Bell Work 08132012 Write question and answer in

Bell Work 08/13/2012 Write question and answer in notes • What are the steps to the scientific method?

Unit 1 Essential Question What tools, skills, and knowledge are needed to conduct scientific inquiry?

What is the purpose of the scientific method? • Logical approach to solving problems by observing and collecting data, formulating hypothesis, testing the hypothesis, and to formulate theories that are supported by data

Observation vs. Inference Observation Inference • What you see • May also be based on senses • Conclusion or assumption made by using context clues/observations

Hypothesis • If, then statement • Example: (I have a headache) – If I take an aspirin; then, I will no longer have a headache.

Deductive vs. Inductive reasoning Deductive Reasoning Inductive Reasoning • General Specific • Example: All bachelors are single men. Johnny is a single man. Therefore, Johnny is a bachelor. • Specific General

Qualitative vs. Quantitative Qualitative Data – Description of observation – Sky is blue (color) Quantitative Data – Numerical value – Copper ore has a mass of 25. 7 – Readings of mass, temperature, volume

Experiments • Variable – A quantity that can have more than a single value • Independent variable • Dependent variable • Constant – Factor that does not change when other variables change • Control – Standard by which test results can be compared to

Independent vs. Dependent Variables Independent Variable Dependent Variable is manipulated This is the cause Plotted on x-axis • Response • The effect • Plotted on the y-axis

Exit Slip 08/13/2012 • Differentiate between qualitative data and quantitative data.

Bell Work 08 -14 -2012 • Please write question and answer. Differentiate between scientific law and scientific theory. A theory can change if its supporting data changes. A law is assumed to be true and doesn’t change. Also, a law tells what happens but does not explain why. Theories try to explain why things happen.

SI Unit • Standards of measurement – Standard: exact quantity that people agree to use for comparison • Constant values • Easy to preserve and reproduce • Practical in size

Direct Measurements • Base Units – Mass; kilogram; kg – Length; meter; m – Time; seconds; s – Temperature; Kelvin; K – Electric current; ampere; A – Amount of substance; mol

SI unit Prefixes • • • kilo- 1000 hecto-100 deka-10 BASE UNIT-1 deci-. 1 (10) centi-0. 01 (100) milli-0. 001 (1000) micro-0. 000001 (1000000) nano-0. 00001 (100000)

Conversion Factors • Used to change one unit to another • We use dimensional analysis to convert between units

Teacher Example • 42 g = kg

Class Practice • 3. 61 ml = L

You Practice • 8 m= cm

Derived SI Units • What are derived units? – Combinations of SI Base units by multiplying or dividing standard units • Table 3 page 36

Formulas You Should Know • Volume (V) = length x width x height – Cubic meter or m³ – 1 cm³/1 m. L • Density (D) = mass/volume – Kilograms per cubic meter or kg/m³ • Molar mass (M) = mass/amount of substance – Kilograms per mole or kg/mol

What is density? • Ratio of mass to volume “how much stuff you have in a given space” • kg/m ³ is too large of a value to work with in the lab; so, often expressed as g/cm³, g/ml, and for gasses g/L or kg/L.

Rules to follow for working math problems 1. Write down all the information that is given in the problem and put a box around it. This is your “given box” 2. Write the equation that you are going to use to solve the problem. 3. Manipulate the equation if necessary to get the desired variable on the left side of the equal sign 4. Plug in your given and solve 5. Box in your answers 6. Units must be clearly marked throughout the entire problem, especially in the answer.

Practice Problem • A sample of aluminum metal has a mass of 8. 4 g. The volume of the sample is 3. 1 cm ³. Calculate the density of aluminum. Given: mass (m) = 8. 4 g volume (V)= 3. 1 cm ³ Unknown: Density

Practice Problem • What is the density of a block of marble that occupies 310 cm ³ and has a mass of 853 g? • 2. 75 g/cm

Practice Problem • Diamond has a density of 3. 26 g/cm³. What is the mass of a diamond that has a volume of 0. 351 cm ³? • 1. 14 g

Practice Problem • What is the volume of a sample of liquid mercury that has a mass of 76. 2 g given that the density of mercury is 13. 6 g/m. L? • 5. 60 m. L

Science, Technology, Society • Baby born today is expected to live 30 yrs longer than a baby born 100 yrs ago. Chemistry has made this possible by: • Manufacturing of vaccines and antibiotics • Increased understanding of human nutritional needs • Fertilizers in argriculture

Nutrition • Keeps food fresher longer • Refrigeration, pasteurization, drying, salting, add preservatives • Chemical techniques give fatty acids, amino acids, vitamins, and minerals

Everyday Applications • Does adding salt to water while boiling make the water boil faster? • Antacids • Yeast • A lot of chemical technology that saves lives or improve quality of life has had a negative impact on environment. • Ex: fossil fuels, acid rain, ozone layer