Sabbatical

STEM: Energy Energised Sabbatical

1) Introduction

http://www.slideshare.net/tohcy/stem-energy-energised-day-1

In this sabbatical, we closer study renewable and/or cleaner sources of energy, such as:

1. Biodiesel from vegetable or animal oils and fats
2. Solar Energy
3. Fuel Cells
4. Wind Energy
5. Nuclear Energy
and other energy sources

Throughout the sabbatical, we were exposed to various activities involving these sources of energy.

2) Synthesis of Biodiesel

Through this activity, we learnt how to convert vegetable oil into bio-diesel oil. In this experiment, we converted different brands of vegetable oil into bio-diesel oil and compared the efficiency of the various types of vegetable oil in producing bio-diesel.

We were given a very detailed set of instructions to follow. Our group seemed to be less efficient than other groups, as we misunderstood some steps. Nevertheless, it was an enjoyable as we went though various processes throughout the experiment such as filtration and taking of measurements. Measurement-taking was very crucial here as a misreading could lead to very different results. One group sped through the experiment and got much less bio-diesel than expected, as the teacher later explained that it should have produced the most bio-diesel.

3) Activity: Green Car Race

Objective

Use different alternative source of energy to power the car and compare the efficiency of the sources

The Idea

How does the alternative energy source of energy work?

Electricity is produced by the alternative source of energy to drive the gears. When the gears move, the wheels spin, thus moving the car.

Steps:
1. Build the Car
2. Insert battery
3. Run it!!!

The type of energy sources include solar energy, fuel cells, and wind energy. It turned out that fuel cells worked best as the car was fastest. However, I reflected that this experiment might not be a fair one. For example, the "Wind Car" ran on the energy from the turning of small wind turbines, from the wind from a fan. If more wind energy was supplied, the "Wind Car" might have been faster. The controlled, independent and dependent variables were not clearly stated too.

However, this activity was quite enriching as we learnt how some energy sources could produce electricity.

Term 3

Scope of the term: Energy

 

This term, we are taught physics: Optics. Through this term we learnt a lot more about what we rely on everyday: Light. We studied the properties of light and the characteristics of different mirrors: Plane mirrors, convex mirrors and concave mirrors. We also learnt about the light spectrum resulting from different wavelengths of light.

1) Reflection of Light

We were taught the two laws of reflection:

1) The incident ray, the reflected ray and the normal at the point of incidence all lie on the same plane.

2) The angle of incidence is equal to the angle of reflection.

We were also taught how to draw a simple diagram illustrating the reflection of light through a step by step basis. After learning the basics, we were taught how to draw the reflection of light rays in convex and concave mirrors: by first constructing the tangent, then drawing the normal perpendicular to it. The same rule applies: the angle of incidence = angle of reflection.

2) Refraction of Light

We were also taught the refraction of light. Refraction, or the bending of light, happens when a light ray travels through 2 or more different medians. As the light rays travel from an optically less dense to a denser medium, the light ray decreases speed, therefore, the light ray bends towards the normal. When a light ray travels from an optically denser to a less dense medium, the light ray increases speed, therefore, bends away from the normal. We were also taught how to draw such diagrams and calculate the angle of refraction based on the refractive index, n.

There is a formula for deriving the angle of refraction:

n= sin i/sin r

n = refractive index

i = angle of incidence

r = angle of refraction

The critical angle is the angle of incidence in the optically when the angle of refraction in the optically less dense medium is 90 degrees. Any angle of incidence that is greater than the critical angle, total internal reflection occurs.

3) Total Internal Reflection

As stated previously, when an incident ray hits the optically less dense medium at an angle greater than the critical angle, total internal reflection occurs. When this happens, the light ray is reflected as if it had hit a mirror.

Applications of total internal reflection includes: Optical Fibres in Telecommunications, and in Endoscopy. A right-angled prism also allows for total internal reflection.

Lens

In lens, we were taught the definition of "focal point", "focal length" and the properties of concave and convex lenses. 

We were also taught how to draw the diagrams, and we learnt the uses of the 2 different types of lens such as the magnifying glass.

Colours of Light

 
We learnt about the visible light spectrum, consisting of 7 colours: Red, Orange, Yellow, Green, Blue, Indigo, and violet. Their wavelengths differ, resulting in changes to the speed of light during refraction. The formation of the rainbow is also due to refraction of the light rays and the splitting of light into 7 colours , then being reflected due to total internal refraction, into our eyes.

Term 3 Reflections

This term was a very fulfilling one, as we given many opportunities to understand and apply our knowledge, such as the enriching practical sessions. We were given tasks to do some hands-on work. I found it especially interesting to relate what we observe in the practicals to what we have learnt, as well as to what we see around us everyday, such as the formation of rainbows.

This term, I managed to do well due for effort spent. It was an impressive score considering that I had competition during the test period. I hope to continue to be optimistic while working hard.

Additional websites:
http://lumenistics.com/what-is-full-spectrum-lighting/

Term 2

Scope of Term 2:

1. Acids and Bases
2. Sexual Reproduction

In this chapter, I would be sharing with you my time during school term and my revision after the school term during the holidays.

Acids and Bases

In acids and bases, we learnt about the properties of acid and alkaline, as well as their effects on indicators such as the universal indicator and the red and blue litmus paper. We went through several practicals on the reaction of acids and bases with other substances. We were also required to remember some key equations such as "acid + carbonate > salt + carbon dioxide + water" and "acid + metal = salt + hydrogen". At first, this task seemed tedious for I could not quite get it. 

However, through the practicals, I started to get a slightly better understanding of the topic and could familiarize with the formulas. The practicals did give me a "boost" in memory work. We were also required to remember the colours of indicators under different pH, as well as learn how to test for products of the equations. Lots of memory and understanding required!

Definition of Acid

An acid is a substance which produces hydrogen ions as the only positive ions when it is dissolved in water.

The strength of Acids depends on its degree of dissociation / ionization in water to form hydrogen ions.

A pure acid does not have the corrosive properties alone. These properties occur only when there is ionization to produce hydrogen ions, or in other words, when acid is dissolved in water.

Definition of  Bases and Alkali

Bases are the oxides or hydroxides of metal that reacts with an acid to form salt and water only.

Where else, An alkali is a metal hydroxide which is soluble in water and produces hydroxide oxides (OH-) in water.

Therefore, all alkali are bases but not all bases are alkali.

Types of Oxides include Acidic oxides, Basic Oxides, Neutral Oxides and Amphoteric Oxides. Acidic oxides are non-metallic, while Basic Oxides are metallic. Both require the presence of water to show Acidic and Alkaline properties.

The strength of Alkali depends on its degree of dissociation/ionization in water to form hydroxide ions.

Writing Chemical Equations

After learning the equations to how acids and bases react to different substances, it is time for Balancing of Equations! This part of the topic of acids and bases was the most interesting. At first it would seem confusing, but after several rounds of practice, and understanding the formula of ionic compounds, the task would be easy. This also required the understanding of Term 1's topic of cation and anions. 

Sexual Reproduction in Plants

In sexual reproduction in plants, we are required to memorize facts, make logical inferences as well as make observations. We learnt pollination and fertilization, the processes withing them, and the plant parts supporting the processes. Therefore, in my opinion, memorizing the facts had the largest component for this topic. However, there were activities to enrich our learning. For the practicals, we explored the school campus for different types of flowers and classified them according to their method of pollination. We also learnt to draw the flower parts in one of the practicals.

Pollination (Methods)

Pollination is the transfer of pollen grains from the anther to the stigma

In Self-pollination; pollen grains are transferred to the stigma of the same flower or a different flower on the same plant, while,

In Cross-pollination, pollen grains are transferred to the stigma of a different flower on a different plant of the same species.

There are advantages and disadvantages to both Self-Pollination and Cross-Pollination.

Advantages of Self-pollination                             Advantages of Cross-pollination

- Only one plant is required                            - Offsprings inherit beneficial traits from one another

- Does not depend heavily on pollinators          - More varieties of offsprings are produced making 

- Less pollen grains and energy is lost                 it more adaptive to environmental changes

- Higher probability of pollination                     - Seeds produced are more viable over a longer

                                                                              period of time

Disadvantages of Self-pollination                          Disadvantages of Cross-pollination

- Offsprings are less adaptive to new                  - 2 parents are required

environmental challenges.                                   - Dependent on pollinators

- Continued self-pollination results in weaker,     - Lower probability of successful pollination

smaller offsprings that are less resistant to         - More energy and pollen grains are wasted.

diseases.

Fertilisation and Pollination

Reflections

I did very badly in this term's test as I was not able to fully understand the topic of Acids and Bases. At the same time, I did not memorize all the names and functions of the flower parts in the plant. After reflecting upon this, I found out that I have been over-confident this Term. A drop from A1 to D7 was very depressing, and I regretted not paying close attention to the notes and worksheets provided by the teacher, and left some worksheets undone. Therefore, during the holidays, I made use of my time wisely to thoroughly revise through my notes and worksheets. To further my understanding I bought assessment books for practice. I suddenly felt that the topic on Acids and Bases, which I previously thought was too complicated to comprehend, was much more exciting and interesting than I expected.

I also completed all the practices on Acids and Bases and read through the notes for Biology and managed to memorize all of the facts for sexual reproduction in Plants. I was overwhelmed having found out that I could have done much better if I had been more serious and managed my time more properly.

Nevertheless, this term has taught me an important lesson, and has driven me into looking closer at the mistakes I made previously. My holiday time was used to catch up with the others and I was pleasantly surprised with how I went through the fulfilling holidays.

Additional Websites

Strength of Acids and Bases:
http://chempaths.chemeddl.org/services/chempaths/?q=book/General%20Chemistry%20Textbook/Reactions%20in%20Aqueous%20Solutions/1437/conjugate-acid-base-pairs

Some Experiments(Acids and Bases) made by Online Users:
http://www.funsci.com/fun3_en/acids/acids.htm

Reproductive Processes:
http://ananthacompapp.yolasite.com/reproduction-processes.php

Term 1

The Periodic Table

In this term, we were introduced to the periodic table, which groups elements based on their properties.

We were taught how to derive the number of protons, electrons and neutrons by referring to the periodic table. We also learnt about ions and compounds.

Ionic Bond: result the transfer of electrons from metal atoms to non-metal atoms forming positive and negative ions. The electrical forces between these oppositely charged ions  produce strong ionic bonds.

Covalent Bond: formed by the sharing electrons between two atoms. Each atom contributes 1 electron to the bond.

Figure 1

Atomic Number = No of Protons = No. of electrons

Nucleon/Mass Number = No of protons + No of neutrons

Carbon: 

Atomic Number 6 = No. of protons and electrons

Mass Number 12 = No. of protons + neutrons

Neutrons = 6

Protons = 6

Electrons = 6

Figure 2

Figure 2 (Above) shows the structure of an atom, consisting of the proton, neutron and electron.

Welcome!

Welcome to my Science E-portfolio! I'm Pang Yong Ray from Class 2P3, Register 21.

Scope:
Term 1
Term 2
Term 3
Sabbatical

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