quickly have higher temperatures  Scientists often uses Celsius (C) ► Water freezes at 0C and boils at 100C ► Conversion to F = multiply by 1.8 and add 32

14. ► Temperature Contd.  SI unit for temperature is Kelvin (K)  The coldest possible temperature is absolute zero = 0K or -273C  The difference is to simply subtract 273 from the K temperature to get the Celsius temperature

15. ► More practice  Conversion of F to C --> ► (F-32) x 5/9 or (F-32) /1.8

16. Scientific Notation ► Some numbers are too small or too large to write out ► Scientific notation allows the number to be expressed as a value between 1 and 10 multiplied by a power of 10 ► The power of 10 tells you the number of places the decimal point must be shifted so that only one digit remains to the left of the decimal point

17. ► If the decimal point is to be shifted to the left, then the exponent of 10 is positive ► Examples:  The number of grains of sand on Earth = 4,000,000,000,000,000,000,000.00  Can be written as 4 x 10 21  Earth’s mass is 5,974,200,000,000,000,000,000,000  Can be written as 5.9742 x 10 24

18. ► If the decimal must be shifted toward the right, then the exponent will be negative ► Example:  The diameter of an atom is 0.0000000001 m  Can be written as 1 x 10 -10