Scientific Enquiry - Data Collection and Measurement

Variables: In a scientific investigation, the Independent Variable is the one you change, the Dependent Variable is the one you measure, and Control Variables are those kept constant to ensure a fair test.

Types of Data: Quantitative data involves numerical measurements (e.g., $25.5\text{ g}$), while Qualitative data describes qualities or characteristics (e.g., 'the liquid turned blue').

Measuring Length: Standard SI unit is the meter ($m$). For smaller objects, we use centimeters ($cm$) or millimeters ($mm$). Always align the $0$ mark of the ruler with the start of the object.

Measuring Volume: Measured in cubic centimeters ($cm^3$) or milliliters ($ml$). When using a measuring cylinder, always read the value at the bottom of the meniscus (the curve of the liquid) at eye level.

Measuring Mass: Measured in grams ($g$) or kilograms ($kg$) using a digital balance. Always 'tare' or 'zero' the balance before starting.

Measuring Temperature: Measured in degrees Celsius ($^\circ\text{C}$) using a thermometer. Ensure the bulb is fully submerged in the substance but not touching the container walls.

Precision and Accuracy: Accuracy refers to how close a measurement is to the true value, while precision refers to how close repeated measurements are to each other.

Reliability: To improve reliability, experiments should be repeated at least three times and a Mean (average) should be calculated to reduce the impact of anomalous results.