Metric system lab answer key

Earth Science Lab. Experiment Name: __________________________ PHSC 101. ________ Date: _____________ Experiment #1: On Physical Measurement 1. Title: Physical Measurement 2. Introduction Scientific measurement has gradually progressed to a high state of sensitivity; however, it is still difficult to make exact measurements because of the variability and uncertainty of manual and mechanical measuring devices. For example, a metric ruler calibrated in 1cm divisions has an uncertainty of (±) 0.5-cm; whereas a metric ruler calibrated in 0.1-cm subdivision and has an uncertainty of (±) 0.05-cm. The one with more subdivision has greater accuracy. The volume of a liquid can be measured with a graduated cylinder. A100 ml graduate cylinder marked in 10-ml interval has ten subdivisions, where each subdivision equals one milliliter. If one of the divisions is estimated, the volume has an uncertainty of (±) 0.5-ml. When reading a graduated cylinder read the bottom of the meniscus. Also observe the meniscus at eye level in order to avoid a reading error. The meniscus is the lensshaped surface. There are two major measurement systems of standard units in use today. These are the Metric and the English systems. The metric system is used throughout the world, except in the United States, where both systems are used. The objectives of this experiment are (1) to obtain measurements of mass, volume and length using the Metric System (SI Units) and the English Customary System (ECS); (2) to compare ratios of measurements obtained using both systems with standard values (3) to obtain proficiency in using analytical balance, metric ruler and graduated cylinder. 3. MATERIALS AND METHODS 3.1. Equipment (the following equipment will be used in conducting this experiment) a) Analytical balance e) Graduated cylinder b) Calibrated measuring plastic cups (8 fl. oz) f) Rulers (inches and centimeters) c) Wood blocks g) Metal rounds d) Small white plastic cups 1 3.2. Procedure ( instruction) 3.2.1. Volume Measurements Fill the small white plastic cup to the lid with water. Pour the volume of water in the cup into a 100-mL graduated cylinder and measure the volume to one decimal place by observing the bottom of the meniscus to half a subdivision (0.5ml). Record the volume in milliliters (ml) on the Data Table. Then pour the volume of water from the graduated cylinder into a calibrated plastic measuring cup with care and record the volume in fluid ounces (fl. oz.) on the Data Table. Replicate this volume measurement 3 times. Determine the volume ratio by dividing the volume in milliliters by the volume in fluid ounces. Determine the mean of the 3 ratios, which should be near the standard value, which is 29.6 ml/fl.oz Calculate the percent error of your measurement results using the following formula. % Error = */Standard value – observed mean/ x 100 Standard value *absolute difference (no negative sign) 3.2.2. Mass Measurements Measure the mass of three metal rounds in grams on the analytical balance, one at a time, and record the mass to the nearest hundredths of a gram on the Data Table. The balance should be reset to zero before each measurement. Switch the unit on the balance from gram to ounce (oz), measure and record the corresponding measurement under the column designated for ounce (oz.). Calculate the ratio of mass in gram to the mass in ounce for each metal round,