Lower Secondary Science

[Dr.033430Daniel]

superkiasume:

Dr.Daniel:

[quote=\"superkiasume\"]Hi Dr Daniel,


I still have some lower secondary guidebooks from my elder child. Since the change in syllabus is minimal, does it mean that these guidebooks can still be used for my younger child, going into secondary 1 next year?

[/quote]Yes I think as a starting point they can be used. There look to be a couple of topical changes within the new textbooks, but the majority of it is the same.

If you have a student going into Sec1 and they are going to start with physics, make sure they know the metric system as soon as possible. How to convert cm to mm, and m to km and speeds like m/s to km/hr. If they are solid on the metric system, then they have a better chance of understanding the rest of the physics that follows.

[Herbie]

Dr Daniel

Under wat circumstances do we use sin r/sin i for calculation of refractive index? Can advise? Tq

[Dr.033430Daniel]

Herbie:

Dr Daniel

Under wat circumstances do we use sin r/sin i for calculation of refractive index? Can advise? Tq

That looks like a special case of Snell’s Law.

I recommend that students learn the full Snell’s law which is ni sin i = nr sin r. Since diagrams are helpful in explaining this, you can see three solved problems at the following link:

http://www.physicsandcalculus.com/2012/snells-law-problems

[weatherbee]

superkiasume:

Does anyone know if there will be a change in the syllabus for lower and upper secondary science for next year?


I am thinking of buying books in advance for my kids.

Yes, there will be a slight change in syllabus.

[bandmate]

Herbie:

Dr Daniel

Under wat circumstances do we use sin r/sin i for calculation of refractive index? Can advise? Tq

The textbook do not show the full version of Snell's law and it is taken that the circumstance only involve water and air(where the refractive index is approximately 1). For sin r/sin i situations, the circumstance is usually when light have to travels from an optically denser medium like water, to an optically less dense medium like air. So in this case, they reversed it so that you have the angle to the normal from the optically less dense medium to be always at the top of the fraction. When light travels from water to air, the angle of incidence (of the water) is always lesser than the angle of refraction (of the air) with respect to the normal. Therefore, by using sin r/sin i, sin r is always bigger than sin i which gives a value of greater than 1 usually. This tallies with the fact that n is always 1 or greater than 1. Hope this helps.

[bandmate]

bandmate:

Herbie:

Dr Daniel

Under wat circumstances do we use sin r/sin i for calculation of refractive index? Can advise? Tq

The textbook do not show the full version of Snell's law and it is taken that the circumstance only involve water and air(where the refractive index is approximately 1). For sin r/sin i situations, the circumstance is usually when light have to travels from an optically denser medium like water, to an optically less dense medium like air. So in this case, they reversed it so that you have the angle to the normal from the optically less dense medium to be always at the top of the fraction. When light travels from water to air, the angle of incidence (of the water) is always lesser than the angle of refraction (of the air) with respect to the normal, unless the light travels perpendicular to the plane on which the light hits. Therefore, by using sin r/sin i, sin r is always bigger than sin i which gives a value of greater than 1 usually. This tallies with the fact that n is always t1 or greater than 1. Hope this helps.

[Herbie]

bandmate:

Herbie:

Dr Daniel

Under wat circumstances do we use sin r/sin i for calculation of refractive index? Can advise? Tq

The textbook do not show the full version of Snell's law and it is taken that the circumstance only involve water and air(where the refractive index is approximately 1). For sin r/sin i situations, the circumstance is usually when light have to travels from an optically denser medium like water, to an optically less dense medium like air. So in this case, they reversed it so that you have the angle to the normal from the optically less dense medium to be always at the top of the fraction. When light travels from water to air, the angle of incidence (of the water) is always lesser than the angle of refraction (of the air) with respect to the normal. Therefore, by using sin r/sin i, sin r is always bigger than sin i which gives a value of greater than 1 usually. This tallies with the fact that n is always 1 or greater than 1. Hope this helps.

Thanks!

[shurley197323]

Hi, I am looking for a Science Dictionary. Anyone know where to buy or seem it before ? I could not find it at Popular. Thanks

[Dr.033430Daniel]

shurley197323:

Hi, I am looking for a Science Dictionary. Anyone know where to buy or seem it before ? I could not find it at Popular. Thanks

This post got me looking because I want to get a dictionary like this also. I found that Oxford has one. The link is below. I have a copy of the regular Oxford English Dictionary in my classroom and always encourage the students to look up a word if they don't know it. I'm going to get the science one myself also and check it out.

Here's the link to Amazon:

http://www.amazon.com/Dictionary-Science-Oxford-Paperback-Reference/dp/019956146X/ref=dp_ob_title_bk

And I also found it at Kinokuniya:

http://www.kinokuniya.com/sg/index.php/fbs003?common_param=9780199561469

[shurley197323]

Dr.Daniel:

shurley197323:

Hi, I am looking for a Science Dictionary. Anyone know where to buy or seem it before ? I could not find it at Popular. Thanks

This post got me looking because I want to get a dictionary like this also. I found that Oxford has one. The link is below. I have a copy of the regular Oxford English Dictionary in my classroom and always encourage the students to look up a word if they don't know it. I'm going to get the science one myself also and check it out.

Here's the link to Amazon:

http://www.amazon.com/Dictionary-Science-Oxford-Paperback-Reference/dp/019956146X/ref=dp_ob_title_bk

And I also found it at Kinokuniya:

http://www.kinokuniya.com/sg/index.php/fbs003?common_param=9780199561469

Sure,thanks a lot Dr Daniel. I will go to Kinokuniya for a look. Amzaon shipping to Singapore is quite high.