Laboratory Safety and Scientific Methods

Study Guide: Laboratory Safety, Measurement, Scientific Methods, and Environmental Concepts

Intro Lab: Laboratory Safety Rules

• Familiarity with Laboratory Rules, Regulations, and Procedures

  • Importance of understanding safety protocols

  • Locations of emergency equipment

• Proper Laboratory Attire

  • Closed-toe shoes

  • Long pants

  • Shirt with sleeves

  • Hair tied back to avoid hazards

• Eating and Drinking Guidelines

  • Never allowed in lab to prevent contamination and accidents.

• Laboratory Emergency Equipment Locations

  • Eyewash station for chemical splashes in eyes

  • Safety shower for chemical spills on body

  • Fire extinguisher for fire emergencies

  • Fire blanket for smothering flames

  • First aid kit for minor injuries

• Proper Disposal of Biohazard Waste

  • Place waste in designated biohazard containers

  • Never dispose of biohazard waste in regular trash

  • Never pour down the sink unless instructed

Lab #1: Scientific Tools and Techniques

• What are SI Units?

  • SI = International System of Units, standard measurement system in science.

  • Conversion between metric and US customary units is essential for accuracy in experiments.

• Measurement

  • SI Unit Length: meter (m)

  • SI Unit Mass: gram (g)

  • SI Unit Volume: liter (L)

  • SI Unit Temperature: Celsius (°C)

• Metric Conversions

  • 100 cm = 1 m

  • 1000 g = 1 kg

  • 1000 mL = 1 L

  • Conversion Formula from Fahrenheit to Celsius: $°C = (°F - 32) \times \frac{5}{9}$

• Calculating Means or Averages

  • Add all values together and divide by the total number of values to find the average.

• Length

  • Definition: Distance between two points.

  • Basic Unit: Meter (m).

  • Types of Linear Measurement: Length, width, distance, and diameter.

  • Instruments Used: Ruler, measuring tape, measuring wheel.

• Mass

  • Definition: Amount of matter in an object.

  • Basic Unit: Gram (g).

  • Instruments Used: Electronic balance and triple beam balance.

• Volume

  • Definition: Amount of space an object or liquid occupies.

  • Basic Unit: Liter (L) for liquid volume.

  • Instruments Used: Graduated cylinder (most accurate), pipettes, beakers.

• Meniscus

  • Definition: The curved surface of a liquid in a container.

  • Reading: Must be from eye level, at the bottom of the meniscus curve.

• Temperature

  • Definition: Measures how hot or cold something is.

  • Basic Unit: Celsius (°C).

  • Instruments Used: Thermometer.

• Diameter at Breast Height (DBH)

  • Definition: Diameter of a tree measured at 4.5 feet above ground.

  • Calculation Formula: $DBH = \frac{Circumference}{\pi}$ (where $\pi \approx 3.142$)

• Accuracy vs. Precision

  • Accuracy: Closeness of a measurement to the true value.

  • Precision: Consistency of repeated measurements.

  • A measurement can be precise without being accurate.

Labs 2A and 2B: Scientific Investigation and Writing

• What is Scientific Investigation?

  • Systematic process for answering a question using observation, experimentation, and evidence.

• Steps of Scientific Investigation:

  1. Observation: Noticing and describing phenomena.

  2. Question: Formulating a question based on observations.

  3. Literature Review: Research existing information.

  4. Hypothesis: Educated, testable explanation.

  5. Prediction: Statement of expected outcomes (e.g., "If independent variable, then dependent variable").

  6. Experiment: Conducting tests to gather data.

  7. Conclusion: Analyzing results to support or reject the hypothesis.

• Limitations of the Scientific Method:

  • Cannot prove absolute truth.

  • Bias may influence results.

  • Ethical restrictions apply.

  • Some questions cannot be experimentally tested.

• Formulate Testable Hypotheses and Predictions

  • Hypothesis: An educated explanation.

  • Prediction: Example: "If onion extract contains allelochemicals, then seed germination will decrease."

• Factors Important in Experimental Design:

  • Clear definition of variables (dependent, independent, controlled).

  • Establishment of a control group.

  • Replication to validate results.

  • Adequate sample size.

  • Controlled conditions throughout the experiment.

• Types of Variables:

  • Independent Variables: What you change.

  • Dependent Variables: What you measure.

  • Controlled Variables: What remains constant.

• Continuous vs. Discrete Variables:

  • Continuous: Can include decimals (e.g., temperature).

  • Discrete: Whole numbers only (e.g., count of plants).

• Experimental Group vs. Control Group:

  • The experimental group receives treatment, whereas the control group does not.

• Replication and Sample Size:

  • Replication: Repeating experiments multiple times to confirm reproducibility.

  • Sample Size: Total number of subjects tested.

• Data Presentation:

  • Creation of simple graphs and tables from provided or calculated data.

  • Difference between graph types:

  • Line Graph: Shows change over time.

  • Bar Graph: Compares categories.

  • Histogram: Shows frequency distribution.

• Conclusion Development:

  • Based on collected data, compare results with hypotheses to determine support or rejection.

Applying the Scientific Method

• Example Study: Sunscreen and UV Radiation

  • Independent Variable: Type of sunscreen used.

  • Dependent Variable: Level of UV exposure.

  • Hypothesis: If UV exposure decreases with sunscreen use, then it protects against UV rays.

Parts of the Scientific Paper

• Title: Topic of study.

• Authors: Researchers involved in the study.

• Keywords: Main topics of research.

• Abstract: Summary of the study.

• Introduction: Background information and purpose of the study.

• Materials & Methods: Procedures followed during the experiment.

• Results: Presentation of data without interpretation.

• Discussion: Interpretation and relevance of the findings.

• Conclusion: Summary of key findings.

• Acknowledgment: Credits to individuals and organizations that supported the research.

• References: Cited sources used in the study.

Lab 3: Allelopathy: A Plant-Plant Interaction

• What is Allelopathy?

  • Biological interaction where one plant releases chemicals that inhibit the growth of another.

• Plant Competition: Plants compete for essential resources including:

  • Water

  • Light

  • Nutrients

• Species Interactions: Various relationships among organisms, such as:

  • Competition

  • Predation

  • Mutualism

• Effect of Plant Compounds on Seed Germination and Seedling Development

  • Plant chemicals may inhibit seed germination rates and stunt growth of seedlings.

• What are Allelochemicals?

  • Chemicals released by plants affecting neighboring plant species.

• Disadvantages of Using Allelochemicals as Bioherbicides:

  • Potential harm to non-target species.

  • Environmental persistence in ecosystems.

  • Difficulty in dosage control.

• What are Essential Oils?

  • Concentrated extracts from plants containing various terpenes.

• Purpose of Testing Essential Oils in Lab:

  • Observe effects on seed germination rates.

• Controlling Invasive Allelopathic Plants:

  • Methods include:

  • Manual removal

  • Mulching

  • Carefully selected herbicides

  • Replanting of native species.

• Secondary Compounds Classes:

  • Alkaloids: Toxic nitrogen-containing compounds (e.g., nicotine).

  • Terpenes: Fragrant compounds found in essential oils (e.g., eucalyptus oil).

  • Phenols: Defensive compound (e.g., tannins).

Lab 4: Building Green

• What is Building Green?

  • Structures designed, constructed, and operated to minimize environmental impact and improve energy efficiency.

  • Such buildings use fewer resources, produce less waste, and create healthier living environments.

• Advantages of Building Green:

  • Reduced energy and water consumption.

  • Lower environmental impact and pollution.

  • Improved indoor air quality for occupants.

• Disadvantages of Building Green:

  • Higher initial construction costs.

  • Availability issues concerning materials.

  • Necessitates specialized knowledge for construction and upkeep.

• What is Sustainability?

  • Practice of meeting present needs without jeopardizing the ability of future generations to meet their own needs.

  • Responsible resource use and minimizing environmental harm.

• How to Obtain LEED Certification:

  • LEED (Leadership in Energy and Environmental Design) certification is obtained by earning points for sustainable practices in building design and operations.

• Features of LEED-Certified Building:

  • Energy-efficient lighting and appliances.

  • Water-saving fixtures.

  • Use of renewable energy sources such as solar panels.

  • Sustainable materials in construction.

  • Enhanced systems for indoor air quality.

• Energy Use Calculations:

  • Energy use formula: $Energy (kWh) = Power (Watts) \times Time (hours) \div 1000$

  • Annual Energy Use: Daily energy use multiplied by 365.

  • Annual Cost: $Energy (kWh) \times Cost \text{ per } kWh$

• Cost Calculations for Lighting:

  1. Determine wattage of the bulb.

  2. Multiply by hours used per day.

  3. Convert Wh to kWh (divide by 1000).

  4. Multiply by electricity rate to find daily cost.

• Example Calculation for a 60W bulb used for 5 hours:

  • $60W \times 5h = 300Wh$

  • $300Wh \div 1000 = 0.3kWh$

  • Daily cost = $0.3kWh \times electricity price$

• Recommendations for Reducing Environmental Impact:

  • Implement LED lighting.

  • Install solar panels.

  • Enhance building insulation.

  • Employ energy-efficient appliances.

  • Utilize water-saving fixtures.

  • Opt for sustainable construction materials.

• Importance of Environmentally Sustainable Practices:

  • Reduce pollution.

  • Conserve natural resources.

  • Lower energy consumption.

  • Help protect ecosystems for future generations.

• Ways to Reduce Personal Environmental Impact:

  • Reduce energy usage.

  • Recycle materials regularly.

  • Employ reusable bags and bottles.

  • Minimize water consumption.

  • Utilize public transport or carpool when possible.

Online Module: Bioplastics

• Are There Environmentally Friendly Alternatives to Plastic?

  • Yes, including:

  • Bioplastics derived from plant materials.

  • Biodegradable plastics.

  • Glass, paper, and reusable metal containers.

• Societal Solutions to Plastic Pollution:

  • Reduce plastic demand overall.

  • Boost recycling efforts.

  • Research biodegradable alternatives.

  • Improve waste management systems.

  • Support sustainable product initiatives.

• Personal Actions to Address Plastic Pollution:

  • Reduce use of single-use plastics.

  • Engage in proper recycling practices.

  • Utilize reusable products wherever feasible.

  • Support companies with environmentally responsible practices.

Composition of Bioplastics

• Materials Used for Bioplastics:

  • Made from renewable biological materials such as:

  • Corn starch

  • Sugarcane

  • Potato starch

  • Vegetable oils

• Potential Benefits of Bioplastics:

  • Reduction of reliance on fossil fuels.

  • Diminished carbon emissions.

  • Some types are biodegradable.

  • Reduction of overall plastic pollution.

• Environmental Friendliness of Bioplastics:

  • More environmentally friendly than conventional plastics, but require industrial composting for proper breakdown.

• Composting Process for Bioplastics:

  • Breakdown facilitated by microbial activity in controlled composting environments, resulting in water, carbon dioxide, and organic matter.

• Properties of Plastics:

  • Characteristics include:

  • Lightweight

  • Durable

  • Flexible

  • Resistant to water and chemicals.

• Leachate:

  • Definition: Contaminated liquid produced when water passes through waste, extracting soluble chemicals (often seen in landfills).

Environmental Impacts and Solutions Related to Plastics

• Biodegradability of Bioplastics:

  • Some are biodegradable; however, many necessitate specific industrial conditions to decompose effectively.

• Impact of Plastics on Marine Life:

  • Risks include ingestion, leading to starvation, and entanglement in plastic debris.

  • Plastics can leach harmful chemicals into aquatic systems.

• Plastic Waste Reduction Strategies:

  • Utilize reusable alternatives.

  • Avoid single-use plastic products.

  • Participate in proper recycling.

  • Seek out products with minimal packaging.

Tools and Instruments Used During the Lab Course

• Lab Tools and Their Uses:

  • Measuring Tape: Measures length or distance.

  • Measuring Wheel: Used for measuring long distances on the ground.

  • Balances: Determines the mass of an object.

  • Thermometers: Measures temperature.

  • Forceps: Facilitates the picking up of small objects.

  • Serological Pipets: Measures and transfers precise liquid volumes.

  • Pipet Pumps: Device to control liquid transfer in pipettes.

  • Transfer Pipets: Moves small amounts of liquid.

  • Graduated Cylinders: Measures liquid volume accurately.

  • Rulers: Measures short distances or lengths.

  • Petri Dishes: Culturing microorganisms or growing samples.

  • Parafilm: Flexible film used to seal containers.

  • Fixed Pipettes: Dispenses a specific volume of liquid.

  • Pipette Tips: Disposable tips attached to pipettes.

  • UV Meter: Measures ultraviolet radiation intensity.

  • Power Meter: Measures electrical energy usage.

Practice Questions

1. Convert the following measurements, showing work for full credit:

   • a. 250 centimeters to meters:

     • $100 cm = 1 m$; therefore, $250 ÷ 100 = 2.5 m$.

     • Answer: 250 cm = 2.5 m.

   • b. 2.5 kilograms to grams:

     • $1 kg = 1000 g$; therefore, $2.5 \times 1000 = 2500 g$.

     • Answer: 2.5 kg = 2500 g.

   • c. 3000 grams to kilograms:

     • $1000 g = 1 kg$; therefore, $3000 ÷ 1000 = 3 kg$.

     • Answer: 3000 g = 3 kg.

   • d. 1.2 liters to milliliters:

     • $1 L = 1000 mL$; therefore, $1.2 \times 1000 = 1200 mL$.

     • Answer: 1.2 L = 1200 mL.

   • e. 500 milliliters to liters:

     • $1000 mL = 1 L$; therefore, $500 ÷ 1000 = 0.5 L$.

     • Answer: 500 mL = 0.5 L.

   • f. Convert 210 Fahrenheit to Celsius:

     • Formula: $°C = (°F - 32) \times \frac{5}{9}$;

     • $210 - 32 = 178$;

     • $178 \times 5 = 890$;

     • $890 ÷ 9 = 98.9$.

     • Answer: 210°F ≈ 98.9°C.

2. Average Books Read by Students:

   • Analyze the dataset capturing the reading habits in a classroom over six months:

     • Average Calculation:

     • Alice: 24 books over 6 months = 4 books/month.

     • Bob: 30 books = 5 books/month.

     • Charlie: 24 books = 4 books/month.

     • Dana: 18 books = 3 books/month.

     • Ethan: 36 books = 6 books/month.

     • A bar graph is the suitable representation:

     • X-axis: Students

     • Y-axis: Average books read

     • Caption: Average number of books read by students over a six-month period.
       Ethan read the most books on average, while Dana read the fewest.

3. Design an Experiment for Onion Plants:

   • Independent Variable: Presence of onion extract.

   • Dependent Variable: Seed germination rate or seedling growth.

   • Controlled Variables: Same seed type, soil type, water amount, light exposure, and temperature.

   • Control Group: Seeds grown without onion extract (just water).

   • Experimental Group: Seeds exposed to onion extract solution.

   • Replication: 3–5 replicates per group is necessary for reliable results.

4. Identify Parts of a Scientific Paper:

   • Analyze an excerpt and determine the related section based on context.

   • Write out three to five keywords that succinctly describe the focus of the research.

5. Define Green Buildings:

   • A green building is engineered to diminish environmental impact and enhance energy efficiency via sustainable practices.

   • Advantages: Lower energy consumption, less pollution, healthier air quality.

   • Disadvantages: Higher initial costs, limited material availability, specialized knowledge required.