Defining Physical Science

Defining Physical Science

Defining Physical Science: Physical Science: The study of matter and energy A merging of two major braches of Science: 1. Chemistry: Study of the composition and changes of matter 2. Physics: Study of energy and laws of motion (i.e. the behavior of matter)

Advances in Physical Science: Advances first stem from a need, followed by inquiry. Science is the investigation of rational concepts capable of being tested by observation and experimentation. This analytical method distinguishes science from all other disciplines.

Advances in Physical Science: Scientists: Question natural phenomenon Observe the world around them. Read a variety of scientific books. Become science teachers. You are a scientist if you do any of these!

Advances in Physical Science: Basic Assumptions of Science: There is order in the universe. The human mind is capable of understanding it. Natural phenomenon is testable by experimentation that is repeatable. A real Scientist will attempt to answer their questions.

Scientific Method: The Scientific Method: A systematic approach to problem solving. 1. State the problem: Must first define the problem based on observation of a need. 2. Gather information on the problem: -- Leave no stones unturned The problem may already be solved at least partially.

Scientific Method: 3. Form A Hypothesis: A plausible prediction of the outcome of experimenting. - Use deductive reasoning (if/then statement) - e.g. If I use a fuel additive in my car, then it should improve its mileage. - Hypothesis are often stated as a question.

Scientific Method: 4. Experiment: Test the Hypothesis -Variable: One factor being tested. -Data: Information outcome of the experiment. Types of Data: 1. Quantitative: Numerical Data 2. Qualitative: Descriptive Data (color, behavior, etc)

Scientific Method: Must use a control set-up and experimental set-up. -The experimental set-up contains the variable to be tested, the control does not. -The control is the standard for comparison.

Scientific Method: 5. Record and Analyze data: -Use Accurate Measurements 6. State Conclusions: -Only after the experiment has been repeated to insure accuracy.

Scientific Method: Theory: The most logical explanation of events occuring in nature. Developed through repeated tests. Law: A repeatedly tested theory.. Generally accepted as true, but may be modified after further discoveries. Fact: The absolute truth.

Scientific Method In Practice: 1. The problem: A need to lower the freezing point of H 2 O to -10 C. 2. Information on the Problem: -H 2 O freezes at 0 C -Ethylene glycol freezes at -30 C 3. Hypothesis: One part ethylene glycol to 10 parts H 2 O will lower the freezing point to -10 C.

Scientific Method In Practice: 4. Experiment: Set up 6 replications of 1:10 ethylene glycol and H 2 O mixtures. Decrease Temperature.

Scientific Method In Practice: Data or Data Set 5. Record and Analyze Data Control: Experiment: H 2 O C H 2 O w/ 1/10 Ethylene Glycol 0-4 0-3 0-2 0-3 0-4 0-2 X= 0-3 C

Scientific Method In Practice: 6. Conclusion: The freezing point of H 2 O with 1/10 ethylene glycol is -3 C. Caution: Never test more than one variable at a time. Use graphs to ease in interpreting data.

Temperature (C) Time of Freezing of H 2 O with 1/10 Ethylene glycol (antifreeze) Time (min) Temp C 0 25 10 22 20 19 30 12 40 5 50 0 25 20 15 10 5 0 60-3 -5 0 10 20 30 40 50 60 Time (min) Temp *Spaces between intervals on a graph must be equal. Q: Does this graph represent the control or experimental set-up?

Scientific Terms: Q: What does converge mean? A: Come Together Q: How would the temperature of a reacting substance be affected in an endothermic reaction? A: Temperature would go opposite of exothermic.

Scientific Measurements: Measurements must be accurate, reliable, and appropriate to the subject measured. Scientists use the metric or SI System (Système International d Unités).

Scientific Measurements: SI Base Units Derived Units Volume: Liter Weight: Newton Density: Gram/Liter Temperature: Celsius

Scientific Measurements: Length: Measure of distance 1 meter = 39.4 inches ( about 1 yard) = 100 centimeters = 1000 millimeteres 1000 meters = 1 kilometer Common tools for measuring length Meter Stick Metric Ruler Metric Tape Rolotape

Scientific Measurements: Metric prefixes, symbols, and multipliers Prefix Symbol Multiplier Exponential yotta Y 1,000,000,000,000,000,000,000,000 10 24 zetta Z 1,000,000,000,000,000,000,000 10 21 exa E 1,000,000,000,000,000,000 10 18 peta P 1,000,000,000,000,000 10 15 tera T 1,000,000,000,000 10 12 giga G 1,000,000,000 10 9 mega M 1,000,000 10 6 kilo k 1,000 10 3 hecto h 100 10 2 deca da 10 10 1 1 10 0 deci d 0.1 10 1 centi c 0.01 10 2 milli m 0.001 10 3 micro µ 0.000001 10 6 nano n 0.000000001 10 9 pico p 0.000000000001 10 12 femto f 0.000000000000001 10 15 atto a 0.000000000000000001 10 18 zepto z 0.000000000000000000001 10 21 yocto y 0.000000000000000000000001 10 24

Scientific Measurments: Volume: Amount of space an object takes up Basic Unit: Liter (L) or Cubic Centimeter (cc or cm 3 ) Liters are usually used to measure liquid volume. cm 3 is usually used to measure solids. e.g. The volume of a box can be measured by length x width x heigth 1 cm 3 = 1 milliliter (1/1000 liter)

Scientific Measurments: How could you measure the volume of an irregular shaped object in liters? Liquid volume is measured using a graduated cylinder. Measurements are read at the bottom of the meniscus (curved surface) Bottom of Meniscus

Scientific Measurement: Mass: The amount of matter in an object. Basic Unit: Kilogram (1000 grams) Mass is usually measured using a triple beam balance. Note: Mass is not the same as weight.

Scientific Measurements: Density: The amount of mass in a given volume of an object. Density may be affected by: 1. Air trapped in the object. 2. Temperature of an object.

Scientific Measurements: Density = Mass per unit volume of a substance Calculated by: Density = mass divided by volume d= m V Water density 1 g/ml

Scientific Measurements: Q: If wood floats in water, is its density greater than or less than one?

Scientific Measurements: Temperature: The amount of heat in an object Basic Unit: Kelvin (K) Derived Unit: Celsius ( C) 0 C = Freezing point of water 100 C = Boiling Point of water Body Temp: 37 C Room Temp: 21 C Measured using a thermometer (usually alcohol)

Scientific Measurements: To convert temperatures: K = C + 273 C = K -273 F = 9/5( C + 32) C = 5/9( F 32)

Dimensional Analysis: Dimensional Analysis (DA): Method of converting one unit to another Uses a conversion factor- a factor that is always equal to one e.g. 1000 grams 1 or 1kilogram 1 1 kilogram 1000grams

Dimensional Analysis: Convert 1350 grams to kilograms 1350 grams x 1 kilogram 1 1000grams Cancel grams and multiply. 1350 x 1 kilogram = 1350 kg =1.35kg 1 1000 1000

Lab Safety: Never do anything until you are instructed. Wear safety glasses in the lab when you: Use fire of any kind. Handle hot glass. Measure, mix or pour hot chemicals.