The document discusses various measurement and calculation concepts in science including units, accuracy, precision, significant figures, and dimensional analysis. It provides examples of calculating percent error and guidelines for determining the number of significant figures in measurements and calculations. Various practice problems are included for converting between units and performing calculations while maintaining the appropriate number of significant figures.
Your science teacher has just asked you to solve some problems using dimensional analysis….OMG! What is dimensional analysis??
Don't sweat it! Dimensional Analysis (DA) is just a fancy term for converting one unit to another.
You use dimensional analysis in all the sciences from biology to chemistry and physics. You use DA anytime you need to convert one unit to another unit.
Just think "measurements need to have two parts - a number and a unit". For example, if you said "My heart beats 60" that would make no sense! Do you mean 60 beats per second or 60 beats per minute? At 60 beats per second you are probably in good health. But at 60 beats per minute, you could be a very sick person!
That's why measurements in science are composed of two parts - the quantity or numerical part and the dimension. The dimension can be time and distance, length, weight and mass, temperature, area, etc
Your science teacher has just asked you to solve some problems using dimensional analysis….OMG! What is dimensional analysis??
Don't sweat it! Dimensional Analysis (DA) is just a fancy term for converting one unit to another.
You use dimensional analysis in all the sciences from biology to chemistry and physics. You use DA anytime you need to convert one unit to another unit.
Just think "measurements need to have two parts - a number and a unit". For example, if you said "My heart beats 60" that would make no sense! Do you mean 60 beats per second or 60 beats per minute? At 60 beats per second you are probably in good health. But at 60 beats per minute, you could be a very sick person!
That's why measurements in science are composed of two parts - the quantity or numerical part and the dimension. The dimension can be time and distance, length, weight and mass, temperature, area, etc
Fisika Bilingual Besaran dan Satuan Kelas 7Frank Nanda
Ini adalah LKS (Lembar Kerja Siswa untuk Bab.Besaran dan Satuan di Kelas 7. Untuk memberi siswa wawasan lebih luas tentang kata-kata pada fisika yang ada di luar negeri.
8. Metric System Commonly Used Prefixes kilo k 1,000 10 3 hecto h 100 10 2 deka da 10 10 1 no prefix 1 10 0 deci d 0.1 10 -1 centi c 0.01 10 -2 milli m 0.001 10 -3 micro µ 0.000001 10 -6 nano n 0.000000001 10 -9
15. Monday Sept 27, 2010 Scientific Notation Allows us to write very big and very small numbers
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22. Dimensional Analysis – converting from one unit to another ex: feet/sec to miles/hour Tuesday September 28, 2010
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Editor's Notes
Measurements are made up of both accuracy and precision Accuracy, how close the measured value is to the accepted value Precision, how finely divided the measurement scale is on the device
How close a measurement is to the accepted value When ever a measurement is taken, there is always a chance for human error
How finely divided the measurement scale is on an instrument Repeated measurements should yield nearly identical values A set of measurements can be accurate without being precise, precise without being accurate, neither accurate nor precise, or both accurate and precise
All scientists use these to measure
All units are multiples of ten Consist of base unit and prefix
Give students handout with these rules
Every number written in scientific notation has two basic parts. The first part is always a decimal number between 1.00 and 9.99… The second part is 10 times some exponent Notice that in each of these, the first part is a decimal number between 1.00 and 9.99… the exponent on the 10 tells you which direction to move the decimal and how many times it should be moved. POSITIVE EXPONENT means move RIGHT NEGATIVE EXPONENT means move LEFT
The first part has to be between 1.00 and 9.99... Move your decimal until you have a number that qualifies 7.82 Remember that the exponent tells you the number of spaces that you moved it. So the answer is either 7.82 X 10 6 or 7.82 X 10 -6 A standard notation number LOWER than 1 means NEGATIVE exponent A standard notation number GREATER than 1 means POSITIVE exponent
Simple unit conversions
We need a conversion factor, a relationship between the units These both give us a relationship between in. and ft.
The great thing about dimensional analysis is that sometimes you can solve problems without equations. Here is such a case:
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![Measurement ,[object Object],[object Object],Ex: 1 mile 10.0 grams 450.00 mL](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)