Saturday 16 June 2012

How to convert units using SI prefixes?



Example:      3 cm =  _____ µm


1.   Write the equivalent factor of the prefix which you wanted to convert.
cm = cm which can be written as, cm = 10-2m
µm = µm which can be written as, µm = 10-6m


Notice that prefixes centi and micro are replaced with its equivalent factors 10-2 and 10-6 respectively.


2.   Use the units and the equivalent factors in your solution. Study and follow the arrangement below.

3 cm x 10-2m  x _µm_
           1cm      10-6m


Notice that units 1cm and 10-6m are written as denominators so that cm and m units can be cancelled.  
         
3.   Multiply all factors in the numerator, 3 cm x 10-2m  x _µm_, and all factors in the denominator, 1cm  x  10-6m. 


               cm x 10-2m  x _µm =  0.03 µm
                       1cm      10-6m          10-6


4.   Simplify by dividing the numerator and denominator.

0.03 µm = 30 000 µm or 3 x104 µm
   10-6




Prepared by:  Dante C. Arboleda
                      GSCNHS teacher I


Wednesday 13 June 2012


Significant figures, also called significant digits,  are those digits that carry meaning contributing to its precision. The concept of significant figures is used in rounding numbers into much precise answers. 


Rules for Significant Figures

1. Digits from 1-9 are always significant.
2. Zeros between two other significant digits are always significant
3. One or more additional zeros to the right of both the decimal point and another significant digit or nonzero digits are significant. 
4. Zeros used solely for spacing the decimal point (placeholder) are not significant.

EXAMPLES
# OF SIG. DIG.
COMMENT
453 kg
3
All non-zero digits are always significant.
5057 L
4
Zeros between 2 sig. dig. are significant.
5.00
3
Additional zeros to the right of decimal and a sig. dig. are significant.
0.007
1
Placeholders are not sig


Adding and Subtracting
RULE: When adding or subtracting your answer can only show as many decimal places as the measurement having the fewest number of decimal places.
Example: When we add 3.76 g + 14.83 g + 2.1 g = 20.69 g
We look to the original problem to see the number of decimal places shown in each of the original measurements. 2.1 shows the least number of decimal places. We must round our answer, 20.69, to one decimal place (the tenth place). Our final answer is 20.7 g


Try:                        a. (1.650 m) + (3.0 m) =
                                b. (3.0 x104 g) -(6.889 x103g) =
                


Multiplying and Dividing
RULE: When multiplying or dividing, your answer may only show as many significant digits as the multiplied or divided measurement showing the least number of significant digits.


Example: When multiplying 22.37 cm x 3.10 cm x 85.75 cm = 5946.50525 cm3
We look to the original problem and check the number of significant digits in each of the original measurements:

22.37 shows 4 significant digits.
3.10 shows 3 significant digits.
85.75 shows 4 significant digits.

Our answer can only show 3 significant digits because that is the least number of significant digits in the original problem.
5946.50525 shows 9 significant digits, we must round to the tens place in order to show only 3 significant digits. Our final answer becomes 5950 cm3.

Try:                        a. (1.650 m)  (3.0 m) =
                                b. (6.0 x104 g) (2.5 x103g) =

Tuesday 12 June 2012


Why we must celebrate Philippine Independence Day on June 12?

                       Filipinos are celebrating Independence Day after General Emilio Aguinaldo and Filipino revolutionary forces declared independence on June 12, 1898 from the Spanish colonization. It was the day when Emilio Aguinaldo himself for the first time raised Philippine flag and played Philippine national anthem at Kawit, Cavite on the mentioned year. However, the declaration of the liberty was not recognized by the United States and Spain until war between two countries ended on 1898 through Treaty of Paris. Spain then surrendered the Philippines to United States.


                    Filipinos were so determined to achieve sovereignty against United Sates. On June 2, 1899, the first Philippine Republic officially declared and war between the two countries officially ended on July 04, 1902.

                    Independence Day was observed on July 4 until the Republic Act No. 4166,
signed by past President Diosdado Macapagal on August 4, 1964 which set out to move the holiday on June 12 as official Independence Day.

Sunday 10 June 2012

Election of YES-O Officers will be on Friday, June 16, 2012.

 Astrophysics and Environment Seminar at CDO


Dante C. Arboleda,participant from Division of General Santos City attended the astrophysics and environment awareness seminar at Capitol University, Cagayan de Oro City last May 17 - 18, 2012. 

The two-day seminar focused on the current issues related to environment specifically global warming. Dr Theta C. Ponce, speaker from University of Asia and the Pacific, stressed on her discussion about possible solutions on how to address global warming. She discussed ways on how to cut off greenhouse gases (GHG's) and gave latest points about astronomy. The speaker also encouraged the teachers to use their knowledge gained in this program to use it as their tool in teaching science subjects.
 
The the activity was attended by 58 science teachers representing each division in Mindanao. 

GSCNHS YES-O joins Tree Planting



              Youth for Environment in Schools Organization (YES-O) joined the Tree Planting Activity and Environment Awareness Seminar at Silway 8, Polomolok, South Cotabato, Philippines on June 09, 2012.

              The Activity and Seminar were organized by Philippine Youth Leadership Program (PYLP) alumnae, Nikkilyn Sumagaysay, a bona fide student of General Santos City National High School-Engineering and Science Education Program (GSCNHS-ESEP).
              The mentioned activities were participated by the various organizations and NGO’s. Among were, GSCHS-YES-O, Brgy. Officials of Silway 8, Women Organization of Silway 8, PYLP alumni and Students of Silway 8 National High School of Polomolok.
              The activity stated 6:30 in the morning having tree planting along the highway of Polomolok. After which, the participants were gathered at Silway 8 gymnasium for a seminar with guest speaker Dante C. Arboleda.
              The main objective of the said activities is to inform the community about the importance of planting trees in their respective vicinity.