Unit 3 | Basic Scientific Principles

🔹 Chapter 1: Scientific Investigation

Section 1: Hypothesis Testing

1. Define hypothesis testing
   A process to test an assumption (hypothesis) about a population using data.

2. Understand the types of hypotheses

   • Null (H₀): No effect/difference.

   • Alternative (H₁): Shows effect/difference.

3. Outline the steps in hypothesis testing

   1. State H₀ and H₁

   2. Choose significance level (α)

   3. Select test statistic

   4. Determine critical region

   5. Collect data and compute statistic

   6. Compare and conclude (reject or fail to reject H₀)

4. Formulate a null hypothesis
   A default assumption (e.g., "The medicine has no effect").

5. Formulate an alternative hypothesis
   A statement that contradicts H₀ (e.g., "The medicine improves health").

6. Select a significance level

   • Common α levels: 0.05, 0.01

   • Represents the probability of Type I error (false positive)

7. Choose an appropriate test statistic

   • Depends on data type (e.g., t-test for means, chi-square for categories)

Section 2: Experimental Design

1. Define the problem
   State clearly what is being tested or investigated.

2. Formulate a hypothesis
   Create testable H₀ and H₁ based on the problem.

3. Design an experiment
   Plan method: variables, controls, and procedure.

4. Conduct the experiment
   Follow the procedure; control bias and maintain consistency.

5. Analyze the data
   Use statistical tools to interpret results.

6. Draw conclusions
   Decide whether to reject or fail to reject H₀ based on data.

Section 3: Data Analysis

1. Define data analysis and its importance
   Organizing and interpreting data to extract meaning and support conclusions.

2. Identify data sources and types

   • Sources: surveys, sensors, experiments

   • Types: quantitative (numbers), qualitative (descriptions)

3. Learn data collection methods

   • Surveys, observations, experiments

   • Important: reliability and validity

4. Apply data preprocessing techniques

   • Cleaning, normalization, handling missing data

5. Perform exploratory data analysis (EDA)

   • Use graphs, summaries to understand patterns/trends

6. Implement statistical analysis

   • Inferential methods: t-tests, correlation, regression

7. Use visualization tools for data interpretation

   • Graphs, charts (histograms, scatterplots, boxplots)

8. Develop data-driven decision-making strategies

   • Use insights to support logical and strategic decisions

9. Address data quality issues

   • Check for bias, outliers, duplicates, and missing entries

10. Understand data security and privacy

• Protect sensitive information; follow legal/ethical guidelines

🔹 Chapter 2: Measurement Systems

Section 1: SI Units

1. Define SI units
   Standardized system (International System of Units)

2. Identify the base SI units

   • Meter (m), Kilogram (kg), Second (s), Ampere (A), Kelvin (K), Mole (mol), Candela (cd)

3. Learn the derived SI units

   • Formed from base units:
     Example: Newton (N) = kg·m/s², Joule (J) = N·m

4. Understand the prefixes used with SI units

   • kilo- (10³), centi- (10⁻²), milli- (10⁻³), etc.

5. Convert between different SI units
   Use conversion factors or move the decimal based on prefix scale.

6. Practice using SI units in calculations
   Ensure consistency in units when solving equations.

Section 2: Measurement Conversions

1. Define measurement units
   Quantities used to express physical dimensions (e.g., length, mass)

2. Identify common systems of measurement

   • Metric (SI), US customary

3. Understand conversion factors
   Ratios used to convert between units (e.g., 1 inch = 2.54 cm)

4. Convert between units within the same system
   Example: 1 km = 1,000 m

5. Convert between units in different systems
   Use conversion ratios (e.g., inches to cm)

6. Apply conversion factors in practical examples
   Solve problems using unit conversion in real-world contexts

7. Use conversion tools and tables effectively
   Use charts, calculators, or software for accuracy

Section 3: Practical Measurement

1. Define what measurement is and its importance
   Quantifying physical properties for scientific analysis

2. Identify different units of measurement
   Length (m), Mass (kg), Time (s), Volume (L), etc.

3. Learn about measurement tools and devices

   • Ruler, thermometer, balance, stopwatch, etc.

4. Understand error and uncertainty in measurement

   • Error: Deviation from true value

   • Uncertainty: Estimated range of values

5. Apply measurement techniques in practical scenarios

   • Use proper tools, units, and record significant figures accurately

🔹 Chapter 3: Physics Principles

Section 1: Motion and Forces

1. Define motion
   Change in position over time

2. Introduce velocity and acceleration

   • Velocity = speed with direction

   • Acceleration = rate of change of velocity

3. Explore types of forces

   • Contact (friction, tension)

   • Non-contact (gravity, magnetism)

4. Discuss Newton's laws of motion

   1. Inertia

   2. F = ma

   3. Action = Reaction

5. Explain gravitational force

   • Attraction between masses (F = G·m₁m₂/r²)

6. Learn about friction

   • Opposes motion; types: static, kinetic

7. Analyze projectile motion

   • Curved path under gravity; vertical and horizontal components

8. Understand work and energy

   • Work = force × distance

   • Energy: capacity to do work

9. Solve motion problems
   Use equations:

   • d = vt

   • v = u + at

   • F = ma

   • W = Fd

Section 2: Energy and Work

1. Define Energy
   The ability to do work

2. Types of Energy

   • Kinetic, potential, thermal, chemical, nuclear, etc.

3. Define Work
   Work = force × displacement × cos(θ)

4. Relationship between Energy and Work
   Work transfers energy; more work → more energy transfer

5. Work-Energy Theorem
   Net work done = change in kinetic energy (W = ΔKE)

6. Examples of Work Done

   • Lifting objects, moving furniture, pushing a box

7. Units of Energy and Work

   • Joule (J) = N·m = kg·m²/s²

Section 3: Simple Machines

1. Define simple machines
   Tools that change force direction/magnitude to make work easier

2. Identify common simple machines

   • Lever, pulley, wheel and axle, inclined plane, screw, wedge

3. Explain mechanical advantage of simple machines
   MA = Output Force / Input Force

   • Higher MA = easier work

4. Describe applications of simple machines in everyday life

   • Scissors (wedge), ramps (inclined plane), doorknobs (wheel and axle)

5. Differentiate between simple and complex machines

   • Simple: 1 mechanism

   • Complex: combo of simple machines (e.g., bicycle)

6. Solve problems involving simple machines
   Use formulas for MA, efficiency, and force-distance trade-offs