Use of appropriate apparatus to make and record a range of measurements…

The idea

Accurate practical work depends on choosing the right instrument for each quantity and recording readings with sensible precision. Use a ruler or metre rule for length in millimetres or centimetres, and calculate area from measured lengths, for example length × width for a rectangle, giving cm² or m². Use a balance for mass in grams or kilograms, a stopwatch or timer for time in seconds, a measuring cylinder or burette for volume in cm³ or ml, and a thermometer for temperature in degrees Celsius. Read scales at eye level to avoid parallax error, note the smallest division to judge precision, and repeat readings where possible. Record every value with its unit and an appropriate number of significant figures.

What earns the marks

• Selects a ruler or metre rule for length and records the value with a unit such as cm or mm.
• Calculates area from measured lengths, for example multiplying length by width for a rectangle.
• Uses a balance for mass and records it in grams or kilograms.
• Uses a stopwatch or timer for time and records it in seconds.
• Reads a measuring cylinder at eye level and records volume in cm³ or ml.
• Uses a thermometer for temperature and records it in degrees Celsius.

Common mistakes and how to put them right

• Reads a measuring cylinder scale from above or below eye level.

  Put it right: View the meniscus at eye level to avoid parallax error.

• Records a measurement without a unit.

  Put it right: Attach the correct unit to each value.

• Chooses a stopwatch to measure length.

  Put it right: Match each instrument to the quantity it measures.

Exam tips

• State the instrument and the unit together, for example 'metre rule, length in cm'.
• Quote readings to the precision of the smallest scale division rather than adding extra digits.
• Repeat a measurement and average the results to reduce random error.