rs Analyzing Data and "

Transcription

1 rs Analyzing Data and " I Communicating Results Kt!f Tenff/ communication: sharing information Analyzing Data When you organize information, you put it in a logical order. In scientific experiments, it is important to organize your data. Data collected during an experiment are not very useful unless they are organized and easy to read. It is also important to organize your data if you plan to share the results of your experiment. Scientists often organize information visually by using data tables, charts, graphs, and diagrams. By using tables, charts, graphs, and diagrams, scientists can display a lot of information in a small space. They also make it easier to compare and interpret data. Tables are made up of rows and columns. Columns run up and down. Rows run from left to right. Tables display data in an orderly arrangement, often numerically. For example, reading a table containing the uses of sulfuric acid shows that the largest use of sulfuric acid is in fertilizers. Figure 15 is a table that shows some uses of sulfuric acid. - USES OF SULFURIC ACID Product f--. Percentage Dyes, batteries, paint, explosives 15 Raw materials 115 r--" Fertilizers _.. 60 Petroleum refining Metal processing 5 A Figure 15 Graphs, such as bar graphs, line graphs, and circle graphs, often use special coloring, shading, or patterns to represent information. Keys indicate what the special markings represent. Line graphs have horizontal (x) and vertical (y) axes to indicate such things as time and quantities. ~ EXPLAIN: How do tables and graphs help you analyze data? js Sharing Results When you talk to a friend, you are communicating, or sharing information. If you wri~e ~ letter. or a.report, you a~e ~("" commurucating but ill a different way. SClen~ communicate all the time. They communicate to share results, information, and opinions. They write books and magazine or newspaper articles. They may also create Web sites about their work. This is called written communication. Graphs are a visual way to communicate. The circle graph in Figure 16 is showing the same information that is shown in Figure 15. The circle graph presents the Petroleum refining 5% Metal processing 5% Raw materials 15% Dyes, batteries, paint, explosive 15% information in..figure 16 Circle graphs are a good a different way. way to show parts of a whole. ~ LIST: What are some ways to communicate the results of an experiment? [6-Making Key Tern«infer: to form a conclusion Predictions predict: to state ahead of time what you think is going to happen ~" \ ) Thinking of Possibilities When you infer something, you form a conclusion. This is called making an inference. Yourconclusion will usually be based on observations or past experience. You may use logic to form your statement. Your statement might be supported by evidence and perhaps can be tested by an experiment. An inference is not a fact. It is only one possible explanation. When you predict, you state ahead of time what you think will happen. Predictions about future events are based on inferences, evidence, or pq.st experience. The two science process skill(. inferring and predicting are very closely related': ~ CONTRAST: What is the difference between inferring and predicting? ) 0 /' R

2 Scientists working with very lqw temperatures use the Kelvin scale. The Kelvin scale is part of the 5I measurement system. It begins at absolute zero, or OK.This number indicates, in theory at least, a total ck of heat. _. _.. "_.' CoMPARING -:~ ;._~.,...;... TEMPEMrURESc:A.LES.... ~_;",...,;._.,_. _"; w_.. _ _. _. _. _-'-,-:" r''''-'''''' ''-'---' _.._-...- _._ , Kelvin : Fahrenheit i Celsius I_~;~~e.r:~:~.., t.~_~~! Human body : 310K 98.6 F. 3JOC j_..:.:~..._..".j ~,~~~ L::_rn~:~~~r:: ' ' Freezingpoint 273K 132 F i O C of water I : I 't' ~ ~ ~~ ~----~--,..._."_---I_~ Absolute zero! OK F C Figure 13 of C 100 H~-l?~ ~ctutity ;~~ READING A THERMOMETER You will need safety goggles, lab apron 2 beakers, a heat source, ice water, a wax pencil, a ruler, and a standard Celsiusthermometer. 1. Boil some water in a beaker. '&CAUTION: Be very careful when working with heat. Place your thermometer in the beaker. Do not let the thermometer touch the sides or bottom of the beaker. Wait until the mercury rises as far as it will go. Record the temperature. 2. Fill a beaker with ice water. Place the unmarked thermometer into this beaker. Wait until the mercury goes as low as it will go. Record the temperature ,~~ 70.~., STEP 1 Record the temperature the boiling water. of Practicing Your Skills 3. IDENTIFY:What is the temperature at which the mercury would go? rose as high as it 4. IDENTIFY:What is the temperature at which the mercury went as low as it would go? figure 14 The Fahrenheit and Celsius scales ~-,~ -":Ilk" -., ~ NAME: What are the three scales used to measure temperature? }I

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4 Introduction to the METRIC SYSTEM Length, mass (or weight), and temperature can be measured using several different types.of units. The two measurement systems generally in use are the English System and the Metric System. The English System uses the foot, the pound, and the Fahrenheit (OF) scale. The Metric System uses the meter, the kilogram, and the Celsius (OC) scale. Most of us grew up using the English System, so why change? Metrification is important because nearly all world trade involves metric goods. Presently, the US is out of step with the rest of the world. This compromises our international competitiveness and limits markets for American-rnade products. There are only two other countries in the world (as of 1990) that do not use mebie measurements, Any guesses which ones? No. not England. not France, not Canada, not Mexico. If you guessed any countries other than Liberia and South Yemen, you woukt be wrong. Surprised? All of us are already familiar with at least some metric measurements: 2 liter soda bottles, 35 millimeter film, 10K (kilometer) fun runs, etc. Can you think of any others? Many cars are already buihwith speedometers in both miles per hour and kilometers per hour. And many products are sold with their weight in both ounces and grams. For temperature, the Fahrenheit scale has an seemingly arbitrary basis in which water freezes at 32 F and boils at 212 F. With the Celsius scale, things are much easier to remember. Water freezes at O C and boils at 100 C. More useful, room temperature is approximately 72 F or 23 C, and a hot day is about 100 F or 37 C. [Another temperature scale is sometimes used in science, the Kelvin scale, in which freezing and boiling of water are also separated by 100 degrees. but at 273 K and 373 K. This scale is sometimes called the absolute scale because it is based on absolute zero, the temperature at which molecular motions cease. Absolute zero = 0 K = -273 C = -459 F. The degree sign is not used with K because the temperature units are called Kelvins, not degrees Kelvin.] Learning to use the Metric System should not be difficuh for us. Remember that even illiterate street vendors in other countries use and understand the metric system. It is really a lot easier than the (3

5 English System because everything works on groups of ten (instead of 12 inches to a foot, 3 feet to a yard, 5280 feet to a mile). Equivalencies: 10 millimeters = 1 centimeter 100 centimeters = 1 meter 1000 meters = 1 kilometer The prefixes are useful: mega = a million times kilo = a thousand times hecla = a hundred times (not frequently used) deca = ten times (not frequently used) deci = one tenth (1/10) (not frequently used) centi = a hundredth (1/100) milli = a thousandth (1/1000) micro = a millionth (1/1,000,000) Using the prefixes, we can recognize that there are 1000 millimeters in a meter, 100 centimeters in a meter, 10 decimeters in a meter, and 1000 meters in a kilometer. The abbreviations for the various units are written in lower case letters (not capitals), and can be found in the appendix to your book. Just about the only thing you have to learn is approximately how large the various units are, so that you have some frame of reference. Comparisons: 1 gram is about the weight of a paperclip or a raisin. 1 kilogram is a little more than 2 pounds. 1 liter is a little more than a quart 1 kilometer is a little more than half a mile. 1 meter is a little more than a yard. 1 centimeter is a little less than half an inch. 1 millimeter is about the size of the ball in a ball point pen, or the width of a pencil point Exact conversions between units are listed in the Appendix to your textbook. There is no real need to memorize them as long as you understand how big the metric units are, and as long as you are able to make a conversion, should the need arise. Many rulers are sold with measurements in both systems. (

6 METRICS AND MEASUREMENT Name _ 3clentists use the metric system of measurement. based on the number 10. It Is important o be able to convert from one unit to another. kilo hecto deca Basic Unit deci centi mini (k) (h) (da) gram (g) (d) (c) (m) liter (L) () meter (m) 10-1, ,, Using the above chart I we can determine how many places to move the decimal point and in what direction by counting the places from one unit to the other. Example: Convert 5 ml to L. Answer: To go from milll (m) to the basic unit, liters, count on the above chart three places to the left. Move the decimal point three places to the left and 5 ml becomes L Convert the following. l. 35mL = dl 6. 4,500mg = g = kg cm = mm mm = em kg = dag 4. l,ocxjl ~ kl, 9. O.075m = cm 5. ',OOOmL = L g = mg.. 15

7 WtEA.SURING LENGTH Name _~ _ Whot.lengths ore marked on the following centimeter ruler? em mm a) b) c) J) e) Measure the following lines with a centimeter ruler. f) g) h) I) j) k) l) ~~-- I.

8 Observation and Measurement of the Environment - 10 E. Mass InstTument- _ Riders., 0,' 'r,.. 2. Units: (a.) _ (b.) _ Base 3. Determine. the mass by reading the scales of the beams in the illustrations below: ~ -y--- -Y- I if J 00 \ (a.),_---- (b.) (c.) _

9 Reading a Trlple Beam Balance Name _--_-- _ ( TO-determine the mass--orwelgfit of an object -usin-g-0triple beam bala-nee-i find the sum of the masses shown on all the riders. Find the massindicated on each of the triple beam balances pictured below. o o, _ o o o o 1 ' Earth Science IF Instructional Fair. Inc.

10 I...~.-..~ ~-,, _._ _ _._.._- - _-_._.._.. -_.- _-' - F. Weight - ---'-.---.;.. _ 1.In~ument-_ _ otservanon and Measurement of the Environment - 11/ 2. Units: (a.) Metric = (b.) Eng!ish -.,..,.-.._----,,---,.,-,- ~ 'n ~r - " - -t: I 1= '.~ ',. ', If' -= 3. Factors that cause weight or effect weight: (a.) The amount of the object possesses. Wooden popsicle Stick / ----.; Wooden Ruler \ ~. (b.) The amount of n acting on the object. C)... g2j Wooden.. Ruler 1m.--.:«:~. ".' ~'r---~-- -:. :. '/ "~.: '.. :. "...-.; '~~.. '. r.t", ':... "':~,:~~.;.. ",.~~.. ~. ~McioN : ':.'.' "':..:, I L D. J. Mills!999