Laboratory work is where scientific theory meets practice. Whether you're in biology, chemistry, physics, or engineering, strong lab skills are essential for research, internships, and careers in STEM. Here's how to develop the technical competence, safety awareness, and problem-solving mindset that make great lab scientists.
Why Lab Skills Matter
1. Hands-on application: Theory is abstract; lab work makes concepts tangible.
2. Research opportunities: Professors hire undergrads with strong lab skills for research projects.
3. Career readiness: Industry and grad school value practical lab experience.
4. Problem-solving: Experiments rarely go as planned—lab work teaches troubleshooting and critical thinking.
Foundational Lab Skills
Safety First
Before entering any lab:
- Complete required safety training
- Know the location of safety equipment (eyewash stations, fire extinguishers, spill kits, emergency exits)
- Understand chemical hazards (read MSDSs - Material Safety Data Sheets)
- Wear appropriate PPE (personal protective equipment): lab coat, goggles, gloves, closed-toe shoes
Golden rules:
- Never eat, drink, or apply cosmetics in the lab
- Never pipette by mouth (always use a pipette bulb or electronic pipette)
- Dispose of waste properly (chemical, biological, sharps, glass—each has specific protocols)
- Report all spills, injuries, and equipment malfunctions immediately
If in doubt, ask: Better to ask a "dumb" question than cause an accident.
Accurate Measurement
Precision matters. Small errors in measurement compound into large errors in results.
Mass measurement:
- Use analytical balances for precise measurements (± 0.0001 g)
- Tare (zero) the balance before use
- Avoid air currents and vibrations (close the draft shield on analytical balances)
Volume measurement:
- Graduated cylinder: ± 1 mL (good for approximate volumes)
- Volumetric flask: ± 0.1 mL (precise for preparing solutions)
- Pipette: ± 0.01 mL (most precise, use for critical measurements)
- Burette: ± 0.05 mL (for titrations)
Read the meniscus: Liquid in glassware forms a curve. Read the bottom of the meniscus at eye level.
Record-Keeping
A lab notebook is your scientific record. It must be clear, detailed, and reproducible.
What to record:
- Date and objective
- Detailed procedure (enough detail that someone else could replicate your work)
- Observations (qualitative: color changes, precipitation, odors)
- Raw data (masses, volumes, times, temperatures)
- Calculations (show all work, including units)
- Results and conclusions
- Sources of error
Best practices:
- Write in pen (never pencil—prevents tampering)
- Don't erase; cross out mistakes with a single line
- Date and sign each entry
- Number pages
- Use tables and diagrams where helpful
Intermediate Lab Skills
Solution Preparation
Making solutions of precise concentration is a fundamental skill.
Molarity (M): Moles of solute per liter of solution.
Example: Prepare 500 mL of 0.1 M NaCl.
1. Calculate moles needed: 0.1 M × 0.5 L = 0.05 mol
2. Convert to grams: 0.05 mol × 58.44 g/mol = 2.922 g
3. Weigh 2.922 g NaCl
4. Dissolve in ~400 mL DI water
5. Transfer to 500 mL volumetric flask
6. Add water to the 500 mL mark
Pipetting Techniques
Accurate pipetting is essential for quantitative experiments.
Micropipettes (1-1000 μL):
- Select correct volume range
- Attach tip firmly
- Pre-wet tip
- Hold pipette vertically
- Use slow, controlled movements
- Change tips between samples
Spectroscopy
Measures light absorption to identify or quantify substances.
UV-Vis spectrophotometry:
- Measures absorbance at specific wavelengths
- Beer-Lambert Law: A = εbc
- Used to determine concentration
Procedure:
1. Blank the instrument
2. Measure absorbance of standards
3. Create calibration curve
4. Measure unknown sample
5. Determine concentration
Advanced Lab Skills
PCR (Polymerase Chain Reaction)
Amplifies specific DNA sequences.
Steps:
1. Denaturation (94-96°C): Separate DNA strands
2. Annealing (50-65°C): Primers bind to target
3. Extension (72°C): Polymerase synthesizes new DNA
Cycles: Repeat 25-40 times → exponential amplification.
Gel Electrophoresis
Separates DNA, RNA, or proteins by size using an electric field.
DNA/RNA gel electrophoresis:
- Agarose gel
- Load samples in wells
- Apply electric field
- Smaller fragments migrate faster
- Visualize under UV light
Cell Culture
Growing cells in vitro for research.
Key considerations:
- Sterile technique
- Nutrient-rich media
- 37°C, 5% CO₂ incubation
- Regular passaging
Troubleshooting Experimental Problems
Experiments fail. Developing troubleshooting skills is critical.
Common issues:
- No signal/unexpected results → Check reagents, equipment, procedure
- Contamination → Review sterile technique
- Inconsistent replicates → Improve technique, control variables
- Equipment malfunction → Check settings, consult manual
Final Thoughts
Lab skills are learned through practice, observation, and mentorship.
Keys to success:
- Safety always
- Attention to detail
- Thorough record-keeping
- Ask questions
- Practice consistently
- Stay curious
Strong lab skills open doors to research opportunities, internships, and careers in STEM.
