Science at Don Valley

1. AQA GCSE - How Science Works Science at Don Valley Glossary Accuracy How close a measurement is to its true value.

2. AQA GCSE - How Science Works Glossary Calibration Marking a scale on a measuring instrument. This involves establishing the relationship between indications of measurement and standard/reference quantity values (placing a thermometer in ice to see if it reads zero to check if it has been calibrated correctly).

3. AQA GCSE - How Science Works Science at Don Valley Glossary Data Information, either qualitative or quantitative, that has been collected. Evidence Data which has been shown to be valid.

4. AQA GCSE - How Science Works Science at Don Valley Glossary Measurement errors The difference between a measured value and the true value.

5. AQA GCSE - How Science Works Science at Don Valley Glossary Anomalies Results that are different to the pattern or trend. These are often caused by errors or unfair testing. They should be ignored in the calculation of a mean.

6. AQA GCSE - How Science Works Science at Don Valley Glossary Random errors These cause readings to spread about the true value, are present during any measurement, and cannot be corrected. They can be reduced by making more measurements and calculating a new mean.

7. AQA GCSE - How Science Works Science at Don Valley Glossary Systematic errors These cause readings to differ from the true value by a consistent amount by the environment, method of observation or instruments used. Remove these errors by repeating the data collection using a different technique or set of equipment, and then comparing the results.

8. AQA GCSE - How Science Works Science at Don Valley Glossary Zero error When a measuring instrument gives a false reading when the true value of a measured quantity is zero (the needle on an ammeter failing to return to zero when no current flows). This may lead to a systematic error.

9. AQA GCSE - How Science Works Science at Don Valley Glossary A fair test An investigation or experiment where only the independent variable has been allowed to affect the dependent variable. This means only changing one variable and keeping everything else the same.

10. AQA GCSE - How Science Works Science at Don Valley Glossary Hypothesis A proposal intended to explain facts or observations. Prediction What will happen in the future – based on observation, experience or a hypothesis.

11. AQA GCSE - How Science Works Science at Don Valley Glossary Interval The quantity between readings. (e.g. A set of 11 readings equally spaced over a distance of 1 metre would give an interval of 10 centimetres).

12. AQA GCSE - How Science Works Glossary Precision Precise measurements are ones in which there is very little spread about the mean value. Precision depends only on the extent of random errors – it gives no indication of how close to the true value.

13. AQA GCSE - How Science Works Science at Don Valley Glossary Range The maximum and minimum values of the independent or dependent variables. (e.g. A range of distances may be either: ‘From 10cm to 50cm’ or ‘From 50cm to 10cm’).

14. AQA GCSE - How Science Works Science at Don Valley Glossary Repeatable A measurement is repeatable if the original experimenter repeats the investigation using the same method and equipment and obtains the same results.

15. AQA GCSE - How Science Works Science at Don Valley Glossary Reproducible A measurement is reproducible if the investigation is repeated by another person, or by using different equipment or techniques, and the same results are obtained.

16. AQA GCSE - How Science Works Science at Don Valley Glossary Resolution This is the smallest change in the quantity being measured (input) of a measuring instrument that gives a perceptible change in the reading.

17. AQA GCSE - How Science Works Science at Don Valley Glossary Sketch a graph A line graph, not necessarily on a grid, showing the relationship between two variables. No plots or scales used, but axes labelled.

18. AQA GCSE - How Science Works Science at Don Valley Glossary True value This is the value that would be obtained in an ideal experiment.

19. AQA GCSE - How Science Works Science at Don Valley Glossary Uncertainty The interval within which the true value can be expected to lie, with a given level of confidence or probability. (e.g. The temp. is 20°C ± 2°C)

20. AQA GCSE - How Science Works Science at Don Valley Glossary Validity Data is only valid if the measurements taken are affected by a single independent variable only. To get valid results you need to carry out a fair test.

21. AQA GCSE - How Science Works Science at Don Valley Glossary Categoric variables Variables that are labels (names of plant or types of material). You should use a bar chart to show this type of data.

22. AQA GCSE - How Science Works Science at Don Valley Glossary Continuous variables Variables that can have values (quantity) by counting (number of shrimp) or by measurement (light intensity). You should use a line graph to show this type of data.

23. AQA GCSE - How Science Works Science at Don Valley Glossary Dependent variable The variable that you measure for each and every change in the independent variable.

24. AQA GCSE - How Science Works Science at Don Valley Glossary Independent variable The variable you change or select to investigate.