Dante's Best

Projectile Motion

2016-10-06T06:57:00.002-07:00

For G9 Mendeleev and Rutherford. Solve the following in 1 whole piece of paper and pass it tomorrow, October 7, 2016,12 noon

Problem 1: A rock is thrown with an initial vertical velocity component of 30 m/s and an initial horizontal velocity component of 40 m/s.

a. What will these velocity components be one second after the rock reaches the top of its path?

b. Assuming the launch and landing heights are the same, how long will the rock be in the air?

c. Assuming the launch and landing heights are the same, how far will the rock land from where it was thrown?

Problem 2: Two tennis ball launchers shoot balls at the same time, angle and initial speed from different floors of a tall building. The balls land in the street below. Ignore air resistance.

a. Which ball will have the greater acceleration while in flight? Explain your reasoning.

b. Which ball will hit farther from the base of the building? Explain your reasoning.

c. Which ball will reach a greater maximum height? Explain your reasoning.

d. Which ball will be going faster just before hitting the street? Explain your reasoning.

e. How could you adjust only the angle of the upper launcher so that the ball hits in the same place as the ball from the lower launcher? Explain your reasoning.

f. How could you adjust only the angle of the lower launcher so that the ball hits in the same place as the ball from the upper launcher? Explain your reasoning.

Problem 3: Balls A and B are launched from different heights. The reach the same maximum height at exactly the same point in space.

a. Which ball has a greater initial vertical component of velocity? Explain.

b. Which ball has a greater initial horizontal component of velocity? Explain.

c. Which ball has the larger launch angle? Explain.

d. Which ball has greater acceleration while in flight? Explain.

e. Which ball will land farther from the launchers? Explain.

f. Which ball takes longer to reach maximum height? Explain.

g. If the balls were launched simultaneously, would they collide before landing? Explain.

Problem 4: If a person can jump a horizontal distance of 3 m on Earth, how far could the person jump on the moon where the acceleration due to gravity is one-sixth of that on earth (1.7 m/s/s)?

Problem 5: A brick is thrown upward from the top of a building at an angle of 25 degrees above the horizontal and with an initial speed of 15 m/s. If the brick is in the air for 3 seconds, how high is the building? (Draw a picture.)

Problem 7: A daredevil tries to jump a canyon of width 10 m. To do so, he drives his motorcycle up an incline sloped at an angle of 15 degrees. What minimum speed is necessary to clear the canyon?

Nuclear Fusion On the Sun

2013-09-17T06:50:00.000-07:00

Hello everyone. I'd like to share a Youtube video which might help you in understating what nuclear fusion is.

Nuclear Fusion is the process of fusing light atoms into more heavy atom through a tremendous pressure. The higher pressure (150 atmosphere) will increase the temperature which will make fusible atoms more exited and causing them to bump and fuse. As the atoms fused, it produces energy.

Radioactivity

2012-08-23T04:27:00.000-07:00

For IV -Rizal and IV -Gomez

Please check this video. This could improve your performance during our class discussion.

Enjoy and Good luck.

Cells to organism

2012-08-22T06:03:00.000-07:00

Quarter 2, module #1... Cell to organism.

METALS AND NONMETALS

2012-08-06T08:01:00.001-07:00

Elements are the simplest form of substances. This means that whatever you do with an element, it remains to be the same element. Its physical state may change but the identity of the element will not. It may form compounds with other elements but the element will never form anything simpler than it already is.
There are already more than a hundred elements and are organized in a Periodic Table. Some of them are naturally occurring and some were produced in a laboratory.

         In this module, you will find out more about the elements. You will see that majority of them are metals, and almost the rest are nonmetals.

How are metals different from nonmetals?
How are they similar?

           In the earlier grades, you segregated objects according to the material they are made of. You did this when you were starting the habit of 5Rs — recycle, reuse, recover, repair or reduce. Look around you. Which objects are made of metals? What made you say that they are metals?

          Perhaps, you have been identifying a metal based on its appearance. Most of the time, metals are shiny. They exhibit a certain luster.

Other properties exhibited by some metals
             Some metals are ductile. This means that metals can be drawn into wires. An example is copper. Refer to the figure on the right. Note the form at which copper is mined. However, due to its ductility, copper may assume a form similar to a wire, just like the image in the cover of this module. Gold is also a metal that is ductile; however, it is rarely used as an electrical wire. What could be the reason for this?

             Some metals are malleable. This means that they can be hammered or rolled into thin sheets without breaking. An example is aluminum. It is mined deep from the ground in the form of blocks. They are passed into mills and rolled thinly. One common form is the aluminum foil that you use to wrap food to keep it hot. Most soda cans are made of aluminum too. Find a soda can and strike it with a hammer. What happened with the soda can?

             Some metals are magnetic. This means that they are attracted by a magnet. The common ones are iron, nickel and cobalt. Get a magnet. Try them in different metals in your home or school. Were they all attracted to the magnet? What metals are these?

             Metals are known to possess luster, ductility, malleability and magnetic properties. However not all metals exhibit all of these properties. For instance, the metals sodium and potassium are not ductile at ordinary conditions. They are very soft that even a kitchen knife can cut them into slices as what you can see in the image on the right. Note though that only experts are allowed to do this. Recall what you have learned in module 4 about sodium when it comes in contact with water. Zinc at room temperature is not malleable. Most of the metals are not attracted by a magnet. Nevertheless, a material is still considered a metal as long as it possesses any of these properties. A material that does not possess any of these properties is known as a nonmetal.

Properties exhibited by all metals
         But are there properties that are common to all metals?

         Electrical conductivity is property of metals that allows electricity to pass through a material.

           The metallic probe in the figure on the right is the one that comes in contact with the sample. It will measure then display the electrical conductivity value in the liquid crystal display (LCD) screen. Refer to the periodic table found at the back page of this module. The electrical conductivity values are written at the bottom line of each box. It is expressed in x106 Ohm-1cm-1. What do you notice about the elements with electrical conductivity values? Where are they located in the periodic table?

            One amazing feature of the periodic table is that all the metals are placed in one side. Those that are on the other side (grayish shade) are the nonmetals.

        Notice that there is a stair step line which somewhat divides the metals and nonmetals. These elements are the metalloids. They are elements exhibiting properties that are intermediate to metals and nonmetals. Name the metalloids. Name some metals. Name some nonmetals.

           Which are electrically conductive, metals or nonmetals? Which element has the highest electrical conductivity value? Is it higher than copper? If so, what could be the reason for using copper as an electrical wire more than this element?

           You might wonder why some metals do not have electrical conductivity values when supposedly all of them possess such property. Notice that these metals are the ones mostly found at the last rows of the periodic table. Elements in those rows are mostly radioactive. This means that the element is very unstable and exists in a very short period of time. In effect, it would be difficult to test for their properties. In the higher grade levels, you will learn that there are ways to infer the electrical conductivities of these elements.
Electrical conductivity clearly distinguishes metals from nonmetals but there is one exception. Refer to the periodic table. Which element is electrically conductive even if it is a nonmetal?

           One form of carbon is graphite. It is commonly available as the black rod in your pencils. Get your sharpened pencil. Place the black rod in between the end tips of your improvised conductivity tester. Make sure that the black rod is in contact with the tips of the tester. What happened?

          In the higher grade levels, you will learn why carbon (graphite) though a nonmetal is electrically conductive.

          Look for other objects and test if they are made up of metal or nonmetal. Write down these objects in the appropriate box of the diagram below.

         Were you able to find a cooking pot as one of your test objects? What element is it mainly made of?
Refer to Table 2. This table shows the thermal conductivity values of some elements expressed in Watt/centimeter-Kelvin (W/cmK). Thermal conductivity is the ability of an element to allow heat to pass through it. The higher the value, the better heat conductor an element is. Find the element that was mainly used for the cooking pot you have. What can you say about the thermal conductivity of this element compared with the other elements? Is this element, a metal or nonmetal? In general, which are better heat conductors, metals or nonmetals? Based on Table 2, what other elements can be used as cooking pots?

Table 2. Thermal conductivities of some elements

Element                                Symbol                               Thermal Conductivity* (W/cmK)
Copper                                   Cu                                                         2.37
Iron                                        Fe                                                          0.802
Selenium                                Se                                                          0.0204
Sulfur                                     S                                                           0.00269
Phosphorus                            P                                                           0.00235

Metals and Nonmetals In and Around You
                 In the figure below, you will find the elements that your body is made up of. What element are you made up of the most? Is it a metal or a nonmetal? Of all the elements reported in the graph, how many are metals? How about nonmetals?

            Refer to the figure below. The figure shows how much of one element is present in the Earth’s crust relative to the other elements. What element is the most abundant in the Earth’s crust? What comes second? Are these metals or nonmetals?

            Refer to the periodic table. What constitutes majority of the elements, metals or nonmetals?
Interestingly, even with the fewer number of nonmetals, their abundance is higher than metals. As you have seen above from the two graphs, both living and nonliving systems are mainly composed of nonmetals.

              As you learned in module 4, elements form compounds. The percentage abundance of the elements reported in the graphs above accounts some elements that are present in compounds, much like the food ingredients you encountered in the last module. For instance, sodium is present in sodium chloride. The 18.0% carbon that makes up the human body is mostly compounds of carbon such as the DNA that carries your genetic code.

Oxides of Metals and Nonmetals
          Similarly, oxygen accounted in the graphs may also be in compounds. Some of these compounds are called oxides. These oxides may be formed when an element is burned. These oxides exhibit different acidities.

          In module 2, you learned that there are indicators that you can use to determine such. One of these acid indicators is the litmus paper. What color does the litmus paper show when the sample is acidic? How about when the sample is basic?
In the next activity, you will separately burn a sample of a metal and a nonmetal. You will test the acidity of the oxide of a metal and that of the oxide of a nonmetal.

In this module, you learned about the properties of metals and nonmetals. These properties are the ones that determine their uses like aluminum’s malleability to become soda cans, and copper’s ductility to become electrical wires.

Most of the elements are metals. Some metals are malleable; some are ductile; some are magnetic but all of them are electrically conductive. Nonmetals are electrically nonconductive except for some forms of carbon.

It is important to note though that most objects are made not of a single material, rather of a combination of materials so they become fitter for a purpose. This is where your knowledge on the properties of materials comes in. Which materials do you combine to make it fit for a purpose? As you can see from the image in this module cover, the electrical wire made of copper was covered with rubber. Rubber is mainly made of compounds of nonmetals such as carbon, hydrogen and chlorine. As you have learned, nonmetals are nonconductors of electricity. Using a nonmetal to cover a metal makes it safer to use as an electrical wire.
As you advance to another grade level, there are more properties of matter that you will encounter. It is hoped that you will be able to maximize the properties of different materials to create new beneficial products or find other uses for them.

METALS AND NONMETALS

2012-08-06T07:40:00.000-07:00

Qualified for the Final SciTech Elimination Round

2012-08-03T04:29:00.003-07:00

Congratulations to:

Earl Darwin Chester Cabiling
Stiffer Love Calawod
Ryan Joshua Vergara

Please report to I Archimedes room on August 06, 2012, 5:00 P.M for the final elimination. Good Luck guys.

ELEMENTS VS COMPOUNDS

2012-08-01T05:08:00.003-07:00

            All substances are homogeneous. Some mixtures are also homogeneous. Being so, it is difficult to distinguish mixtures and substances based on appearance. However, there are ways to tell if a sample is a mixture or a substance. The temperature of a liquid mixture changes during boiling but for a liquid substance, it does not. A solid mixture has portions that do not melt but a solid substance melts completely at a given time. From here, you can say that the more observations and characteristics you consider, the better you can classify them.
            In this module, you will find out that substances may further be classified into two: compound and element. You will start with the primary characteristic that distinguishes them.Compounds Like mixtures, compounds are also made up of two or more components.
            In module 3, you separated the components of seawater through distillation. One of the products obtained was distilled water. Also, you have identified distilled water as a substance.

How are elements different from compounds?
How are they similar?

In the video you will about to see, how to separate hydrogen and oxygen atoms of compound water.
This process is called electrolysis.

Q1. What happened when you placed a lighted match near the mouth of the test tube?

                       As you have seen from the video above, compounds are made up of components. These components are called the elements. Like compounds, the elements are also substances. However, unlike compounds, elements cannot be broken down into simpler substances. Chop a sample of an element; you still have the same substance after! Distill? You get the same! Electrolyze? Still the same!

                      Notice as well that the property of a compound is different from the properties of its constituent elements.

Elements
                     There are119 known elements. Each element has different set of properties. No two elements have the same set of properties. Just like the two elements that were generated in video above, hydrogen and oxygen. Even though they are both in gaseous state at room temperature, they behave differently when exposed to a flame or spark of flame. Hydrogen gives off a “pop” sound when ignited; while oxygen induces a brighter spark. This difference in behavior implies a difference in property. In effect, hydrogen and oxygen are different substances, or to be more specific, they are different elements.

                      119 is quite a big number! Thanks to the works of our early scientists, they were able to systematically organize all of the 119 elements in what we call the periodic table of elements or sometimes simply referred as periodic table. Amazingly, they were able to logically arrange the elements in the table enabling one to have an idea of the properties of several elements by knowing other elements related to them. This means that there is no need to memorize the periodic

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Q1. What are the symbols for elements with long names such as beryllium, phosphorus, germanium, and darmstatdtium?

a. Notice that most of the one-letter symbols are the first letters of these elements.

Q2. What are the symbols for boron, nitrogen, fluorine and vanadium?

b. For the two-letter symbols, most of them start with the first letter of the elements. Notice that the second letter in the symbol may be any letter found in the element’s name. Notice as well that only the first letter is capitalized for the two-letter symbols.

Q3. What are the symbols for lithium, chlorine, argon, calcium and manganese?

c. There are symbols that use letters that were taken from the ancient name of the element. Examples of ancient names are ferrum (iron), argentum (silver), hydrargyrum (mercury) and plumbum (lead).

Q4. What are the symbols for iron, silver, mercury, and lead?

d. In the earlier grade levels, you already encountered elements. You studied rocks and learned that some are composed of silicon and magnesium. Some even have gold.

Q5. What are the symbols for silicon, magnesium and gold?

f. When you were recycling materials, you segregated the objects according to what these are made of. Some of them are made from aluminum, copper, tin or carbon.

Q6. What are the symbols for these 4 elements?

g. In nutrition, you were advised to eat enough bananas because it is a good source of potassium.
Q7. What is the symbol for potassium?
h. In each box, you will find a number on top of each symbol. This is the atomic number. In the higher grade levels, you will learn what this number represents. For now, use it as a guide on how the elements are sequenced.
Q8. What is the element’s name and symbol that comes before titanium? How about that comes after barium?
i. Elements that are in the same column tend to have similar properties. For this, each column is called a family and has a family name. However, at this point, you will refer first to each family with their corresponding group number. Notice that the columns are numbered 1 to 18 from left to right.
Q9. In which group does each of the elements listed in Table 1 belongs to?
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                        There are other elements present in the food you eat —whether it is a natural food like bananas or those processed like banana chips, biscuits, milk, and juice. In nutrition, you have called them minerals. These are nutrients which the human body needs in order to function well. Some of these minerals are calcium, magnesium, zinc, and selenium. Find these elements in the periodic table. Can you name more? Did you find them in the periodic table?
                        Note that these minerals have to be taken in by the body in recommended amounts. Refer to Figure 3. How much calcium do you need to consume in a day? How about magnesium? Avoid taking in minerals beyond these recommended amounts. It may lead to sickness, and even death. Thus, it is imperative that you are aware of what makes up the food that you are eating. Also, make sure that you have a balanced diet. You may refer to Table 2 below for food sources of some minerals when preparing your meal
Figure 3. Recommended mineral intake (WHO, 2004)

Macrominerals

Calcium (Ca)    Milk, cheese, canned fish with bones, sesame seeds, green leafy vegetables
Essential to formation and maintenance of bones and teeth; regulates nerve transmission, muscle contraction, and blood clotting. Rickets in children; diseases of the bones in adults such as softening of the bones and decrease in bone mass
Magnesium (Mg)   Nuts, legumes, cereal grains, dark green vegetables, sea food, chocolate
Catalyst in the synthesis of energy-carrier molecules; involved in the synthesis of proteins and relaxation of muscles
Fluid loss due to too much alcohol intake; heart failure due to spasms
Potassium (K)   Orange juice, bananas, dried fruits, potatoes
Maintains regular heartbeat, water balance and cell integrity; needed in nerve transmission, carbohydrate and protein metabolism
Sudden death during fasting, poor nerve function, irregular heart beat
Selenium (Se)
Liver, meat, grain, vegetables
Part of enzymes; antioxidant
Keshan disease (heart disease)
Sodium (Na)
Meat, table salt, salt- processed food
Regulates amount of body fluid; involved in nerve transmission
Headache, physical weakness, thirst, poor memory, appetite loss
Sulfur (S)
Some proteins
Component of biomolecules and ions
Zinc (Zn)
Liver, shellfish, meat, wheat germs, legumes
Part of insulin and some 154 enzymes
Anemia, stunted growth
Microminerals or Trace elements
Chromium (Cr)
Liver; animal and plant tissues
Needed for glucose utilization
Loss of insulin efficiency with age
Copper (Cu)
Liver, kidney, egg yolk, whole grains
Helps in the formation of hemoglobin; part of 11 enzymes
Rare
Fluorine (F)
Sea food, fluorinated drinking water
Strengthens bone and tooth structure
Dental decay
Iron (Fe)
Liver, meat, green leafy vegetables, whole grains, cocoa beans
Component of hemoglobin and myoglobin
Anemia, tiredness, and apathy
Iodine (I)
Sea food, iodized salts
Part of thyroxin, regulates rate of energy use
Goiter
Manganese (Mn)
Liver, kidney, wheat germ, legumes, nuts
Cofactor for a number of enzymes
Weight loss, occasional dermatitis

                   You can also find information about the contents of the food in its product label. Usually, they are written as Nutrition Facts and Ingredients.
                 The Nutrition Facts is a list of the different nutrients provided by the food product with their corresponding percentage share on the daily recommended dietary allowance. Refer to the figure on the right. Notice that some of these nutrients are elements such as calcium. Is this food a good source of calcium?
                  On the other hand, Ingredients give you a list of the materials that have been added to create the food product. These materials are the sources of the nutrients. These are the ones that are taken in by the body. Refer to the figure below. Find the ingredient ferrous sulfate. Ferrous is another word for iron. Refer to the figure above. This is the Nutrition Facts which corresponds to the food product having these ingredients. Find the nutrient iron. How much iron does this food product give as part of the recommended dietary allowance? From this product label, you can tell that you will be getting as much as 35% of iron that you need for the day and eaten mostly as ferrous sulfate. Notice that the name of the ingredient gave a clue as to which nutrient this ingredient contains.

Cereal drink
Ingredients:
sucrose, creamer (glucose syrup, hydrogenated palm kernel oil, sodium caseinate containing milk, sequestrants, emulsifiers, nature-identical flavors, sodium chloride, anticaking agents), maltodextrin, cereal flakes (wheat flour, rice flour, malt extract, sucrose, corn grits, acidity regulator), sweet whey powder, cocoa powder, iodized salt, thickener, artificial flavour, zinc sulfate, iron pyrophosphate.
May contain traces of soya.
__________________________________________________________________________________

___________________________________________________________________________
                      As you have learned from the activity above, the minerals listed in the Nutrition Facts as elements are present in the food as compounds. Thus, you are not eating the elements themselves.
A product label that lists sodium as a nutrient does not mean that you will be eating the element sodium. It means that the composition of one of the ingredients includes sodium. In the case of soy sauce, the ingredient is monosodium glutamate.
                       It is very rare and most of the time dangerous if you take in the element itself. In Activity 1, you have seen that water did not give off a “pop” sound nor induced a bright spark when exposed to a spark or flame, unlike its constituent elements hydrogen and oxygen, respectively. This means that the properties of compounds are different from the properties of the elements it is made up of. There are cases that the properties of a compound pose less risk than its constituent elements. An example is sodium and one of its compounds. Sodium is an element that flares when it comes in contact with water. Refer to the photo above. Imagine the danger that you are in to if you will be eating sodium as an element. However, sodium chloride, which is a compound made up of the elements sodium and chlorine, does not flare when it comes in contact with water. In fact, sodium chloride is sometimes used with water as common food ingredients. Perhaps, you are already familiar with this. Does table salt ring a bell? Sodium chloride is commonly called as table salt. As you know, it is safe to eat. Do take note though that it should be consumed in the right amount. Excessive consumption of sodium chloride may lead to kidney failure. From here comes the importance of reading product labels. This will let you know how much of a nutrient you get from a food product. It is also an advantage if you know the different names of the elements and compounds. Take the case of the food product label below.
                       Refer to the Nutrition Facts of the cereal product on the right. It tells that this cereal product provides the nutrient, sodium.

                       Now, refer to the Ingredients. Do you find any ingredient that could be a source of sodium? It may seem not, at first. However, knowing that the other name for sodium chloride is salt, you can now identify one source ingredient for the sodium that is listed in the Nutrition Facts.

                      Note that there are instances that the Nutrition Facts is incomplete. You may find an element unlisted but once you check the Ingredients, you can tell that the food product could be a source of that mineral. Refer to the label of the cereal drink you used in Activity 3. Is sodium listed in the Nutrition Facts? Is there an ingredient that could be a source of sodium? When you read product labels, make sure you do not miss out on these information. This will help you decide if the product is worth buying.
Any ingredient added to food should be safe to eat in terms of quality and quantity. By quality, these ingredients must be food grade. A substance undergoes a process before it becomes food grade. It is only after that, a substance may be safely added as a food ingredient. If it is a non-food grade substance then it should not be added to products that are meant to be ingested.

Refer to the product labels for a soy sauce and a lotion. Notice that potassium sorbate is a common ingredient. It has the same function for both products, that is, it acts as a preservative so the product would last longer. However, it is important to note that food grade potassium sorbate was added in soy sauce; while a non-food grade potassium sorbate was added in lotion.

                   You can safely ingest soy sauce but never ingest the lotion. Notice that the product label does not indicate if the ingredient is food grade or not. However, there are government agencies that make sure the food products that are sold in the market uses only food grade ingredients. Thus, it is safe to assume that food products consumed in the right amount will not pose any risk.
In the next activity, you will encounter another substance that is common to materials that are not meant to be ingested. However, this substance was made food grade before it was added as a food ingredient. This substance is iron. This food grade iron is sprayed onto the food or added as a powder to the mixture. Because it is the elemental iron that was added as a mixture, its properties are retained. One of these is its magnetic property. Thus, you can recover the iron present in the food product by using a magnet.
___________________________________________________________________________

Compounds are made up of elements.
Elements are the simplest form of matter.
Both elements and compounds are substances.

___________________________________________________________________________
As you have seen, elements are part of almost anything around us — food, clothes, rocks, and even this paper you are currently reading from. Elements are said to be the building blocks of matter. They are like blocks that you can put together and build something new. When you build something new from these elements, you call them as compounds.
With the 119 elements known, imagine how many combinations of elements you can make into compounds and how diverse can the materials around us be.
In the next module, you will learn more about the elements. You will work on samples of elements and explore their properties.

2011 REGIONAL SCIENCE QUEST HELD AT KORONADAL CITY

2012-07-29T04:41:00.001-07:00

Going to Baguio!!!
General Santos City High School participants shone in the 2011 Regional Science Quest held at Carpenter Hill Elementary School, Koronadal City.

Among the participants were, Gaille Anne Surriga, Bb. Kalikasan 2011, Keefe Alfred Pulia, Ginoong Kalikasan 2011 First Runner-up, Dante C. Arboleda, Champion of the Science Intervention Material (First year level), Debbie Plana, 3rd place of the Science Intervention Material (Second year level), Arriane Magbanua, 3rd place of the On the Spot Painting and Hannahly Diaz, 5th place of the Science Quiz Bowl (biology). Among the coaches were, Rosanna Elumbaring, Shirley Regalado and Noel Baterbonia.

How to convert units using SI prefixes?

2012-06-16T08:17:00.000-07:00

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}

2012-06-13T07:19:00.001-07:00

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 x10⁴g) -(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 x10⁴g) (2.5 x10³g) =

2012-06-12T05:31:00.003-07:00

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.

2012-06-10T07:10:00.004-07:00

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

2012-06-10T06:02:00.000-07:00

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

2012-06-10T01:42:00.001-07:00

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.