# Density and error Density Density Compares mass amount

- Slides: 12

Density and % error

Density • Density – Compares mass (amount of • matter) of object to its volume (amount of space occupied) mass per unit volume (g/cm 3) M D= V M D V

Density • Mass is always in g • Volume is always in cm 3 • If not… you must convert • Note: • I L = 1 dm 3 • 1 m. L = 1 cm 3 g/ cm 3 Is considered to be a derived unit because it combines 2 SI units

Example • Calculate the density of an object that has a volume of 4. 67 cm 3, and a mass of 56. 9 g • D=m V • D= x • M= 56. 9 g • V= 4. 67 cm 3

Examples • X = 56. 9 g 4. 67 cm 3 • x=12. 2 g/cm 3 • * RULE FOR SIGNIFICANT DIGITS WHEN MULTIPLYINMG OR DIVIDING APPLY HERE

Density • An object has a volume of 825 cm 3 and a density of 13. 6 g/cm 3. Find its mass. GIVEN: WORK: V = 825 cm 3 D = 13. 6 g/cm 3 M=? M = DV M D V

Density A liquid has a density of 0. 87 g/m. L. What volume is occupied by 25 g of the liquid? GIVEN: WORK: D = 0. 87 g/m. L V=? M = 25 g V=M D V

Density You have a sample with a mass of 620 g & a volume of 753 cm 3. Find density. GIVEN: WORK: M = 620 g V = 753 cm 3 D=? M D V D=M V

Ways to determine density 1. Regularly shaped objects – direct volume measurement (l x w x h) 2. Irregularly shaped objects- use water displacement method (graduated cylinder) to find volume. Note: mass is found the same way regardless the shape of the object

Density • I have a block that measures 5. 25 cm by • • 2. 25 cm by 8. 50 cm. I weigh the block and find its mass to be 5. 85 g Calculate the density of the block in g/cm 3

For example • A chunk of metal has a mass of 5. 25 g. It is placed in a graduated cylinder containing 25. 0 ml of water. Once the metal is placed in the graduated cylinder, the water rises to 38. 2 ml. What is the density of the metal?

% error • % error – the deviation from the accepted value during an experiment. Usually caused by human error. % error = (your value - literature value) x 100 • • literature value • It is always a positive number Page 38 in textbook has a list of densities

- Density water
- Type 1 or type 2 error statistics
- Parallax error
- Difference between round-off error and truncation error
- Crc example
- Absolute error
- Type 1 error vs type 2 error example
- Gyro theory
- What is a hypothesis
- Alternating series error bound
- Error sistematico
- Error sistematico
- Error sistematico y error aleatorio