Natural Sciences and Experimental Design Quiz

Absolute Error and Rounding

• Absolute error formula: Error absolute = Scale/2
• Rounding rule for numbers ending in 5: adjust to make the preceding number even.
• Example: 2.25 rounds to 2.2; 2.35 rounds to 2.4.

Experimental Design

• Involves reading a passage and identifying variables, constants, title, and hypothesis.
• Title structure: "The effect of (Independent variable) on (Dependent variable)."
• Hypothesis format: "If (condition), then (outcome), because (reason)."
• Independent variable: manipulated variable.
• Dependent variable: variable affected by manipulation.
• Control variable: original state prior to independent variable manipulation.
• Constants: conditions that remain unchanged throughout the experiment.

Natural Sciences

• Two main fields: Biological Sciences and Physical Sciences.
• Biological Sciences: studies living organisms (e.g., Botany, Zoology, Microbiology).
• Physical Sciences: focuses on non-living matter and laws of nature (e.g., Physics, Chemistry, Astronomy).

Chemistry

• Chemistry: science rooted in experimentation leading to observations, theories, and mathematical evaluations.
• Branches of Chemistry:
  • Organic Chemistry: study of carbon-containing compounds.
  • Biochemistry: reactions in living organisms.
  • Inorganic Chemistry: study of non-carbon compounds (e.g., minerals).
  • Analytical Chemistry: statistical analysis and methodologies for observations.
  • Physical Chemistry: relation between energy and matter composition.
• Key concepts:
  • Mass: measure of matter in an object.
  • Volume: space occupied by an object (solid, liquid, gas).

Mathematics

• Scientific notation: consists of a coefficient, base (10), and exponent (positive/negative).
• Negative exponent indicates a small number; positive exponent indicates a larger number.
• Significant figures rules:
  • Leading zeros do not count.
  • Zeros between numbers count.
  • Trailing zeros after a decimal point count; before a decimal, they don’t unless after a number.
  • Example: 700 has 1 significant figure; 700.0 has 4 significant figures.

Arithmetic with Significant Figures

• Addition/Subtraction: result has the smallest number of decimal places among the input values.
  • Example: 22.92 + 7.08 = 30.00 (2 decimal places).
• Multiplication/Division: round to the lowest significant figures from initial values.
  • Example: 3.00 x 12 x 78.201 = 2800 (rounded to 2 significant figures).

Metric System

• Length: meter (m), time: second (s), volume: liter (L), mass: gram (g).
• Metric prefixes:
  • Tera (T) = 1 x 10^12
  • Giga (G) = 1 x 10^9
  • Mega (M) = 1 x 10^6
  • Kilo (k) = 1 x 10^3
  • Deca (da) = 1 x 10^1
  • (Base unit)
  • Deci (d) = 1 x 10^-1
  • Centi (c) = 1 x 10^-2
  • Milli (m) = 1 x 10^-3
  • Micro (µ) = 1 x 10^-6
  • Nano (n) = 1 x 10^-9
  • Pico (p) = 1 x 10^-12
  • Femto (f) = 1 x 10^-15

Volume and Density

• Water displacement method: used for irregular objects; measure water level before and after submerging the object and subtract.
  • State volume in cm³ or m³ (1000 L = 1 m³; 1 mL = 1 cm³).
• Regularly shaped objects: volume calculated by multiplying length, width, and height.
• Density formula: d = m/v (density = mass/volume).
• Dimensional analysis: converting between different units.