USING GRAPHING SKILLS

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1 Name: BOLOGY: Date: _ Class: USNG GRAPHNG SKLLS NTRODUCTON: Recorded data can be plotted on a graph. A graph s a pctoral representaton of nformaton recorded n a data table. t s used to show a relatonshp between two or more dfferent factors. Two common types of graphs are lne graphs and bar graphs. n ths nvestgaton, you wll nterpret and construct a lne graph and a bar graph. LNE GRAPHS: n laboratory experments, you wll usually be controllng one varable and seeng how t affects another varable. Lne graphs can show these relatons clearly. For example, you_mghl.perform an experment n whch you measure the growth of a plant over tme to determne the rate of the plant's growth. n ths experment, you are controllng the tme ntervals at whch the plant heght s measured. Therefore, tme s called the ndependent varable. The heght of the plant s the dependent varable. Table gves some sample data for an experment to measure the rate of plant growth. The ndependent varable s plotted on the x-axs. Ths axs wll be labeled Tme (days), and wll have a range from 0 days to 35 days. Be sure to properly label your axs ncludng the unts on the values. The dependent varable s plotted on the >>-axs. Ths axs wll be labeled Plant Heght (cm) and wll have a range from 0 cm to 5 cm. Thnk of your graph as a grd wth lnes runnng horzontally from the y- axs, and vertcally from the x-axs. To plot a pont, fnd the x (n ths example tme) value on the x axs. Follow the vertcal lne from the x axs untl t ntersects the horzontal lne from the^-axs at the correspondng >> (n ths case heght) value. At the ntersecton of these two lnes, place your pont. Fgure shows what a lne graph of the data n Table mght look lke. Table Expermental Data for Plant Growth versus Tme -Tme <days)^mat heght (cm}^

2 BAR GRAPHS: Bar graphs make t easy to compare data quckly. We can see from Fgure 4 that Jupter has the largest radus, and that Pluto has the smallest radus. We can also quckly arrange the planets n order of sze. Bar graphs can also be used to dentfy trends, especally trends among dfferng quanttes. Examne Fgure 5 below. Fgure 4 Rad of the Planets Fgure 5 Tme Spent on Producton Work 3 The data are represented accurately, but t s not easy to draw conclusons quckly. Remember that when you are creatng a graph, you want the graph to be as clear as possble. f we graph the exact same data on a graph wth slghtly dfferent axes, as shown n Fgure 6, t may be much easer to draw conclusons. Fgure 6 0 Tme Spent on Producton Work m

3 ATM: To correctly nterpret and construct a lne graph and a bar graph. PRE-LAB DSCUSSON: Read the entre nvestgaton. Then answer the followng questons.. Would a lne graph or a bar graph be better for showng the number of brds of each color n a populaton?(l) Explan why?() 2. How could you plot more than one respondng varable on a lne graph?( ) 3. Where do you place the manpulated varable on a lne graph?(l) 4. Whch type of graph would you use to show comparsons?(l) Explan the reason for your answer.(l) 5. Why s t mportant to have all parts of a graph clearly labeled and drawn?(l) PROCEDURE: Part A. nterpretng Graphs:. The type of graph that best shows the relatonshp between two varables s the lne graph. A lne graph has one or more lnes connectng a seres of ponts. See Fgure. Along the horzontal axs, or x-axs, you wll fnd the manpulated varable n the experment. Along the vertcal axs or^-axs, you wll fnd the respondng varable. Lne Graph /s / Numercal scale fgure /

4 f.how long dd t take for plant to grow 6 cm? 2. Use the lne graph n Fgure 2 below to answer questons a through f below. (6) 2 < SrowdofPla ts 0 n a s 4 /.> '. ' ' ^^ -"' ^ 0< 7 / ''/ /.' J Plant Plant 2 Plant 3 Tme (Days) Fgure 2 3. A bar graph s another way of showng relatonshps between varables. A bar graph also contans an x-axs and a ^-axs. But nstead of ponts, a bar graph uses a seres of columns to dsplay,. data. See Fgure 3. On some bar graphs, the ^-axs has labels rather than a numercal scale. Ths type of bar graph s used only to show comparsons. Fgaro 3

5 Red Blood Cell Count Durng Human Growth? ? f ^l ^s? S^ t s 4; *! ^! Brth? 4 b 8* to? -cp;? 4 8 >o. 2 -t" 4+ (M)( 4+ Months Years Tlma Fgure 4 4. Use the bar graph n Fgure 4 (above) to answer questons a through e below. (5) a.at brth, what s the average number of red blood cells per mm3 of blood? b.what appears to happen to the number of red blood cells between brth and 2 months? c What happens to the number of red blood cells between the ages of 6 and 8 years? d.between what ages s a human lkely to have 4.6 mllon red blood cells? e.after 4 years of age, do males or females have a hgher red blood cell count? Part B. Constructng Graphs:. When plottng data on a graph, you must decde whch varable to place along the jc-axs and whch varable to place along the v-axs. Label the axes of your graph accordngly. Then you must decde on the scale of each axs; that s, how much each unt along the axs represents. Scales should be chosen to make the graph as large as possble wthn the lmts of the paper and stll nclude the largest tem of data. f the scale unt s too large, your graph wll be cramped nto a small area and wll be hard to read and nterpret. f the scale unt s too small, the graph wll run off the paper. Scale unts should also be selected for ease of locatng ponts on the graph. Multples of or 0 are easest to work wth.

6 L[ l _ 2. Use the nformaton recorded n Data Table to construct a lne graph on the grd provded below. You should label each axs, mark an approprate scale on each axs, plot the data, connect the ponts, and gve your graph a ttle. (0) Use 2 small squares = C Use small square = breath per mnute. DATA TABLE : Breathng rate of freshwater Sunfsh. Temperature (C) Breathng rate (per mnute) " ^ ~ t" " t " " X t! ; _ : : : z _ ~ t _: _n _ t t z. c L

7 _: ::: :x ^_ X^ l _ 4: ' _ 3. Use the nformaton recorded n Data Table 2 to construct a bar graph on the grd provded below. You should label each axs, mark an approprate scale on each axs, plot the data, darken/color the columns of the graph, and gve your graph a ttle. (0) (Use 5 small squares = lmonth: 2 small squares = lml.) Data Table 2 Month Jan. Fell. Mar Aprl May June July Aug. Sept. Oct Nw. Dec. Ranfall ml D Average Ranfall n Wllamette Valley z ; t _ ^ x Z ~ - ~X" _ ~ X - - ' \ \! r:_ t^_ t x _,_ [ ^ ; j! j j! J _^ ^j_ ^ _

8 ANALYSS AND CONCLUSONS:. Comparng and Contrastng: How s a graph smlar to a data table?(2) 2. Comparng and Contrastng: How s a lne graph dfferent from a bar graph?(2) 3. Usng Graphs: Does a steep curve on a lne graph ndcate a rapd or slow rate of change?(l) 4. Usng Graphs: You are conductng an experment to measure the gan n mass of a young mouse over a ten-week perod. n constructng a graph to represent your data, whch varable should you place along the ^-axs and whch varable should you place along the^-axs? (2).y-axs Explan your answer. (4) 5. Usng Graphs: What s an advantage of usng multple lnes n a lne graph? (See Fgure 2.) ()