# Lab 2: Microscopy and the Metric System

Topics: Lens, Lenses, Eyepiece Pages: 10 (2331 words) Published: March 24, 2013
Microscopy and the Metric System

Margaret E. Vorndam, M.S. Version 42-0090-00-01

Lab Report Assistant
This document is not meant to be a substitute for a formal laboratory report. The Lab Report Assistant is simply a summary of the experiment’s questions, diagrams if needed, and data tables that should be addressed in a formal lab report. The intent is to facilitate students’ writing of lab reports by providing this information in an editable file which can be sent to an instructor.

Exercise 1: Measuring Length, Weight, Volume, and
Temperature

Try the following conversions for practice.

240,000 ng =0.24mg =0.00024g50 cm =500 mm =0.5m

Procedure

1. Length: A metric ruler is useful for measuring items of length. The ruler below measures in mm, indicated by the small mm near 0.

a. How many mm are there in 1 cm?10, in a meter (m)?1000

(Ruler is not to scale. See ruler in dissection kit.)

b. Locate a measurable object to use for this exercise. If the object is long, obtain a yardstick that includes a cm scale; they can be found in local hardware stores.

c. Record the length of the object below and do the conversions:

Name of object: ID card
8.5 cm=85mm=0.085m

Volume: Always pour an approximate volume of liquid into a clean beaker and then from the beaker into the volumetric flask or graduated cylinder. This will minimize contamination of the parent liquid source. Dispose properly of any leftover liquid. Do NOT pour it back into the original container. Why? This is so the original liquid does not get contaminated.

When using a pipet or dropper to measure liquid, pour an aliquot into a clean beaker and then draw up the liquid from the beaker into the pipet. NEVER try to draw up chemicals by mouth. Why? Chemicals could go into your mouth, which is potentially dangerous and should never be done no matter if they deemed “safe” or not.

Weight: Use the pen scale from the lab kit to measure out exactly three grams of sugar. Make sure to tare the bag before adding the sugar. Why must the bag be tared before adding the sugar? This is done so the weight of the bag is not counted with the weight of the sugar. You must think about the weight of the bag when weighing out the three grams of sugar.

How is the weight of the bag accounted for when the sugar is weighed? The bag is weighed first and then the 3 g of sugar is added on top of that weight so at the end the weight is more than 3g total due to the bag.

Temperature:

Practice converting the following with this conversion formula:

45°F = 7.2 °C 62°F =16.7 °C 98.6°F =37°C

Use a Celsius thermometer to measure the °C temperature of several different aliquots of cold and warm tap water. Make sure to allow the thermometer to remain until the temperature is stable and no longer changes. Record the temperatures:

Cold-15°C

Warm - 29°C Hot- 48°C

Questions

A. What laboratory equipment would be used to measure the following items?

5 g flour| Beaker and scale| 36 mL water| Graduated cylinder| The length of a frog’s leg| ruler| 36 g water| Beaker/balance| 38ºC| thermometer| Volume of a turtle*| Water displacement| 125ºF| thermometer| Volume of blood| Graduated cylinder| Weight of a plant| Bag and scale| Weight of blood| Beaker and scale| Temperature of a fish’s body| thermometer| Temperature of blood| thermometer| *This answer may require some creativity. How could it be done?

B. Provide the calculation steps, including the conversion factor that would be needed to convert the following measurements, and the final answers. Use U.S. and liquid units where appropriate.

248 g| = 248,000 mg| 145,000 μL| = 145mL|
536 mL| = 536 cc| 0.372 kg| = 372 g|
0.75 L| = 750,000 μL| 20.39 cm| = .2039 m|...