Scientific Measurement

1. Scientific Measurement • Length- the basic unit of length is the meter. • Meter- SI unit of length - It is the distance between the doorknob and the floor.

2. Scientific Measurement • Volume- is the amount of space that something occupies. • Liter - SI unit for volume....- A little more than a quart ... - Solid objects can have volumes in cubic centimeters

3. Scientific Measurement • Mass- is the amount of matter an object contains. • Kilogram- the basic SI unit for mass. • About 2.25 pounds. • A smaller unit is the gram.

4. The Metric System • Easier to use because it is a decimal system • Every conversion is by some power of 10. • Much easier to use when doing calculations.

5. The Metric System • A metric unit has two parts • A prefix and a base unit. • prefix tells you how many times to divide or multiply by 10.

6. SI Base Units • Length - meter - m • Mass - gram - g • Time - second - s • Temperature- Kelvin(K) or ºCelsius(ºC) • Volume - Liter - L

7. SI Prefixes • kilo k 1000 times • hecto h 100 times • deca D 10 times • kilometer - equals 1000 meters or about 0.6 miles

8. SI Prefixes • deci d 1/10 • centi c 1/100 • milli m 1/1000 • centimeter - 1/100 of a meter or less than half an inch

9. Measuring Length • Line up from zero not the end of the ruler • Small numbered divisions are centimeters (parts are mm) 0 1 2 3 4

10. Use a graduated cylinder. Hold it level with your eye. Read the bottom of the curve. Measures in millilitersmL. A meniscus is the curvature of the surface of the water Measuring Volume 30 20 10

11. Mass vs Weight • Weight is a measure of the pull of gravity and, mass is the amount of matter. • The weight of an object canchange, but an object’s mass is constant.

12. Triple Beam Balance Use • Use a triple beam balance • First zero the balance. • Then place object on pan. • Then move largest weight first, until pointer tips to right and move back one notch.

13. Triple Beam Balance Use • Move next smallest weight, until pointer tips to right and move back one notch. • Move smallest weight, until pointer is at mid-position. • When balanced, add up the weights.

14. 0 10 20 30 40 50 60 70 80 90 100 0 100 200 300 400 500 Triple Beam Balance 0 1 2 3 4 5 6 7 8 9 10

15. Electronic Balance Use • Press on button to turn on. • If balance in not on zero, press zero button. • Place object on pan and, record mass in grams. • Turn balance off at end of lab period.

16. Date :01/19/11Instructional Objective:1.Review the metric system2.Learn how to convert the metric system Review Questions:a.) 68.882 kg = _______________________cgb.) 428 mm = ________________________dkmOther InstructionsMove to the lab station and Work on your Density lab.Homework:Do the SI unit work sheet.

17. m k h D d c m L g Metric Conversions • how far you have to move on this chart, tells you how far, and which direction to move the decimal place.

18. m k h D d c m L g Metric Conversions • Change 5.6 mg to kilograms. • starts at milli position and move six places to the left.

19. m k h D d c m L g Metric Conversions • move the decimal point six places to the left 0.0000056 • 5.6 mg = 0.0000056 kg

20. m k h D d c m L g Metric Conversions • Change 5.6 m to millimeters • starts at the base unit position and move three places to the right.

21. m k h D d c m L g Metric Conversions • move the decimal point three to the right 5600. • 5.5 m = 5600. mm

22. m k h D d c m L g Metric Conversions • convert 25 mg to grams • convert 0.45 km to mm • convert 35 mL to liters

23. Scientific Measurement • Density- tells you how much matter is packed into a given volume. • Calculated by dividing mass by volume ( D = M ) . V

24. Density Problem • Calculate the density of an object with a mass of 25 g & a volume of 5.0 mL. • .D = M = 25 g = 5.0 g/mL . V 5.0mL

25. Example problems 10 km = _____ dm 0.1 hm = _____ m 1cm = _____ hm 0.01 m = _____ mm 100 dg = _____ dag 10 hg = _____ kg 0.1 mg = _____ dg 0.001 cg = _____ mg 1 kg = _____ g 0.01 dag = _____ cg Now let’s see how well you can perform some conversions!!

26. The centigrade (Celsius) scale • temperature (K) = temperature (°C) + 273.15 • the melting point of water is = 0°C = 273.15 K • the boiling point of water is = 100°C = 373.15 K

27. reading a graduated cylinder

28. The boiling point *is the temperature at which the vapor pressure of a liquid is one atmosphere. *Units - K (Kelvin)

29. The Fahrenheit scale • the melting point of water = 32°F • the boiling point = 212°F.

30. The SI unit of temperature is Kelvin (K). Notice that there is no degree sign used with the abbreviation. To covert from Celsius to Kelvin temperatures: C--> K + 273 K--> C - 273 Celsius Kelvin Fahrenheit Freezing: 0 273 32 Boiling: 100 373 212

31. Dervied units: are combinations of SI units. Volume: amount of space occupied by an object. Volume=Length X Width X Height V= l X w X h This is used to calculate the volume of a cube and combines three length measurements together. Density: the mass per unit volume of a material. Density=Mass/Volume D=m/V This is a combination of units of mass and volume.

32. Density of the regular object Mass- find the mass of the object using a balance Volume- To find the volume by measuring the length, width, and height. Then calculate density=mass/volume

33. Density of the irregular object Mass- find the mass of the unknown using a balance Volume- To find the volume, first measure the water that can immerse the irregular object in a graduated Cylinder. Then dropped the object in the cylinder and note the displacement measurement. Density = mass/volume.