# 111.02Density & Measurements Experiment 2.docx -...

• No School
• AA 1
• 10

This preview shows page 1 - 3 out of 10 pages.

Experiment #2. Density and Measurements (n) Goals 1. To measure and record length, volume and mass accurately with the correct number of significant figures 2. To use significant figures correctly in calculations. Making Measurements Measurements are central to science and medicine. Scientists and medical professionals need to read and report measurements accurately and precisely to convey information to others. In this lab you will to learn how to read scientific instruments and report the results with the correct number of significant figures. Measurements contain certain and uncertain digits. The final digit of a measurement is assumed to have uncertainty and is usually estimated from the instrument being read. You will be expected to carefully and correctly record measurements using the procedures below for rest of the course. Units of Length We will use rulers to measure length. The standard unit of length in the metric system is the meter (m). A meter is divided into 100 centimeters (cm). Each centimeter is divided into 10 millimeters (mm). Measurements taken with instruments with a scale, such as rulers, should be recorded to the nearest 1/10 of the smallest division. Two examples are below. Smallest division on the ruler: 0.1 cm 1/10 of smallest division: 0.01 cm Measurement should be read to the nearest: 0.01 cm The object lies between the 7.2 and 7.3 cm lines. The space between the lines should be mentally divided into 10 to estimate the last digit of the measurement. A correct reading of this instrument could be 7.24 cm . Units of Volume Volume is a derived unit based on length. The unit of basic metric unit of volume is the liter (L). 1 liter is equal to 1 cubic decimeter (dm) 3 . There are 1000 mL in 1 L. A milliliter is the same volume as 1 cm 3 . 1 liter = (1dm) 3 = (10 cm) 3 = 1000 cm 3 = 1000 mL We will use several types of instruments to measure volume in chemistry class. Beakers glass containers with straight sides used to hold, mix and heat liquids markings give an approximate volume beakers are not used for careful volume measurements
Erlenmeyer Flasks glass containers with tapered sides and a narrow opening. the shape is useful for swirling liquids without spilling and for limiting evaporation markings give an approximate volume Erlenmeyer flasks are not used for careful volume measurements Graduated Cylinders long narrow cylinders with volume markings (also known as graduations) used to accurately measure volume some have a plastic guard to prevent breaks – it should be at the top of the cylinder. graduated cylinders are not used to heat liquids – the shape of the base does not transfer heat well graduated cylinders are never used to mix substances or hold solids – solids get stuck at the bottom of the cylinder and are difficult to mix and clean.

#### You've reached the end of your free preview.

Want to read all 10 pages?

• Fall '19

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern