Wednesday, August 26, 2009

The Blessed Month

Today is the fifth day of the school holidays, so there's nothing to write about school. I hope all the teachers and students are enjoying their holidays. It is really a much needed rest for all of us. The Form 3 students must be working hard coz the PMR exam is coming soon. The Form 5 students also must use the free time wisely to prepare for the trial and SPM examination.

Today is also the fifth day of the fasting month. Starting Ramadhan during the school holiday is really a blessing. I don't need to rush in the morning to go to work. I'm also able to spend more time with my youngest son. This year is the second year he is fasting. Last year he only missed a day of fasting. I'm really proud of him. Hopefully this year he'll be able to complete the whole month of Ramadhan. This year is also the first year he is going to the mosque for the tarawih prayers. He looks forward to go the mosque every night partly because he likes to pray with his friends and partly because of the food that is served after the prayers.

Today I also did a talk on'teknik menjawab soalan' for SPM Mathematics for the children of the staff of the Public Works Department in Kuala Lumpur. This is my first time giving the talk. Overall, it went quite well. The students were very nice. I hope they'll gain something from my talk. As most students and teachers are aware, one of the most effective way to prepare for the SPM examination is to do the past years exam papers. Each year the format and the type of questions are the same. To be good in Math, students need to do a lot of exercises. There's a whole lot of trials exam papers that can be downloaded from the net.

Thursday, August 20, 2009

Ramadhan's Coming

The fasting month of Ramadhan is fast approaching. It was confirmed today that the fasting month will start this Saturday. I love the month of Ramadhan. Everything seems so relaxed and peaceful during this month. I don't have to rush like the regular days. I don't have to think about what to eat for breakfast and lunch. I also seem to eat less in this month and thus feel much healthier. Fasting is good for our health. We are able to enjoy the food we have coz we were deprived of it for the whole day. We humans like to take things for granted. We never appreciate the things that we have. Everyone will also make a point to make it home on time to break fast together. Thus the fasting month is also good in strengthening the family ties.

Tomorrow is also the last day of school before the school holidays. The school will be closed for holiday for 1 week from 22 - 31 August. The form 4 classes just finished the August test on Tuesday, so I gave them a day off from lessons on Wednesday. I had to carry on with my lessons with my 5SA class coz the trial exam will start on the 4th of August and I still have a few topics on Earth As A Sphere to cover.

So on Monday, I taught the girls how to find the distance between 2 point on the meridian. These are the steps:

1. Find the difference in angle between the two points.
2. Use the formula Distance = difference in angle x 60 to obtain the distance.

The unit for distance on the sphere is nautical miles (nm). The same steps can be used if you want to find the distance between two points on the equator.

Problem 1 : Find the distance between the following points :

A (85°N , 105°E) and B (27°N, 105°E)

Solution :

Note that points A and B are on the same longitude or the same meridian.

Step 1 : Find the difference in angle between the 2 points. Since the 2 points are in the same hemisphere, substract the latitude of both points to obtain the difference in angle between 2 latitudes.

Difference in angle is (85 - 27) = 58°.

Step 2 : Use the formula Distance = 58 x 60 = 3360 nm.

Problem 2 : Find the distance between the following points

A (30°S , 50°W) and B (15°N , 50°W)

Step 1 : Find the difference in angle. Since the 2 points are in a different hemisphere, we have to add the angles of the two latitudes to obtain the difference between the 2 points.

Thus the difference in angle is (30° + 15°) = 45°

Step 2 : Distance = 45 x 60 = 2700 nm.

The same steps can be use to find the distance between 2 points on the equator.

Example : Find the distance between A (0° , 14°E) and B (0° , 15°W)

1. Difference in angle (14 + 15) = 29 - Different side of the meridian
2. Distance = 29 x 60 = 1740 nm

Saturday, August 15, 2009

Schooling On A Saturday

Today is a school day. It is suppose to be a replacement day for the extended holiday the school will be taking for the Deepavali celebration in October. Schooling on a Saturday is not a good idea as proven by the poor attendance of students today. There's only 4 girls present in 5KA and only a handful in my 4SA class today. Merit marks were given to all students who were present today.

My 4SA class was taken over by the physics teacher. The students needs more help in Physics than in Math. As for my 5KA class, I continued with the Earth As A Sphere chapter. Lesson was a breeze today compared with the regular days where I have to handle 23 boisterous girls who doesn't know the meaning of quiet. Its sure is a challenge teaching these girls but I enjoy every minute of it. Today we tried some problems on determining the location of places on the earth's surface.

Any location on Earth is described by two numbers--its latitude and its longitude. If a pilot or a ship's captain wants to specify position on a map, these are the "coordinates" they would use. Actually, these are two angles, measured in degrees, "minutes of arc" and "seconds of arc." These are denoted by the symbols ( °, ', " ) e.g. 35° 43' 9" means an angle of 35 degrees, 43 minutes and 9 seconds (do not confuse this with the notation (', ") for feet and inches!). A degree contains 60 minutes of arc and a minute contains 60 seconds of arc--and you may omit the words "of arc" where the context makes it absolutely clear that these are not units of time.

To determine the latitude of a location, imagine that the Earth is a transparent sphere (actually the shape is slightly oval; because of the Earth's rotation, its equator bulges out a little). Through the transparent Earth (drawing) we can see its equatorial plane, and its middle the point is O, the center of the Earth.

To specify the latitude of some point P on the surface, draw the radius OP to that point. Then the elevation angle of that point above the equator is its latitude λ--northern latitude if north of the equator, southern (or negative) latitude if south of it. In the diagram below, the latitude of P is 30°N.

Longitude is distance east or west of a base line called greenwich meridian or prime meridian. The longitude of any given place is its distance, measured in degrees of arc, from this base line.

Thursday, August 13, 2009

Longitude and Latitude

Started the Earth As A Sphere topic by explaining the concept of longitude and latitude.

Lines of latitude run East & West or horizontal but measure distance North & South of the Equator—vertically. The equator is labeled as zero degrees latitude. The greatest amount of latitude is 90 degrees at the North or South poles. We can then label our equator as 0 and our North and South poles as 90. These lines of latitude are parallel to the equator and are even referred to as “parallels” or “parallels of latitude.”

Moving to lines of longitude, they run perpendicular to lines of latitude. That is, longitude lines run North and South but measure East and West of zero degrees longitude which is a line called the Prime Meridian. This arbitrary north/south line was marked by the British in the 17th century and runs through a town just outside of London called Greenwich.

Starting at the Prime Meridian, we measure the earth east or west with these north/south-running lines called “meridians.” We can measure halfway around the world till these meridians meet at 180 degrees. This meridian line at 180 east or west is called the International Date Line. So unlike latitude, where the greatest or maximum latitude is 90 at either the north or south poles, the greatest amount of longitude is 180—halfway around the world from the prime meridian. One other important way these longitude lines differ from parallel latitude lines is that lines of longitude are not parallel, and in fact converge at both the North and South poles.

You can read more on longitude and latitude below :
What Is Longitude and Latitude?

Tuesday, August 11, 2009

Back To School

We're back in school today after a 1 week break. Had a short assembly in the gallery. Pn Loh reminded the students on the Influenza A (H1N1)again. It seems to be getting worse as the death toll from Influenza A (H1N1) rose to 38 today. Some of the students and teachers were wearing masks. You can read more about using face mask here.

The August test is postponed to next week. That's good news for the Form 1, 2 and 4 students, they'll have more time to prepare for the test.

I still have one more chapter to cover for my form 5 class. It's the Earth As a Sphere chapter. A lot of students find this chapter quite difficult. Luckily students can choose not to answer the question on this topic for the SPM. Most probably my 5KA students will also give this topic a miss. So I won't be spending too much time on it. Hopefully by the mid term holidays, I'm able to complete the syllabus. I'm very happy with the progress shown by some of the girls in this class. It shows that nothing is impossible if you put your heart and mind to it.

Wednesday, August 5, 2009

School's Out

School is off for a whole week due to the increasing number of students and teachers getting sick. Hopefully its just the regular flu and not caused by the Influenza A (H1N1) virus. Teachers and students are instructed to quarantined themselves at home for the whole week. I hope everyone will follow the instruction given by the authorities. Anyway, the August test was postponed to the last week before the school holidays. Use the time wisely to prepare for the test and the BIG exams that are coming soon. I'm putting up some mathematical jokes I found to lighten up the atmosphere :

1. Math problems? Call 1-800-[(10x)(13i)^2]-[sin(xy)/2.362x].

2. If I had only one day left to live, I would live it in my statistics class: it would seem so much longer

3. It is proven that the celebration of birthdays is healthy. Statistics show that those people who celebrate the most birthdays become the oldest.

4. Q : Why was the maths book unhappy A : It had too many problems

5. Teacher: "Who can tell me what 7 times 6 is?"
Student: "It's 42!"
Teacher: "Very good! - And who can tell me what 6 times 7 is?"
Same student: "It's 24!

6. Q: How does a mathematician induce good behavior in her children?
A: `I've told you n times, I've told you n+1 times.

7. Student Howler 1: An average is a thing that hens lay their eggs on - for example, "My hens lay four eggs a week on average."

8. A professor, when asked how many problems there would be on the final, turned to the student and replied, "I think you will have lots of problems on the final."

9. What keeps a square from moving? Square roots, of course.

10. Teacher : If you had one dollar and you asked your father for another, how
many dollars would you have?

Student : One dollar.

Teacher : You don't know your arithmetic.

Student : You don't know my father !

Happy Face Math