Difference between revisions of "SI Unit"
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: '''SI''' stands for "Système international". | : '''SI''' stands for "Système international". | ||
: '''SI''' [[unit]]s have been standardised around the world so that any [[experiment]] can be [[reproducible|reproduced]] and so that components in machines are interchangeable. | : '''SI''' [[unit]]s have been standardised around the world so that any [[experiment]] can be [[reproducible|reproduced]] and so that components in machines are interchangeable. | ||
| − | : The USA does not always use '''SI Units'''. As a result of the confusion over [[unit]]s a space probe once crashed on [[Mars]] because one team of [[scientist]]s was using [[inch]]es and the other team was using hundredths of [[metre]] ([[centimetre]]s). | + | : The USA does not always use '''SI Units'''. As a result of the confusion over [[unit]]s a space probe once crashed on [[Mars]] because one team of [[scientist]]s was using [[inch]]es and the other team was using hundredths of [[metre]] ([[centimetre]]s) and a mistake was made converting from one to the other. |
The '''SI Units''' you should know are in the following table: | The '''SI Units''' you should know are in the following table: | ||
Revision as of 07:45, 20 April 2019
Key Stage 4
Meaning
SI Units are the standard scientific units used by scientists around the world.
About SI Units
- SI stands for "Système international".
- SI units have been standardised around the world so that any experiment can be reproduced and so that components in machines are interchangeable.
- The USA does not always use SI Units. As a result of the confusion over units a space probe once crashed on Mars because one team of scientists was using inches and the other team was using hundredths of metre (centimetres) and a mistake was made converting from one to the other.
The SI Units you should know are in the following table:
| Measurement | SI Unit |
| Distance, Displacement, Wavelength | metres |
| Time | seconds |
| Temperature | degrees Celsius or Kelvin |
| Mass | kilograms |
| Area | metres squared |
| Volume | metres cubed |
| Force, Weight | Newtons |
| Speed and Velocity | metres per second |
| Density | kilograms per metre cubed |
| Angle | degrees |
| Acceleration | metres per second per second |
| Moment | Newton Metres |
| Energy, Work Done | Joules |
| Electrical Charge | Coulombs |
| Electrical Current | Amps |
| Potential Difference | Volts |
| Resistance | Ohms |
| Radioactivity | Becquerels |
| Radiation Dose | Ohms |
| Frequency | Hertz |
| Magnetic Flux Density | Teslas |
| Moles | Mol |
| Concentration | Mol per decimeter cubed |
| Light intensity | Lux |