Scientific Methods and Matter Summary & Study Notes

🔬 Scientific Method & Observations

• Learning goals: I can explain the steps in scientific investigations and I can make appropriate observations.

• Scientific Method: The Scientific Method is an ordered way to learn about something. It can be used to study anything from a leaf to a dog to the Universe. It involves four areas of skills: Initiating and planning, Performing and recording, Analyzing and interpreting, and Communicating.

• Advantages: A main advantage of using the scientific method is to minimize bias in answering a question. We focus on a few selected tasks in each area of skills.

• Types of variables: There are three types of variables in an experiment:

  • Independent variable: the thing that you intend to change
  • Dependent variable: the thing that may change when you change the independent variable
  • Control variable: the things that do not change during the experiment

• Hypothesis: Use what you already know to make a guess or prediction about what will happen. Always write your hypothesis in the form: If ___ (changes in the independent variable) ___, then ___ (predicted changes in the dependent variable) ___. Example: If the plant gets more water, then it will grow taller.

• Observations: Observations are based on facts; they can be repeated, recorded, shared, and described in detail. The example provided is an observation like “The air temperature is $6^{\circ}C$.”

• Recording observations: Describe what happened using words, numbers, pictures; you can describe it, draw it, graph it, map it, photograph it, or videotape/audiotape it.

• Improper observations: Avoid vague or “made up” observations such as “Thingy,” “Looks like water,” or “Smells like marker.”

• Qualitative vs. Quantitative:

  • Qualitative observations describe qualities using senses (sight, hearing, touch, smell). Example: color or texture.
  • Quantitative observations use numbers (measuring or counting). Example: height, weight, temperature.

• Observations vs. inferences:

  • Observations are what you directly observe.
  • Inferences are explanations or conclusions drawn from observations, based on reasoning and prior knowledge.

• Communication (lab reports): After an experiment, scientists share results in a lab report. Typical sections include: PROBLEM / PURPOSE, HYPOTHESIS, MATERIALS, PROCEDURE, OBSERVATIONS, DISCUSSION, and CONCLUSION.

• Tip: Practice completing the Lesson 2 worksheet on scientific method and observation.

🧰 Lab Safety / WHMIS & HHPS

• Learning goals: I know and practice the WHMIS system and pictograms; I can explain safe practices and procedures when planning investigations; I can select appropriate instruments.

• Lab safety equipment (examples): Common items include Fire Extinguishers, Glass Disposal Containers, Safety Goggles, Fire Alarms, First Aid Kits, and Eyewash Stations. Locations vary by room but safety gear is placed near work areas and exits.

• Lab safety activity: Identify hazards such as not wearing goggles, hair left loose, broken glass, flammable liquids near flames, unattended flames, cluttered work areas, food in the lab, climbing on stools, unsafe handling of heated tubes, spills, or wearing a cap during lab work.

• Lab safety rules & procedures (highlights):

  • Do not bring food or drink into the science classroom.
  • If chemical spills contact skin, wash with water and inform your teacher.
  • If chemicals get into eyes, use the eyewash station for at least 15 minutes and inform your teacher.
  • Do not flush hazardous chemicals down the drain; dispose of chemicals as instructed by your teacher.
  • Broken glass should be disposed of in the proper container.

• WHMIS (Workplace Hazardous Materials Information System): Canada’s national standard for communicating information about hazardous workplace products. It applies to most hazardous products in workplaces in Canada (with certain exclusions). The main elements are:

  • i) Product classification
  • ii) Labels
  • iii) Safety Data Sheets (SDS)
  • iv) Worker education

• WHMIS labels:

  • Supplier labels (on the container)
  • Workplace labels (when the product is produced or used at work)

• WHMIS pictograms: Key symbols include Gas Cylinder, Flame, Flame over Circle (oxidizer), Exclamation mark, Health hazard (including long-term hazards), Skull and Crossbones (acute toxicity), and Biohazardous Infectious Materials.

• Hazardous Household Product Symbol (HHPS): Used for household products. The border and inside symbol carry meaning. Common HHPS containers warn of flammability, corrosion, explosion risk, and poisoning. Examples include aerosols, bleach, windshield washer fluid, and furniture polish.

• HHPS categories and examples:

  • Explosive container hazards (could explode if heated or punctured)
  • Corrosive products (burn skin/eyes)
  • Flammable products (catch fire easily)
  • Poisonous products (toxic if ingested or inhaled)

⚗️ Classifying Matter

• What is matter? Matter is anything that has mass and volume.

• Particle Theory basics: Matter is made of tiny particles. Each pure substance has its own kind of particles. Particles have spaces between them, and those spaces are large compared to particle size in gases. Particles attract each other, and they are always moving (faster at higher temperatures).

• Five statements of the Particle Theory:

  1. All matter is made up of tiny particles
  2. Each pure substance has its own kind of particles
  3. All particles have spaces between them; these spaces are large relative to particle size
  4. Particles attract each other
  5. Particles are always moving; they move faster at higher temperatures

• Matter classification:

  • Pure substance: contains only 1 type of particle
    • Elements: cannot be broken down into simpler substances
      • Examples: $H$, Na, $O$, Cl
    • Compounds: two or more elements in a fixed ratio
      • Examples: $NaCl$, $C_6H_{12}O_6$, $H_2O$, $H_2O_2$
  • Mixtures: contain 2 or more different types of particles
    • Solutions (Homogeneous Mixtures): one phase; substances not visible
      • Examples: $NaCl$ in water, $sugar$ in water
    • Mechanical (Heterogeneous) Mixtures: more than one phase; substances visibly different
      • Examples: Rock & Water, Sand & Stones

• Pure substances vs mixtures (quick recall):

  • Pure substance vs mixture: a pure substance has one type of material, while a mixture contains two or more pure substances physically combined.

• Separation methods for mixtures:

  • Filtration: separate based on particle size differences
  • Distillation: separate based on different boiling points
  • Magnet: separate based on magnetic properties

🧊 Particle Theory of Matter

• What is matter? Matter is anything that has mass and volume.

• What is the Particle Theory? It is a model used to describe the structure of matter and how it behaves.

• The 5 statements (reiterated):

  • All matter is made of tiny particles
  • Each pure substance has its own kind of particles
  • Particles have spaces between them; spaces are large relative to size
  • Particles attract each other
  • Particles are always moving; they move faster at higher temperatures

• State descriptions using the theory:

  • For SOLID: spaces between particles are very small; attractive forces are very strong; movement is very slow; energy level is very low
  • For LIQUID: spaces between particles are small; attractive forces are strong; movement is slow; energy level is high
  • For GAS: spaces between particles are large; attractive forces are weak; movement is fast; energy level is very high

• Change of state (how the theory explains phase changes):

  • Increase temperature: SOLID → LIQUID (melting) → GAS (evaporation)
  • Decrease temperature: GAS → LIQUID (condensation) → SOLID (freezing)
  • Key ideas: heating increases particle movement and energy; phase changes occur as spaces between particles and the strength of attractions change

• Pictorial models (conceptual): Use the ideas of spaces between particles, strengths of attractions, movement, and energy level to describe SOLID, LIQUID, and GAS and transitions between them

• Examples to connect ideas:

  • Water is $H_2O$, and hydrogen peroxide is $H_2O_2$; different compositions mean different particle arrangements and properties.

• Practice prompts encourage explaining state changes with the particle theory in terms of spaces, attractions, movement, and energy.

Notes: This study guide uses inline math for chemical formulas and measurements, such as $H_2O$, $H_2O_2$, and $6^{\circ}C$. Key terms are bolded, and each major section begins with a single emoji heading as shown.