# [S3] Lesson 31 : Wave EOY Revision + (AM) Trigo Graphs + Metals II Updates/Debrief

[S3 Physics PMCians]

What we did in 2 hours:

On 30th July, 1st and 2nd Aug, the S3 PH has come together to complete the following:

1) Secret Enclosed – Waves

2) The Final Lap – Waves

Three things to remember:

1. Analysis of displacement-time and displacement-distance graphs

2. Types of waves – Longitudinal and Tranvserse

3. Speed of waves decreases in the shallower region.

Now do remember to always bring your Secret Enclosed AND the revision books for all lessons.

In this coming week (Aug 5, 8 and 9), we will begin our revision on Light I – Reflection and Refraction.

Special Mention:

Should you need assistance in your daily practices in Physics, do send your attempted workings and questions to 9100 1235. We will strive to clarify your doubts.

From the S3PH Team

(Mr Shane, Dr Li and Mr Gary)

[S3 Maths PMCians]

What we did in 2 hours:

This week, we covered on Trigonometry Graphs. We learnt the graph of y = sin x, y = cos x and y= tan x by understanding from ASTC diagram.

For y = a sin bx + c , we also discovered how the constants a, b and c affect the graphs. With these constants, we can tell:

1)      If the graph is inverted

2)      Period of the graph

3)      Amplitude of the graph

4)      Range of the graph

5)      Maximum/Minimum/Equilibrium line

Watch out for the “window” (domain) given in the question!

Please try the Takeaway Questions (Trigonometry Graphs) as homework before referring to the solutions.

Special Mention:

In the next chapter, we will look at Trigonometry Equations. Recall in Emaths trigonometry, we have already learnt to solve angles. Now, we want to solve for ALL possible angles. See you in class!

Your friendly PMC S3 Math tutors

[S3 Chemistry PMCians]

What we did in 2 hours:

We applied our knowledge on the reactivity series on metals to justify several different reactions involving metals including displacement and reactions with acids/water/steam (i.e. remember your bookmarks – metals stop reacting with cold water before C, steam before Pb and acid before H!)

You may now complete your take home package on Metals to Pg 4 and the Structured Question on Pg 9.

Special Mention:

Continue to recall your reactivity series well as we will be using it one last time this coming weekend on extraction of metals from ores and prevention of rust! Here’s a quick video on how iron is extracted from its ore of haematite: