Starter quiz
- Which piece(s) of laboratory equipment are typically used for measuring volume?
- Graduated cylinder (measuring cylinder) ✓
- Balance
- Pipette ✓
- Ruler
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- Which mathematical operation(s) would you use to calculate the average of three measurements?
- Addition ✓
- Subtraction
- Multiplication
- Division ✓
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- In an experiment, what type of variable is the one that the scientist changes?
- Independent variable ✓
- Dependent variable
- Control variable
- Uncontrolled variable
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- In an experiment measuring the effect of sunlight on plant growth, what is the dependent variable?
- The type of plant.
- The amount of water given to each plant.
- The height of the plant. ✓
- The amount of sunlight each plant receives.
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- Significant ______ refer to the digits in a measurement that are known with certainty plus the first digit that is uncertain.
- 'figures' ✓
- Match the following terms with their correct definitions:
- Random Error⇔An error that has an equal probability of being too high or too low. ✓
- Precision⇔The closeness of two or more measurements to each other. ✓
- Accuracy⇔The degree to which a measurement reflects the true value. ✓
- Control Variable⇔A variable that is kept constant throughout an experiment. ✓
Exit quiz
- What does the uncertainty of a measurement indicate?
- The exact value of the measurement.
- The precision of the apparatus.
- The range within which the true value can be found. ✓
- The number of measurements taken.
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- Match the term to its correct definition.
- Measurement⇔Quantitative information about an object or system. ✓
- Uncertainty⇔The range within which the true value can be found. ✓
- Mean⇔An average calculated from a set of values. ✓
- Resolution⇔The smallest change a piece of apparatus can measure. ✓
- Apparatus⇔A piece of equipment designed for a particular use. ✓
- How does a higher resolution affect the uncertainty of a measurement?
- Increases the uncertainty.
- Decreases the uncertainty. ✓
- Has no effect on uncertainty.
- Makes the measurement less accurate.
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- ______ is the range of measurements within which the true value can be expected to be found. It reflects the limitations of our measuring devices.
- 'uncertainty' ✓
- The resolution of a measuring device is 0.02 g. What is the uncertainty of an individual measurement?
- 0.01 g ✓
- 0.02 g
- 0.04 g
- 0.1 g
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- Why is it important to consider the choice of equipment when conducting measurements?
- Equipment choice has no impact on the outcome.
- Different equipment can yield different levels of precision. ✓
- Better equipment always guarantees the correct value.
- Equipment choice affects the colour of the data.
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Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- Whenever a measurement is made, there is always some uncertainty about the result obtained.
- The uncertainty of an individual measurement is equal to half the resolution of the device used to take the measurement.
- The higher the resolution, the lower the uncertainty of an individual measurement.
- Half the range of repeated measurements equals the uncertainty of a mean value.
- The uncertainty of a measurement provides a range within which the actual value can be found.
Common misconception
Pupils rarely consider the choice of equipment and its link to the accuracy of the data they collect in a practical.
Highlight that equipment with smaller resolution provides more precise measurements, which can decrease the uncertainty of a calculated mean.
Keywords
Uncertainty - is the range of measurements within which the true value can be expected to be found. On apparatus, it is half the value of one resolution marking.
Measurement - provides quantitative information about an object or system.
Mean - is an average calculated by adding up the values of a set of measurements and dividing by the number of measurements in the set.
Resolution - is the smallest change a piece of apparatus can measure - shown by its markings.
Apparatus - a piece of equipment that is designed for a particular use.
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