Lecture 1 Methods of Science Ozgur Unal NIS – PHYSICAL SCIENCE Lecture 1 Methods of Science Ozgur Unal

NIS – PHYSICAL SCIENCE Lesson objectives: Define science Identify the steps scientists often use to solve problems Determine dependent variables, independent variables and constants in an experiment.

Scientific Method Science is a process that uses observation and investigation to gain knowledge about the events in nature. Observation: Use our senses Investigation: Includes observing, experimenting, modelling Investigations follow a general pattern: Scientific Method

Scientific Method Scientific Questions Hypothesis: Educated guess, testable answers Experiment: A way to test your hypothesis Collect data Analyze data Draw conclusions Experiments include variables: Dependent variables Independent variables Constants

Scientific Method Question: How does the thickness of the seed coat affect the germination rate of the seeds? Hypothesis? If the thickness of the coating is smaller, the seeds germinate faster. Design an experiment to test your hypothesis: A seed with scratched coat A seed with a hole in the coat (nicked) A seed with an unscratched coat

Scientific Method Identify variables: Coating thickness Independent variable: Dependent variable: Constant: Coating thickness Germination rate Temperature, amount of sunlight, water etc. Control: The seed with normal coating is used to compare the growth rates.

Perform the experiment, collect and record your data: Scientific Method Perform the experiment, collect and record your data: Type of seed Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Control 1 8 15 Sanded 3 9 12 24 Nicked 4 7 19 29 Draw conclusions: ?? Share your results: Communicate

Scientific Method A theory is an explanation of a set of related observations or events based upon hypotheses and verified multiple times by detached groups of researchers. A theory is broader, more detailed and can give testable predictions. A law is a concise but general statement about how nature behaves. (e.g F=m*a) For less general statements, we use the term principle. (e.g. Archimedes’ Principle)

Scientific Method Does microwave popcorn pop better when it has been frozen? Construct a hypothesis Design an experiment to determine whether microwave popcorn pops better when it has been frozen. For tomorrow!

Lecture 2 Standards of Measurements Ozgur Unal NIS – PHYSICAL SCIENCE Lecture 2 Standards of Measurements Ozgur Unal

Standards of Measurements A standard is an exact quantity that people agree to use to compare measurements. The measurement of any quantity is made relative to a particular standard or unit. The length of an object is 2.3  meaningless If people do not use common units, confusions are inevitable.

SI SI, International System of Units, is widely used in the world. SI, is based on multiples of ten. English system is also used by many. Important to specify units to avoid even catastrophes! See the handout.

SI A base unit must be defined in terms of a standard. SI has 7 base units. All other units are derived from base units. For example: unit of speed (m/s), unit of energy (Joule)

Converting Between SI Units A conversion factor is a ratio that is equal to one and is used to change one unit to another. For example, there are 1,000 mL in 1 L. 1,000 mL = 1 L or 1,000mL / 1L = 1 To convert one litre to millilitre, use this conversion factor.

Accuracy vs Precision Accuracy: Compares how close your measurements are to the real or accepted value Precision: Describes how closely measurements are to each other and how carefully measurements were made.