STUDY GUIDE: SCIENTIFIC NOTATION

Many labs (but not all of them) will involve measuring, calculating or determining a particular value. Sometimes (but not always), that value can be compared to a "known" or "actual value". The best way to do that is by calculating the percent (%) error between the value you determined in your lab, and the "known" value.

Calculate your percent error in the body of your conclusion. To calculate error percent:

Take the difference between the value that you determined in your lab and the "known value" (subtract one from the other). Don't worry if you get a negative number -- we are after the difference between the values (in math we call that the "absolute value")

Multiply the decimal value that you calculated above by 100 to get a more easily readable % value.

FOR EXAMPLE:

Let's say you are doing a lab to determine the boiling point of water. After bringing a beaker of water to boil, you take several temperature readings and the results were:

Trial #1: 99.5 degrees Celsius

Trial #2: 99.8 degrees Celsius

Trial #3: 100.5 degrees celsius.

Using step #1 (above) you calculate the averages of those three trials: 99.9 degrees celsius.

We know from the textbook, however, that water actually boils at 100 degrees celsius (at sea level, but we'll discuss that at a later time). To calculate the percent error: