Data are facts, numbers, or observations that we collect during experiments. In physics, data can include:

• Measurements (like length, time, temperature, current, voltage)
• Observations (like colour, position, or whether an object is attracted to a magnet)
• Recordings from instruments (like ammeter readings or light meter readings)

Analysing data means organizing, interpreting, and drawing conclusions from the data to explain physical quantities.

Step 1: Identify the Physical Quantity

Decide which quantity you are investigating:

• Light: brightness, angle of reflection, shadow size
• Magnetism: attraction or repulsion, strength of magnet
• Static electricity: amount of charge, attraction force
• Current electricity: current, voltage, resistance

Step 2: Plan Your Data Collection

• Decide what to measure or observe
• Choose appropriate tools (ruler, ammeter, voltmeter, compass)
• Determine units (metres, amperes, volts)
• Record data in a table

Step 3: Collect Data Carefully

• Take multiple readings for accuracy
• Record units with each value
• Note any observations that are not numbers

Step 4: Analyse the Data

• Look for patterns or trends
• Calculate averages if you have multiple readings
• Compare results with expected values
• Draw conclusions about the physical quantity

What to Collect

• Shadow lengths at different times of day
• Angle of incidence and angle of reflection
• Distance from light source and brightness

Example Data Table

How to Analyse

Calculate the average brightness and observe: As distance increases, brightness decreases. This explains that light intensity is a physical quantity that follows the inverse square law — the farther away, the weaker the light.

What to Collect

• Which materials are attracted to a magnet
• How many paper clips a magnet can hold at different distances
• Direction of compass needle near a magnet

Example Data Table

How to Analyse

Group the results: Magnetic materials (iron, steel) are attracted; non-magnetic materials (aluminium, copper) are not. This data explains that magnetism is a property of certain metals, specifically iron and its alloys.

What to Collect

• Whether a charged object attracts light materials
• Which materials can be charged by rubbing
• Distance at which attraction occurs

Example Data Table

How to Analyse

Observe the pattern: Charged objects attract light materials regardless of the material. This data explains that static electricity creates an electric force that can attract neutral objects.

What to Collect

• Current (A) flowing in a circuit
• Voltage (V) across components
• Resistance (Ω) of different components

Example Data Table

How to Analyse

Calculate resistance using Ohm's Law: $R = \frac{V}{I}$

• Resistor: $R = \frac{6.0}{0.5} = 12 \Omega$
• Bulb: $R = \frac{6.0}{0.3} = 20 \Omega$
• Wire: $R = \frac{6.0}{0.6} = 10 \Omega$

Conclusion: Different components have different resistances. The bulb has the highest resistance, which is why less current flows through it at the same voltage.

A Form 2 student in Dar es Salaam collected the following data while investigating a simple circuit with a 9V battery:

Step 1: Calculate the average current $I_{avg} = \frac{0.30 + 0.31 + 0.29}{3} = \frac{0.90}{3} = 0.30 A$

Step 2: Calculate the resistance $R = \frac{V}{I} = \frac{9.0}{0.30} = 30 \Omega$

Step 3: Conclusion The resistor has a resistance of 30 ohms. The small differences in current readings (0.29–0.31 A) show that experimental readings have slight variations, but the average gives a reliable value.

1. Always use tables to organize your data clearly
2. Include units with every measurement
3. Take multiple readings and calculate averages
4. Look for patterns — trends, relationships, or groupings
5. Compare results with what you expected to find
6. Draw conclusions that directly answer your original question

• Recording data without units
• Taking only one reading and claiming it is accurate
• Forgetting to label rows and columns in tables
• Drawing conclusions that do not match the data

In Tanzania, electricians and technicians use data collection and analysis skills daily. For example, when installing solar panels in rural areas like Mbeya or Arusha, a technician measures the voltage and current from the panel using a multimeter and records the data to calculate if the system can power a household's lights and phone charging. By analysing these measurements, they determine whether the solar setup is sufficient or needs additional panels — directly applying the same data analysis skills learned in physics class.