Overview
This lecture covers essential scientific reasoning concepts for the ATI TEAS 7 Science section, including the metric system, measurement tools, empirical evidence, variables, cause and effect, scale, and the scientific method.
Metric System & Measurement
- The metric system is a decimal-based standardized measurement system using meters (length), grams (mass), and liters (volume).
- The mnemonic "King Henry Doesn't Usually Drink Cold Milk" helps recall metric prefixes from kilo- to milli-.
- Prefixes for larger units: kilo- (×1000), hecto- (×100), deca- (×10); for smaller units: deci- (÷10), centi- (÷100), milli- (÷1000).
- Convert metric units by moving the decimal point left or right based on the prefix direction.
Choosing Measurement Tools & Units
- Rulers measure short lengths (e.g., pencil), tape measures measure longer distances (e.g., door), calipers measure small dimensions (e.g., ball bearing).
- Balance scales, digital scales, and spring scales measure mass; use appropriate scale per context.
- Graduated cylinders (liquids), measuring cups (liquids/solids), and pipets (small liquid amounts) measure volume.
- Use millimeters (very small), centimeters (everyday items), meters (room size), kilometers (geographical); milligrams, grams, kilograms for mass; milliliters, liters, kiloliters for volume.
Empirical Evidence & Data Types
- Empirical evidence is information obtained via observation or experimentation, supporting or refuting hypotheses.
- Qualitative data describes qualities or characteristics (e.g., color, texture).
- Quantitative data uses numbers to describe measurements (e.g., length, frequency).
Variables in Experiments
- Independent variable: manipulated by researcher to observe effects.
- Dependent variable: measured outcome affected by independent variable.
- Controlled variable: kept constant to ensure accurate results.
- Example: In plant growth experiments, sunlight amount is independent; plant growth is dependent; soil type and water schedule are controlled.
Cause and Effect Relationships
- The independent variable is the cause; the dependent variable is the effect.
- Keywords like "since," "because," signal causes; "therefore," "consequently," signal effects.
- Relationships can involve single/multiple causes or effects, or chains of events.
Scale & Appropriate Measurement
- Use meters/millimeters for patient height or tissue thickness; kilograms/grams for patient or organ weight.
- Temporal scales include years, months, days for longer processes; minutes, seconds for short events.
Scientific Method Steps
- Observation: noticing a problem or phenomenon.
- Research: background information from reliable sources.
- Hypothesis: an "if-then" statement predicting results.
- Experiment: test hypothesis using experimental and control groups; collect qualitative and quantitative data.
- Conclusion: interpret data to accept or revise hypothesis.
- Share Results: communicate findings via journals or presentations.
- Repetition: repeat experiments to verify reliability and accuracy.
Key Terms & Definitions
- Metric System — Decimal-based measurement system using standard units for length, mass, and volume.
- Empirical Evidence — Information obtained through observation or experimentation.
- Independent Variable — Variable manipulated to assess its effect.
- Dependent Variable — Variable measured in response to the independent variable.
- Controlled Variable — Conditions kept constant to ensure experimental reliability.
Action Items / Next Steps
- Review and practice metric system unit conversions.
- Memorize scientific method steps and types of variables.
- Complete any assigned readings or practice questions on scientific reasoning.