AP/H SCIENCE SKILLS: SPREADSHEETS & SIG FIG

1. AP/H SCIENCE SKILLS: SPREADSHEETS & SIG FIG Suggested summer work for incoming students

2. Why learn a spreadsheet? • Scientific inquiry generates data…and with the advent of computers, lots and lots of data. In turn, computer programs are used to compile and statistically analyze that data. Excel is a spreadsheet program used in academic and industry labs for organization, calculation, and presentation of data. • Excel is the spreadsheet program included in the Microsoft Office suite. There are free spreadsheet programs in Google Drive and LibreOffice.

3. Tech Requirements • This tutorial references a Mac running OS X (10.6.8) and MS Office (Excel) 2011 • If you use a PC, a different version of Office, Google Sheets, or LibreOfficesome details will be different than those of this tutorial • Look for command synonyms, different button locations, etc. • Search the web for a tutorial your specific hard/software if it is very different than this.

4. Build a Data Table • Copy a string of data from any source (MLB.com, bls.gov, ncdc.noaa.gov, etc) • Highlight a spreadsheet cell; paste the data in. If it all pastes into one cell, go up to the ‘data’ drop down menu and choose ‘text to columns’ to separate in cells.

5. • Repeat so you have a few sets of data in a table format • Title each row with an independent variable; each column with a dependent variable.

6. • Highlight all the cells; use the ‘borders’ button to add grid lines • Highlight the table; under ‘charts’ choose ’column’.

7. Graphed Data You can drag the graph around by the border

8. • Choose a chart layout and type in title, axes labels

9. Formulas for Calculations • Formulas start with the equal sign. Use math order of operations. • The SUM command is used to total a column or row. Write a formula, as above, or highlight the data to sum, and clickΣ.

10. Copying Formulas to Other Cells Put the cursor in the bottom right of the cell so that it changes to a +; hold and drag right to repeat the sum command in all the rows +

11. • Use the ‘decrease decimal’ button to round (see slides 16 – 20 to follow the rules for this).

12. As You Work Under View, check the ribbon and formula bar to make it easier to find tools/see your cell entries

13. Worksheet Displays Wrap text makes all your text visible Merge is useful for centering a title on your sheet, etc With Number you choose the format of your data

14. Try This • Insert additional rows and columns the number you highlight is the number that will be inserted • Graph only select columns of data from the table • Write and use other formulas i.e percent change = (((final – initial)/initial)*100) Use the formula builder button for a list of commands Completely flummoxed? Ask your parents – they may very well use Excel in their jobs.

15. Significant Figures • When reporting scientific data, ‘sig fig’ tell the reader the degree of accuracy of the measured data. • Measurements are accurate only to the intervals given on the scale. If the object falls between 2 points on a scale, any value between those two points is, at best, an estimate. • Example: The length of a pin is between 2.8cm and 2.9cm. You estimate it to be 2.85cm; your lab partner estimates it at 2.83cm. However, neither of you knows it’s length to the hundredth's place. Therefore, the first 2 digits are CERTAIN numbers of measurement & the 3rd is an UNCERTAIN number. Only CERTAIN numbers are reported; they are the ‘significant figures’.

16. Rules • Non-zero integers always count;1457 has 4 sig figs, 236 has 3 sig figs. • Zeros, three classes: • leading don't count; 0.0025 has 2 sig figs • captive count;1.008 has 4 sig figs • trailing only count with a decimal point; 100 has 1 sig fig,100.0 has 3 sig figs

17. Rounding off • If less than a 5 round down, if equal or greater than 5 round up. • In a series of calculations carry the extra digits through to the end then round off. • Round off to the correct number of sig figs: 4.348 to 2 sig figs is 4.3

18. Multiplication & Division: • The number of sig figs is the same as the measurement with the smallest number (this is a limiting number) • 4.56 x 1.4 = 6.384 = 6.4 3 sig figs 2 sig figs round to 2 sig figs • 8.315/298 = 0.0279027 = 0.0279 or 2.79 x10-2 4 s.f. 3 s.f. 3 sig figs

19. Addition & Subtraction: • The limiting number is the number with the smallest amount of decimal places. 12.11+ 18.0 + 1.013 = 31.123 = 31.1 the 18.0 is limiting as it only has 1 decimal place, so round off to 1 decimal place 0.6875 – 0.1 = 0.5875 = 0.6 the 0.1 is limiting so round off to 1 decimal place.

20. Practice • Do some calculations and practice rounding given sig fig. Check your work using this online calculator • Scientific methods • Metric units • Converting between units (dimensional analysis) • Exponential notation • Independent vs dependant variables Other Topics to Review