Alexis Grant Lab 1

Alexis Grant 09/27/23 Professor Ryan BSC2010C Some of the most important skills a science student can develop include taking valid measurements and learning how to record and interpret data. After completing this lab, you will be able to make conversions within the metric system, create and interpret data or graphs, identify dependent and independent variables in an experiment, and know the proper procedure for conducting a scientific investigation. Part 1: The Metric System of Measurement The metric system is a system of measurement based on powers of ten. The metric system is used worldwide except for the United States, Liberia and Myanmar. Three “base units” in the metric system are: Meter (m) = Metric unit for measuring length / distance Liter (L) = Metric unit for measuring volume Gram (g) = Metric unit for measuring mass Each of these base units may be used alone or in conjunction with a prefix: Prefix Meaning Relation to Base Unit milli- (mm) Thousandth 10 -3 (0.001) centi- (c) Hundredth 10 -2 (0.01) deci- (d) Tenth 10 -1 (0.1) none Base unit (meter, Liter, 1

gram) deka- (da or dk) Ten 10 1 (10) hecta- (h) Hundred 10 2 (100) kilo- (k) Thousand 10 3 (1000) Note that the meter base unit and the milli- prefix both use a lowercase “m” as a symbol. If you were given a measurement such as 545 m, this would be read as “five hundred forty five meters.” Milli- can only be used in conjunction with a base unit, such as 290 mm, which would be read as “two hundred ninety millimeters.” To do metric calculations, you divide or multiply by powers of ten. Multiply when converting from a large unit to a smaller one; divide when converting from a small unit to a larger one. It may be easiest to set these up as a multiplication problem that allows you to cancel units. Example: Convert 87.3 milligrams (mg) to kilograms (kg). 87.3 milligrams x 1 gram x 1 kilogram = 0.0000873 or 8.78 x 10 -5 1000 mg 1000 grams Exercise 1: Metric conversions 1,938 kg = 19380000 cg 0.32 cL = ________ L 5,809 m = _____ cm 0.09 mg = ________ cg 13 mm = ____ km 4,443 cm = _______ m 88 cm = ____ km 3,172 g = _____ mg 0.79 L = _____ dkL 5 dm = _______ hm Part 2: Scientific Method

The process of scientific investigation employs a series of steps to acquire new knowledge. While the names and order of the steps may vary from author to author, experimental science is based on gathering observable, measurable evidence through the testing of a hypothesis. The experimental approach generally assumes the following format:  First, an observation is made followed by a specific question regarding the organism or system being studied.  Then, a hypothesis is developed as a tentative answer to the question or explanation based on the available information at the time. For example...”high exposure to UV light causes skin cancer.” If no information is available, the hypothesis is often little more than your best educated guess. To help with designing an experimental procedure to test your hypothesis, a prediction is made. This is typically written as an “if…then….” Statement: “If skin cancer is related to ultraviolet light, then people with a high exposure to UV light will have a higher frequency of skin cancer.”  Next, an experimental procedure is devised. This consists of the procedural steps you intend to use to test the validity of the hypothesis, as well as the materials necessary to do so.  The process of running the procedure will provide some experimental results, called data. Data can be presented in a clear, meaningful way with a graph, table, or chart. From your experimental results, some conclusions may be drawn. These should either support or reject your stated hypothesis, providing at least a partial answer to the question that initiated the investigative process. The conclusion(s) from a single experimental procedure can never absolutely prove a hypothesis; experimental replications are necessary. This is the principal reason why conclusions in science must remain tentative and are subject to being modified as additional information becomes available.