Welcome to Physical Science in SCI 204 Mrs. Melissa Harris

Ch 1-Science skills Science vs Technology SCIENCE= system of knowledge & the methods you use to find knowledge TECHNOLOGY= the application of scientific knowledge to improve the quality of life Which came first-science or technology?

What is Physical Science? PHYSICS= study of matter & energy & the interactions between the two through forces & motion

CHEMISTRY= study of the composition (what matter is made up of), structure, properties (what matter is like & how it behaves), & reactions of matter

SCIENTIFIC THEORY versus SCIENTIFIC LAW Theory=an Explanation based on many observations supported by experimental results (explains why things work the way that they do)

SCIENTIFIC THEORY versus SCIENTIFIC LAW Law=“rule of nature” Evidence summed up by related observations & experimental results to describe a pattern found in nature.

What is the SCIENTIFIC METHOD? an organized plan for gathering, organizing, & communicating information

STEPS 1) OBSERVATION= using senses to gather info 2) PROBLEM= what do you want to know? 3) HYPOTHESIS= educated guess 4) EXPERIMENT= way to test hypothesis

STEPS in the experiment –M–Manipulated variable (Independent)= causes a change in another –R–Responding variable (Dependent)= the variable that changes in response to the manipulated variable

Controlled Experiment= a standard for comparison, hold a variable constant (does not change)

STEPS 5) ANAYLZE DATA= in words, charts, &/or graphs 6) CONCLUSION= Accept or Reject hypothesis, what you learn/discover

Analyze Data w/ Graphs Graph= a visual display of info –Pie Graphs= shows how some fixed quantities are broken down into parts *must equal 100% –Bar Graphs= show info collected by counting

Analyze Data w/ Graphs –Line Graphs= shows changes occurring over time Direct proportion= ratio of 2 variables is constant, both increase or decrease Inverse (Indirect) proportion= as one variable increases the other decreases, vice versa

Graphs

Bart believes that mice exposed to microwaves will become extra strong. He decides to perform this experiment by placing 10 mice in a microwave for 10 seconds. He compared these 10 mice to another 10 mice that had not been exposed. His test consisted of a heavy block of wood that blocked the mouse food. He found that 8 out of 10 of the microwaved mice were able to push the block away. 7 out of 10 of the non-microwaved mice were able to do the same. Identify the- 1. Control Group Mice not exposed. 2. Independent Variable Amount of microwave exposure 3. Dependent Variable Ability to move the wood block 4. What should Bart's conclusion be? Microwaves have no influence on strength of mice. 5. How could Bart's experiment be improved? Change the activity measured, more experimental groups, etc…

STAR Questions What is the Manipulated variable? causes a change in another What are observations? Using 5 senses to gather info What is a constant? –Variable that does not change during the experiment What is a control? –Standard for comparison during an experiment

Measurements Why measure? Why units?

Length the distance between two points SI unit is meter (m) Instrument used is ruler or meterstick

Now let’s convert cm into m, cm to mm, mm to m, and cm to dm

Volume = the amount of space occupied by an object Solids Liquids Tool used SI Units Ruler Graduated cylinder Multiply LXWXH cm 3 (cubic centimeters) mL (milliliters) Derived unit is a combo of units

10 cm 9 cm 8 cm Volume of regular object length x width x height _____ X _____ X _____ = _____

Volume of irregularly shaped objects estingmain1.htm water displacement method Amount of H 2 O with object = ______ About of H 2 O without object = ______ Difference = Volume = ______ mL Menicus=curved surface of liquid)

Mass Amount of matter in an object SI unit is Kg (g if smaller) Instrument is a balance

SI= International System of Units used worldwide by scientists to communicate, based on multiples of ten

CONVERSIONS K, h, da, base unit, d, c, m K____ has dirty underwear don’t check mine Convert 5mL to L Move decimal 3 places to the left, so 5mL=0.005L

KILO 1000 Units HECTO 100 Units DEKA 10 Units DECI 0.1 Unit CENTI 0.01 Unit MILLI Unit Meters Liters Grams Ladder Method How do you use the “ ladder ” method? 1 st – Determine your starting point. 2 nd – Count the “ jumps ” to your ending point. 3 rd – Move the decimal the same number of jumps in the same direction. 4 km = _________ m How many jumps does it take? Starting Point Ending Point 4. 1 __. 2 3 = 4000 m

Try these conversions using the ladder method mg = _______ g 1 L = _______ mL160 cm = _______ mm 14 km = _______ m109 g = _______ kg 250 m = _______ km Conversion Practice Compare using, or =. 56 cm 6 m 7 g 698 mg

Write the correct abbreviation for each metric unit. 1) Kilogram _____ 4) Milliliter _____ 7) Kilometer _____ 2) Meter _____ 5) Millimeter _____ 8) Centimeter _____ 3) Gram _____ 6) Liter _____ 9) Milligram _____ Try these conversions, using the ladder method. 10) 2000 mg = _______ g 15) 5 L = _______ mL 20) 16 cm = _______ mm 11) 104 km = _______ m 16) 198 g = _______ kg 21) 2500 m = _______ km 12) 480 cm = _____ m 17) 75 mL = _____ L 22) 65 g = _____ mg 13) 5.6 kg = _____ g 18) 50 cm = _____ m 23) 6.3 cm = _____ mm 14) 8 mm = _____ cm 19) 5.6 m = _____ cm 24) 120 mg = _____ g Metric Conversion Challenge

Compare using, or =. 25) 63 cm 6 m 27) 5 g 508 mg 29) 1,500 mL 1.5 L 26) 536 cm 53.6 dm 28) 43 mg 5 g 30) 3.6 m 36 cm

TIME Interval between two events SI unit is second (s) Instrument is stopwatch or CPO Timer

Temperature How hot/cold something is SI unit is Kelvin (K) *0K = -273 o C (Absolute Zero) Conversion – to change o C to Kelvin, add 273 & vice versa Instrument is the thermometer

Density Ratio of Mass per unit Volume D M V SI UNITS Liquid = g/mL Solid = g/cm 3 D=? V=5mL M=10g D=50g/cm 3 V=? M=10g

What does the layering indicate? Assuming each liquid has a given volume of 20mL. What is the mass of each of the substances? Water Mercury, _______ g/mL Gasoline Gold Ethanol, _______ g/mL

GUESS G= Given, identify the given information U= Unknown, identify the unknown, what are you trying to solve for? E= Equation, what equation should you use to solve the problem? S= Substitute the numbers in for the letters in the equation S= Solve, plug in the calculator, chug get an answer….don’t forget the units!

The density of Al is 2.70 g/cm 3. A piece of Al has a volume of 45cm 3. What is the mass of this piece of Al foil?

STAR Questions What is the distance between 2 points? –Length What is the tool used to measure the volume of a liquid? Units? –Graduated Cylinder mL What is the equation to solve for density? –D=mass / volume