The Practical Assessment for the WJEC Applied Science (Single Award) evaluates students' ability to apply scientific knowledge through hands-on experiments. It focuses on key skills such as planning investigations, collecting accurate data, analyzing results, and writing scientific reports. This assessment provides an opportunity to demonstrate proficiency in handling scientific equipment and interpreting findings in real-world contexts. They must also critically evaluate their methods and results to suggest improvements. Overall, the Practical Assessment is a crucial component that showcases a student’s practical and analytical capabilities in applied science.

1. Experimental Design and Variables

The experimental design refers to the structured process of planning and conducting experiments. It ensures that results are reliable, reproducible, and valid. There are stages that are included in the experimental design such as Aim, Hypothesis, Materials and Equipment, Procedure/Method, Data Collection, and Risk Assessment.

• Aim - The purpose of the investigation, usually framed as a question or a hypothesis that the experiment aims to test.

• Hypothesis - A predictive statement based on prior knowledge or observations, which can be tested through experimentation.

• Materials and Equipment - A list of all necessary tools and materials required to conduct the experiment.

• Procedure/Method - A detailed, step-by-step guide on how to carry out the experiment, ensuring it can be replicated. This part should be clear and concise, showing how to manipulate variables and measure results.

• Data Collection - The process of gathering measurable evidence or observations during the experiment. Data is often recorded in tables or charts for clarity.

• Risk Assessment - Identification of potential hazards and how to minimize them during the experiment.

Variables in Practical Assessment

• Independent Variable - This is the variable that the experimenter changes or manipulates to observe its effect on the dependent variable. It is the cause in a cause-and-effect relationship. For example, if testing the effect of temperature on enzyme activity, the temperature is the independent variable.

• Dependent Variable - This is the variable that is measured during the experiment. It is the effect that occurs due to changes in the independent variable. Continuing with the enzyme example, the rate of enzyme activity would be the dependent variable.

• Controlled Variables (Constant Variables) - These are variables that are kept constant throughout the experiment to ensure that any changes in the dependent variable are due solely to changes in the independent variable. For example, if you are testing enzyme activity at different temperatures, you might control the pH and enzyme concentration.

2. Types of Scientific Investigations

This explores various types of scientific investigations as part of practical assessment. These investigations, which include controlled experiments, field studies, and observational research, help students develop key skills in data collection and analysis. By manipulating variables and analyzing their effects, learners can investigate concepts such as chemical reactions and rates of reaction. Each investigation type offers unique insights into scientific phenomena and helps build a solid foundation for real-world applications in science.

a. Controlled Investigations

Focuses on testing the effect of one variable while keeping all other factors constant. Manipulating an independent variable and measuring its impact on the dependent variable, ensuring that any changes are due to this single factor. This method allows for precise, repeatable experiments, enabling students to draw clear conclusions about cause-and-effect relationships in scientific phenomena. Controlled investigations are characterized by the following:

• Aim/Hypothesis: The investigation has a clear hypothesis or aim that guides the experiment.

• Independent Variable: Only one variable is changed to observe its effect on another.

• Dependent Variable: This is the outcome that is measured.

• Controlled Variables: All other factors are kept constant to ensure that the results are due to the change in the independent variable.

b. Field Investigations

Field investigations are carried out in natural settings rather than controlled environments such as laboratories. These investigations allow scientists to study real-world phenomena in their natural context. Key characteristics include:

• Natural Environment: Observations and measurements are taken in natural or outdoor settings.

• Minimal Control of Variables: In a field setting, it may be difficult or impossible to control all variables, so investigators must account for these in their analysis.

• Challenges: The unpredictability of natural environments, weather conditions, and the presence of uncontrolled variables can make these investigations complex.

c. Observational Studies

Observational studies involve the careful monitoring and recording of behaviors, phenomena, or processes without intervening or manipulating variables. This type of investigation is useful when it’s unethical or impractical to conduct controlled experiments. Characteristics include:

• Non-intrusive: The investigator does not intervene or alter the environment or subjects.

• Data Collection: Information is gathered through detailed observation over a period.

• Limitations: As there is no manipulation of variables, establishing cause-and-effect relationships can be difficult.

d. Comparative Investigations

Comparative investigations involve comparing two or more groups, conditions, or variables to identify similarities and differences. These types of investigations are often used when it's difficult or impossible to control variables as in a controlled experiment.

• Multiple Groups or Variables: Two or more scenarios are compared without directly manipulating variables.

• Purpose: To identify trends, differences, or correlations between groups.

• Limitations: As with observational studies, causality is harder to determine.

e. Modelling Investigations

Modelling investigations involve creating models to simulate scientific phenomena or processes that are too complex, large, or impractical to study directly. These models can be physical representations, computer simulations, or mathematical models.

• Simplified Representations: Models are simplified versions of real systems.

• Prediction and Testing: Models allow scientists to predict outcomes based on different variables.

• Benefits: Models allow the study of complex systems in a manageable way.

• Challenges: Models are simplifications, so they may not account for all real-world variables.

f. Surveys and Questionnaires

In some scientific investigations, data is collected through surveys or questionnaires, especially in fields related to human behavior, health, or opinions. These studies involve gathering information from individuals or groups to analyze trends, patterns, or correlations.

• Large Data Sets: Surveys can collect data from a large number of participants.

• Statistical Analysis: Data from surveys are often analyzed statistically to find patterns or relationships.

• Limitations: Surveys rely on self-reported data, which can be biased or inaccurate.

g. Case Studies

A case study involves an in-depth investigation of a single instance or event, focusing on detailed and specific data collection and analysis. This focuses on one particular case or instance, offering in-depth insight and is useful in fields like medicine, psychology, and environmental science.

h. Topics

I. Chemical Reactions and Rates of Reaction

• Concepts: Reaction rates, catalysts, temperature effects, concentration, surface area.

• Common Experiments:

  • Measuring how quickly a product (like gas) forms in a reaction.

  • Investigating the effect of temperature on the rate of reaction (e.g., dissolving sugar in water).

II. Energy and Electricity in Physics

• Concepts: Energy transfers, efficiency, electrical circuits, Ohm’s law, resistance.

• Common Experiments:

  • Investigating how the length of a wire affects its resistance.

  • Measuring the efficiency of a simple machine or energy transfer in a system.

  • Using a voltmeter and ammeter to determine the relationship between voltage, current, and resistance.

III. Biological Experiments

• Concepts: Photosynthesis, respiration, enzyme activity, cell structure.

• Common Experiments:

  • Testing the effect of light intensity on the rate of photosynthesis in pondweed.

  • Investigating enzyme activity (e.g., amylase breaking down starch).

  • Observing osmosis using potato cylinders in different concentrations of sugar solution.

3. Data Collection and Analysis

Gathering accurate and reliable data from experiments, using various tools and techniques to ensure precise measurements. Once the data is collected, it is analyzed to identify patterns, trends, and relationships, helping students understand the scientific principles at play. This process enables learners to draw informed conclusions and evaluate the validity and reliability of their investigations.

a. Data Collection

• Accurate Measurement - Collecting data using various tools and equipment, such as thermometers, balances, and burettes. Accuracy is crucial for reliable results, so students must calibrate equipment and follow precise measurement techniques.

• Recording Data - Data should be recorded systematically in tables or charts. Observations, numerical measurements, and qualitative data should be clearly noted, including units of measurement.

• Repetition and Reliability - To ensure reliability, experiments should be repeated multiple times. This helps in identifying consistent trends and minimizing the impact of random errors.

• Handling Anomalies - Anomalies or unexpected results should be noted and investigated. It is necessary to assess whether these are due to experimental errors, equipment malfunctions, or other factors.

• Ethical and Safety Considerations - Data collection must adhere to safety guidelines and ethical standards. Proper handling of chemicals, biological materials, and equipment is essential to ensure safety and accuracy.

b. Data Analysis

• Organizing Data - Data is organized into tables or graphs for easier interpretation. Tables should have clear headings and units, while graphs should be appropriately labeled with the independent variable on the x-axis and the dependent variable on the y-axis.

• Interpretation - Analyze data to identify trends, patterns, and relationships. This involves looking for correlations between variables and determining if the results support the hypothesis.

• Statistical Analysis - Basic statistical methods, such as calculating the mean, median, range, and standard deviation, may be used to summarize data. Statistical tools help in assessing the significance of the results and the reliability of the findings.

• Drawing Conclusions - Based on the analysis, students draw conclusions about the scientific question or hypothesis. They must evaluate whether the data supports the hypothesis and consider the implications of their findings.

c. Practical Applications

• Use of Graphs and Charts - Graphs and charts are essential for visualizing data. Common types include line graphs for continuous data, bar charts for categorical data, and scatter plots for showing relationships between variables.

• Error Analysis - Identifying and analyzing potential errors, including systematic and random errors, is a critical part of the analysis. Students should discuss how these errors might have affected the results and how they could be minimized.

• Comparison with Theory - Comparing experimental results with theoretical predictions helps in understanding how well the experimental data fits known scientific principles or models.

4. Common Scientific Equipment

Familiarity with common scientific equipment is essential for effective practical assessments. Students use a variety of tools to accurately measure and observe experimental variables. Understanding how to properly use and maintain this equipment ensures reliable data collection and precise results. Mastery of these tools helps conduct experiments efficiently and draw valid conclusions from their investigations.

a. Measuring Tools

• Thermometer - It measures temperature in degrees Celsius (°C) or Fahrenheit (°F). It is essential for experiments involving temperature changes, such as studying reaction rates or thermal properties.

• Balance - This measures mass in grams (g) or kilograms (kg) and is used for measuring the mass of solids, liquids, or powders accurately.

• Graduated Cylinder - Measures the volume of liquids. It provides accurate liquid measurements, typically in milliliters (mL) or liters (L).

• Pipette - Transfers a precise volume of liquid and is essential for experiments requiring accurate liquid volumes, such as titrations.

• Burette - Dispenses variable volumes of liquid with precision. Commonly used in titrations to add reagent slowly and accurately.

• Volumetric Flask - Prepares solutions of precise volumes and is used for preparing standard solutions where exact volume is crucial.

b. Glassware

• Beaker - Contains, mixes, and heats liquids. It is suitable for general purposes but less accurate for measuring volumes.

• Conical Flask (Erlenmeyer Flask) - Mixes and heats liquids, minimizes spillage. Useful for swirling liquids without risk of splashing.

• Test Tubes - Holds small quantities of substances for observation and reactions. Is commonly used for small-scale reactions and qualitative tests.

• Watch Glass - Covers beakers or holds small samples for evaporation and used for heating, sterilization, and combustion in various experiments.

c. Heating Equipment

• Bunsen Burner - Provides a controlled flame for heating substances. Used for heating, sterilization, and combustion in various experiments.

• Hot Plate - Provides a flat surface for heating liquids. Useful for heating solutions without an open flame.

• Water Bath - Provides a stable, controlled temperature environment. Used for heating substances gently and uniformly.

5. Safety in Practical Work

Ensuring safety in practical work is paramount for conducting experiments effectively and responsibly. Students must adhere to established safety protocols to prevent accidents and manage risks associated with handling chemicals, equipment, and other materials. Proper use of safety equipment, such as goggles and lab coats, is essential to protect themselves and others. By following safety guidelines and procedures, students can focus on learning and discovering scientific principles while maintaining a secure laboratory environment.

a. General Safety Guidelines

I. Understanding Risks

• Assessment: Before starting an experiment, students must assess potential risks associated with chemicals, equipment, and procedures.

• Information: Read Material Safety Data Sheets (MSDS) or Safety Data Sheets (SDS) for information on handling and emergency procedures.

II. Personal Protective Equipment (PPE)

• Safety Goggles: Protect eyes from chemical splashes, flying particles, and intense light.

• Lab Coat: Shields clothing and skin from spills and splashes.

• Gloves: Worn to protect hands from chemicals, heat, and sharp objects.

III. Proper Lab Attire

• Clothing: Wear suitable lab attire, avoiding loose clothing and open-toed shoes.

• Hair: Long hair should be tied back to avoid contact with chemicals or equipment.

IV. Safe Conduct

• Behavior: Maintain a clean and organized workspace, avoid running or horseplay in the lab.

• Food and Drink: Never eat or drink in the laboratory to avoid contamination.

b. Handling Chemicals

I. Storage and Labeling

• Proper Storage: Store chemicals according to their specific requirements (e.g., flammable substances in safety cabinets).

• Labeling: Ensure all chemicals are clearly labeled with their name, hazard symbols, and safety information.

II. Dispensing and Mixing

• Measurement: Use appropriate tools for dispensing and measuring chemicals to avoid spills and contamination.

• Mixing: Mix chemicals according to prescribed procedures, and always add acids to water, not the other way around, to prevent exothermic reactions.

III. Spills and Accidents

• Spill Kits: Have spill kits readily available for immediate cleanup of chemical spills.

• Emergency Procedures: Know how to use eyewash stations and safety showers; follow emergency protocols for chemical exposure.

c. Equipment Safety

I. Proper Use

• Training: Receive proper training on how to use equipment like Bunsen burners, balances, and pipettes.

• Operation: Operate equipment according to manufacturer instructions and laboratory guidelines.

II. Maintenance and Inspection

• Inspection: Regularly check equipment for damage or malfunction.

• Maintenance: Perform routine maintenance and report any issues to ensure safe operation.

III. Electrical Safety

• Wiring: Ensure that electrical equipment is properly wired and maintained.

• Handling: Keep electrical cords away from water and ensure hands are dry when using electrical devices.

d. Safe Disposal of Waste

I. Waste Segregation

• Categorization: Separate waste into categories such as chemical, biological, and general waste.

• Disposal: Follow specific disposal procedures for each type of waste to avoid contamination and environmental harm.

II. Recycling

• Recycle appropriate materials according to laboratory policies to reduce environmental impact.

III. Cleanup

• Responsibility: Ensure all spills are cleaned up immediately and that workspaces are left tidy and safe.

e. Laboratory Behavior

I. Supervision

• Work under the supervision of qualified personnel or teachers who can provide guidance and ensure compliance with safety protocols.

II. Communication

• Warnings: Inform others in the lab about any potential hazards or safety concerns.

• Questions: Ask for clarification on any safety procedures or equipment use if unsure.

6. Writing the Scientific Report

A well-structured report communicates the objectives, methods, results, and conclusions of an experiment clearly and effectively. It includes sections such as the introduction, methodology, results, discussion, and conclusion, providing a comprehensive overview of the investigation. Mastering this skill helps present findings professionally and demonstrates their understanding of scientific principles and experimental procedures.

a. Structure of the Scientific Report

• Introduction: State the aim of the experiment and the scientific principles behind it.

• Method: Describe the procedure step-by-step, including materials and equipment.

• Results: Present data in tables or graphs, and summarize findings.

• Analysis: Explain the results, identify trends, and compare to your hypothesis.

• Conclusion: Summarize the findings and state whether your hypothesis was supported.

• Evaluation: Discuss reliability, accuracy, possible errors, and improvements.

b. Writing and Presentation

I. Clarity and Precision

• Language: Use clear and precise language appropriate for scientific writing.

• Detail: Ensure all descriptions are detailed enough to allow replication of the experiment.

II. Formatting

• Headings: Use headings and subheadings to organize sections and make the report easy to navigate.

• Tables and Figures: Include well-labeled tables, graphs, and figures to present data effectively.

III. Accuracy

• Proofreading: Check for grammatical errors, spelling mistakes, and ensure all data and calculations are accurate.

• Consistency: Maintain consistency in terminology, units, and formatting throughout the report.

7. Evaluation of Results

This involves analyzing the data collected during experiments to determine if it supports the hypothesis or answers the research question. Students must interpret the significance of their findings, considering factors such as accuracy, reliability, and any sources of error. A thorough evaluation helps in understanding the validity of the results and provides insights into the effectiveness of the experimental methods used.

a. Analyzing Results

I. Data Interpretation

• Patterns and Trends: Identify and describe any patterns or trends observed in the data. Look for relationships between variables and how they align with the hypothesis or research question.

• Statistical Analysis: Perform statistical calculations, such as mean, median, range, and standard deviation, to summarize and interpret data. Statistical tests may also be used to determine the significance of the results.

II. Comparing with Hypothesis

• Support for Hypothesis: Assess whether the data supports or refutes the hypothesis. Consider how well the experimental results align with the initial expectations and theoretical predictions.

III. Data Presentation

• Tables and Graphs: Use tables, graphs, and charts to present data clearly. Ensure that these visual aids are accurately labeled and include appropriate scales and units.

b. Assessing Accuracy and Reliability

I. Accuracy

• Measurement Precision: Evaluate the precision of measurements and calculations. Consider any potential errors in the data collection process and how they might affect the results.

• Consistency: Check for consistency in the results from repeated trials or experiments. Reliable results should show minimal variation if the experiment is repeated under the same conditions.

II. Reliability

• Experimental Design: Assess whether the experimental design was robust and if the methods used were appropriate for the investigation. Consider how well the experiment controlled variables and minimized potential sources of error.

• Reproducibility: Evaluate whether the results can be reproduced by other researchers or under similar conditions. Consistent results across multiple experiments or trials enhance reliability.

c. Drawing Conclusions

• Summary of Findings - Summarize the key findings of the experiment and how they relate to the hypothesis or research question. Clearly state whether the results support or refute the initial hypothesis.

• Implications - Discuss the broader implications of the findings for scientific understanding or practical applications. Consider how the results contribute to existing knowledge in the field.

• Recommendations - Suggest areas for further research or investigation based on the results and evaluation. Propose potential improvements to the experimental design or new hypotheses to explore.