The Nature of Science  Defining Science  Problem-Solving  Scientific Method  Experimental Design

A. Defining Science  Pure Science  research that adds to the body of scientific knowledge  has no practical use  Applied Science (Technology)  the practical application of scientific knowledge

A. Defining Science PURE  human genetics  polymer science  atomic theory  study of the human ear APPLIED  DNA fingerprinting  Lycra ® spandex  nuclear weapons  hearing aids

A. Defining Science  Life Science  the study of living organisms  Earth Science  the study of Earth and space  Physical Science  the study of matter and energy  chemistry & physics

B. Problem-Solving 1. Identify the problem.  What do you know?  What do you need to know? 2. Plan a strategy.  Look for patterns.  Break the problem into smaller steps.  Develop a model.

B. Problem-Solving 3. Execute your plan. 4. Evaluate your results.  Did you solve the problem?  Is your answer reasonable? Identify - Plan - Execute - Evaluate

C. Scientific Method  Hypothesis - testable prediction  Theory - explanation of “why”  based on many observations & experimental results  Scientific Law - prediction of “what”  describes a pattern in nature

C. Scientific Method Theories and laws are well-accepted by scientists, but... They are revised when new information is discovered. THEY ARE NOT SET IN STONE!

C. Scientific Method 1. Determine the problem. 2. Form a hypothesis. 3. Test your hypothesis. 4. Analyze the results/data. 5. Draw conclusions.

C. Scientific Method 1. Determine the problem. When the Titanic sank, what happened to the water level on shore? 2. Make a hypothesis. The water level rose. The water level dropped. The water level stayed the same.

C. Scientific Method 3. Test your hypothesis. How could we test our hypothesis? 4. Analyze the results. What happened during our test? 5. Draw conclusions. Was our hypothesis correct? Is further testing necessary?

D. Experimental Design  Experiment - organized procedure for testing a hypothesis  Key Components:  Control - standard for comparison  Single variable - keep other factors constant  Repeated trials - for reliability

D. Experimental Design  Types of Variables  Independent Variable  adjusted by the experimenter  what you vary  Dependent Variable  changes in response to the indep. variable  what you measure

D. Experimental Design  Hypothesis: Storing popcorn in the freezer makes it pop better.  Control: Popcorn stored at room temp.

D. Experimental Design  Single variable: Storage temperature  Constants: Popcorn brand Freshness Storage time Popper

D. Experimental Design  Independent Variable: Storage temperature  Dependent Variable: Number of unpopped kernels

Measurement I. Units of Measurement  Number vs. Quantity  SI Base Units & Prefixes  Derived Units  Density Calculations

A. Number vs. Quantity  Quantity - number + unit UNITS MATTER!!

B. SI Units QuantityBase UnitSymbol Length Mass Time Temp meter kilogram second kelvin m kg s K CurrentampereA

B. SI Units mega-M10 6 deci-d10 -1 centi-c10 -2 milli-m10 -3 PrefixSymbolFactor micro-  nano-n10 -9 pico-p kilo-k10 3

C. Derived Units  Combination of base units.  Volume - length  length  length 1 cm 3 = 1 mL 1 dm 3 = 1 L  Density - mass per unit volume (g/cm 3 ) D = MVMV D M V

D. Density  An object has a volume of 825 cm 3 and a density of 13.6 g/cm 3. Find its mass. GIVEN: V = 825 cm 3 D = 13.6 g/cm 3 M = ? WORK : M = DV M = (13.6 g/cm 3 )(825cm 3 ) M = 11,220 g D M V

D. Density 1) A liquid has a density of 0.87 g/mL. What volume is occupied by 25 g of the liquid? GIVEN: D = 0.87 g/mL V = ? M = 25 g D M V WORK : V = M D V = 25 g 0.87 g/mL V = 28.7 mL

D. Density 2) You have a sample with a mass of 620 g & a volume of 753 cm 3. Find density. GIVEN: M = 620 g V = 753 cm 3 D = ? D M V WORK : D = M V D = 620 g 753 cm 3 D = 0.82 g/cm 3

Measurement II. Graphing  Types of graphs  Graphing & Density

A. Types of Graphs  Line Graph  shows the relationship between 2 variables Dependent Variable Independent Variable

A. Types of Graphs  Bar Graph  shows information collected by counting

A. Types of Graphs  Pie Graph  shows distribution of parts within a whole quantity

B. Graphing & Density Mass (g) Volume (cm 3 )

Measurement III. Unit Conversions  SI Prefix Conversions  Dimensional Analysis

A. SI Prefix Conversions 1. Find the difference between the exponents of the two prefixes. 2. Move the decimal that many places. To the left or right?

= A. SI Prefix Conversions NUMBER UNIT NUMBER UNIT 532 m = _______ km 0.532

A. SI Prefix Conversions mega-M10 6 deci-d10 -1 centi-c10 -2 milli-m10 -3 PrefixSymbolFactor micro-  nano-n10 -9 pico-p kilo-k10 3 move left move right

A. SI Prefix Conversions 1) 20 cm = ______________ m 2) A = ______________ mA 3) 45  m = ______________ nm 4) 805 dm = ______________ km ,000 32

B. Dimensional Analysis  The “Factor-Label” Method  Units, or “labels” are canceled, or “factored” out

B. Dimensional Analysis  Steps: 1. Identify starting & ending units. 2. Line up conversion factors so units cancel. 3. Multiply all top numbers & divide by each bottom number. 4. Check units & answer.

B. Dimensional Analysis  Lining up conversion factors: 1 in = 2.54 cm 2.54 cm 1 in = 2.54 cm 1 in 1 in = 1 1 =

B. Dimensional Analysis  Your European hairdresser wants to cut your hair 8 cm shorter. How many inches will he be cutting off? 8 cm1 in 2.54 cm = 3.15 in  cmin

B. Dimensional Analysis  How many milliliters are in 1 quart of milk? 1 qt 1 L qt = 946 mL qtmL 1000 mL 1 L

B. Dimensional Analysis 5) Assume your mass is 55 kg. How many pounds do you weigh? 55 kg2.2 lb 1 kg = 121 lb kglb

B. Dimensional Analysis 6) How many feet long is a 5K (5 km) race? 5 km 1 mi km = 16,408 ft kmft 5280 ft 1 mi

B. Dimensional Analysis 7) How many grams does a 10-lb. bag of potatoes weigh? 10 lb 1 kg 2.2. lb = 4545 g lbg 1000 g 1 kg

B. Dimensional Analysis 8) Taft football needs 550 cm for a 1st down. How many yards is this? 550 cm 1 in 2.54 cm = 6.01 yd cmyd 1 ft 12 in 1 yd 3 ft