1. Identify four base units of measurement; identify and use prefixes kilo- through milli- .
2. Record measurements and perform calculations using scientific notation.
Scientific study is conducted using System International or SI units -- also known as the metric system. Students have used this system over the years so it's not unfamiliar, but they have been on summer vacation and not really using it. Americans never really got rid of the English system of measurement (pounds, ounces, inches and Fahrenheit degrees), so a reminder is useful to students.
Noun1. SI system - a complete metric system of units of measurement for scientists; fundamental quantities are length (meter) and mass (kilogram) and time (second) and electric current (ampere) and temperature (kelvin) and amount of matter (mole) and luminous intensity (candela); "Today the United States is the only country in the world not totally committed to the Systeme International d'Unites"International System, International System of Units, SI unit, Systeme International, Systeme International d'Unites, SImetric system - a decimal system of weights and measures based on the meter and the kilogram and the second
Units students would used the most in high school Chemistry are grams, milliliters and centimeters. Later in the school year, moles will be used, and seconds as well.
Here is a page with commonly used metric system units, symbols and prefixes:
This video provides a useful pneumonic for remembering the metric prefixes and a guide for converting metric measurement units:
By the way, I do instruct students to put a zero in front of the decimal point!
Another topic to review briefly is the use of scientific notation.
Students use scientific calculators on a regular basis. Graphing calculators are required for many high school math courses; however, programs can be saved in these calculators that would solve the problems for them. I know that the New York State Regents Examinations in Chemistry and Physics do not allow the use of graphing calculators for this reason.
It is the teacher's choice on what type of calculator to allow in the classroom. Consult with the other teachers in your department, or the head of your science department, to determine the calculator guidelines being used.
For a standard scientific calculator, it's worth it to instruct your students NOT to press the 10 X button, but to use the EE or EXP button. When pressed, " x 10" will show up on the calculator screen and the power of ten can be entered. I highly recommend that you have a 5 minute lesson with your students or they will use their calculators incorrectly and answers will be off by a power of 10!
Here's a 10 minute video showing various examples relating to the conversion of numbers and calculations with scientific notation:
For example, instead of 637,000 it would be reported as 637 000 .
Adding and subtracting in scientific notation requires that the numbers be put into the same power of 10 (the same exponent). Then the addition and subtraction is relatively easy. Chemistry students most likely will be multiplying and dividing numbers in scientific notation. Here is a brief 7 minute video discussing all of these skills:
Here are a few worksheets to practice this important skill.
These two pages contains basic conversion problems with answers:
Here's a page with multiplying/dividing practice -- with answers!
This two-page worksheet contains scientific notation practice as well as math problems in scientific notation:
This web page contains a mixture of worksheet options:
Remember to purchase my lab book "Chemistry on a Budget" . It is available at amazon.com and lulu.com for only $20! The book contains 13 labs that require consumable materials you can purchase at local stores.
Each lab is presented with two possible report formats -- both labs use the same procedure but each has a different conclusion -- one with 10 questions to be answered as a conclusion, the other with a full laboratory report required. This gives the teacher the option of what type of report is desired, and each version is designed to be just two pages. This way the teacher can photocopy just one 2-sided page per student (saves paper).
Many of you are heading back to school, setting up your classrooms, and preparing for your first days -- some of you may even be starting classes this week. For those teachers, have a great school year! BTW, I'd love to hear from you with your questions or suggestions for blog topics.
Have a great week!