1. SI UNITS

2. DO NOW Work silently and independently to answer the following questions Which units would you use to measure the following items? Ex: The weight of a person. Answer: Pounds or Kilograms The temperature outside A roadtrip across the country A track and field event Weightlifting A bottle of soda The length of a school day The length of a school year Why do you think units are important to a scientist. Give 2 reasons.

3. Objective SWBAT identify the base SI units and apply the appropriate prefixes on an exit ticket.

4. What is a Unit? UNIT: An individual thing or person that is single or complete, esp. for purposes of counting or for calculation. Examples: A family is a unit! A piece of candy is a unit! A piece of pizza! A pound! A homerun! One of your own?

5. Guided Notes: SI Units What is SI? The System International. A system of units based on the metric system. The system is standardized meaning that scientists all over the world are using the same units. THOUGHT QUESTION: Why do you think this is important for scientists?

6. Base Units The SI system uses 7 base units Base unit: a defined unit in a system of measurement that is based on an object or event in the physical world MeasurementBase Unit TimeSecond (s) LengthMeter (m) MassKilogram (kg) TemperatureKelvin (K) Amount of a substanceMole (mol) Electric currentAmpere (A) Luminous (light) intensityCandela (cd)

7. What is Kelvin? Kelvin is a measure of temperature developed by Lord Kelvin, a Scottish physicist. The equation for Kelvin involves adding 273 degrees to the temperature in Celsius. K=C+273 Example: Water freezes at 0 degrees Celsius. That is 273 degrees in Kelvin 0 + 273= 273 K 273 is the magic number

8. SI Prefixes If the base unit for distance in SI is the meter, what is a kilometer? SI uses a system of prefixes to describe the magnitude of measurements. These prefixes are based on powers of 10. 1 kilometer=1000 meters Kilo=1000 x base unit

9. Prefixes

10. Derived Units Derived Units: A unit that is defined by a combination of base units. Example: Density=Mass/Volume The density of water is 1 g/mL

11. Practice: Base Units MeasurementBase Unit Time Meter (m) Mass Temperature Amount of a substanceMole (mol) Amperes (A) Light IntensityCandela (cd)

12. Practice: Celsius to Kelvin Conversion Convert to Kelvin 25 degrees Celsius -10 degrees Celsius Convert to Celsius 394 degrees Kelvin

13. Independent Practice Work silently and independently. Use your notes.

14. Pop Quiz Write out the following numbers in scientific notation:.75 0.0000000033939 Write out the following number in standard notation: 7.39 * 10 8