Chapter 1 Science Skills Test Review

Nature of Science and Branches of Study

• Definition of Science:

  • Science is defined as the system of knowledge and the methods used to find that knowledge.

• Branches of Natural Science:

  • Natural science is divided into three main branches:
  • Life Science: The study of living systems and organisms.
  • Earth and Space Science: The study of Earth and space systems.
  • Physical Science: The study of non-living systems, matter, and energy.

• Social Science:

  • Social science is not a branch of natural science.

• Main Areas of Physical Science:

  • Physical science is divided into two primary areas:
  • Physics: The study of matter, energy, motion, and forces.
  • Chemistry: The study of the composition, structure, properties, and reactions of matter.

• Overlaps Between Scientific Fields:

  • Earth science overlaps with biology because Earth science involves the study of Earth systems that may include living organisms.

• Main Ideas of Physical Science:

  • Space and Time: The universe is very old and very large.
  • Matter and Motion: Forces cause changes in motion.
  • Energy: Energy can be transferred from one form to another, but it can never be destroyed.
  • Atoms: Atoms are the fundamental building blocks of all matter.

Scientific Method and Investigation Procedures

• Definition of Scientific Method:

  • An organized plan used for gathering, organizing, and communicating information.

• Observation:

  • The step in the scientific method where information is directly obtained through the human senses.

• Hypothesis Testing and Revision:

  • When data obtained in an investigation does not support the original hypothesis, the hypothesis will be revised.

• Controlled Experiments:

  • An experiment in which only one variable, the manipulated variable, is changed at a time.
  • Manipulated Variable (Independent Variable): The variable that is intentionally changed by the experimenter.
  • Responding Variable (Dependent Variable): The variable that changes in response to the manipulated variable.

• Scientific Laws:

  • A scientific law is a concise statement that summarizes a pattern consistently found in nature.

• Scientific Theories:

  • Scientific theories offer explanations for natural phenomena and are never proven.

• Scientific Models:

  • Physical or mental representations of an object or an event.
  • Models are important because they help visualize things that are very complex, very large, or very small.

• Laboratory Safety Procedures:

  • The most important safety rule is to always follow your teacher's instructions and textbook directions exactly.
  • Safe laboratory procedures include tying back long hair and loose clothing before beginning an experiment.

Scientific Communication and Peer Review

• Methods of Communicating Results:

  • Scientists communicate the results of investigations by writing in scientific journals or speaking at scientific conferences.

• Importance of Peer Reviews:

  • Peer reviews allow scientists to receive questions and criticism from their peers.
  • Experimental data are checked for accuracy.
  • Scientists receive comments and suggestions from other scientists to improve or validate their work.

• International System of Units (SI):

  • Scientists who speak different languages use standardized SI units to make their data universally understandable to one another.

Measurement, Units, and Conversions

• Essential Components of a Measurement:

  • A valid scientific measurement must include both a number and a unit.

• SI Base Unit of Mass:

  • The SI base unit used to measure mass is the kilogram ($\text{kg}$).

• Metric Conversions and Conversion Factors:

  • Kilometers to Meters: Converting a measurement from kilometers to meters involves multiplying the number by $1000$.
  • Conversion factor for $15\,\text{km}$ to meters:       $15\,\text{km} \times \frac{1000\,\text{m}}{1\,\text{km}} = 15\,000\,\text{m}$
  • Centimeters to Millimeters:     $1\,\text{cm} = 10\,\text{mm}$
  • Seconds to Milliseconds:     $0.017\,\text{s} = 17\,\text{ms}$
  • Megawatts to Kilowatts:
  • Annually, $1350\,\text{MW}$ of wind-generated electricity is produced globally. This value is equivalent to:       $1350\,\text{MW} \times \frac{1000\,\text{kW}}{1\,\text{MW}} = 1\,350\,000\,\text{kW} = 1.35 \times 10^6\,\text{kW}$

• Scientific Notation:

  • Scientific notation expresses numbers as a factor multiplied by a power of $10$.
  • The number $0.00034$ written in scientific notation is:     $3.4 \times 10^{-4}$

• Temperature Scales and Conversions:

  • Converting Fahrenheit to Kelvin:     To convert $50\,^{\circ}\text{F}$ to Kelvin:     $C = \frac{5}{9}(50 - 32) = 10\,^{\circ}\text{C}$$K = 10 + 273 = 283\,\text{K}$
  • Reference Temperatures:
  • Water boiling point (Celsius scale): $100\,^{\circ}\text{C}$
  • Water freezing point (Fahrenheit scale): $32\,^{\circ}\text{F}$
  • Water freezing point (Celsius scale): $0\,^{\circ}\text{C}$
  • Water freezing point (Kelvin scale): $273\,\text{K}$

Data Precision, Accuracy, and Mathematical Relationships

• Accuracy vs. Precision:

  • Accuracy: The closeness of a measurement to the actual or true value being measured.
  • Precision / Quantity of Data: A clock that measures time to the nearest tenth of a second ($0.1\,\text{s}$) offers more precise data than a clock that only measures to the nearest second ($1\,\text{s}$).

• Significant Figures:

  • The measurements $10.714\,\text{m}$, $12.821\,\text{m}$, and $13.646\,\text{m}$ all contain the exact same number of significant figures ($5$ significant figures).
  • In calculations, the answer is limited by the factor with the fewest significant figures.
  • For the calculation $65.2 \times 37$, because $37$ has $2$ significant figures, the final answer will have $2$ significant figures ($65.2 \times 37 = 2412.4 \rightarrow 2400$ or $2.4 \times 10^3$).

• Mathematical Variable Relationships:

  • Direct Proportion:
  • A relationship between variables where doubling the manipulated (independent) variable results in a doubling of the responding (dependent) variable.
  • A line graph depicting a direct proportion shows a straight, upward-sloping line.
  • Inverse Proportion:
  • The relationship between two variables where the product of the variables remains constant ($x \times y = k$).

Data Representation and Graphical Analysis

• Line Graph:

  • A plot of data used to show continuous changes that occur in related variables.

• Circle Graph (Pie Chart):

  • Used to show how a part or fraction of something relates to the whole ($100\%$).

• Bar Graph:

  • Used to compare distinct categories or measurements.
  • A bar graph is the best chart type to use when comparing levels of lead contamination across six individual water wells.

Scientific Technology

• Definition of Technology:

  • Technology represents practical applications that help people solve problems.
  • Example: Computers are an example of technology that aids problem-solving.

• Interdependence of Science and Technology:

  • Science and technology are closely related because advances in science may lead to advances in technology, and advances in technology may lead to advances in science.