PH01-01 Physics Watch
Units, prefixes and standard form in physics
Subscribe on YouTubeLike this lesson on YouTube
In this lesson
In this video you'll learn about units, prefixes and standard form for GCSE Physics. Video code: PH01-01 - search YouTube for "ScholaFly PH01-01" to come straight back to this video.
By the end: Convert a measurement into its SI unit using the prefixes from nano to giga, and state the result in standard form to the number of significant figures the question asks for.
What it covers
- The SI units a GCSE physicist actually meets - metre, kilogram, second, ampere, kelvin, and the derived newton, joule, watt and volt - introduced as QUANTITY, SYMBOL, UNIT in that order
- The prefixes nano, micro, milli, centi, kilo, mega and giga, each with its power of ten
- Converting from a prefixed unit into its SI base: kW to W, mm to m, g to kg, MHz to Hz, nm to m
- Converting back the other way, from the SI base into a prefixed unit, which is the direction students practise least
- Converting hours and minutes into seconds, and seconds back into hours
- Standard form: writing a number as a figure between 1 and 10 multiplied by a power of ten, and reading a calculator display that has already done it for you
- Significant figures: rounding a FINAL answer to a stated number, keeping the power of ten attached, and rounding at the end rather than partway through
- The habit that carries the rest of the course: convert BEFORE substituting, and show the unit on every line
Key words
For: Edexcel GCSE 1PH0, OCR GCSE J249
On the specification
| Board | Spec | Statement |
|---|---|---|
| Edexcel GCSE 1PH0 | 1.1 | Recall and use the SI unit for physical quantities, as listed in Appendix 3 |
| Edexcel GCSE 1PH0 | 1.2 | Recall and use multiples and sub-multiples of units, including giga (G), mega (M), kilo (k), centi (c), milli (m), micro (μ) and nano (n) |
| Edexcel GCSE 1PH0 | 1.3 | Be able to convert between different units, including hours to seconds |
| Edexcel GCSE 1PH0 | 1.4 | Use significant figures and standard form where appropriate |
| OCR GCSE J249 | P2.1c | Make calculations using ratios and proportional reasoning to convert units and to compute rates |
| OCR GCSE J249 | P8.1c | Make calculations using ratios and proportional reasoning to convert units and to compute rates |
For teachers
This GCSE Physics lesson teaches units, prefixes and standard form in physics. By the end, students should be able to convert a measurement into its SI unit using the prefixes from nano to giga, and state the result in standard form to the number of significant figures the question asks for. It works through four worked examples and the mistakes examiners report, and suits Foundation and Higher tier students.