Reflection of my growth development in Science

Science has really benefitted me through these years, and that it had developed an interest into me. This year, we have learnt on various topics, such as chemistry-atom structure,reactions , physic-reflection and refraction,colours of light, lenses, and biology-ecology,sexual reproduction.

It was fairly easy to learn these topics , although I still faced various difficulties at the start. When we first started on these topics, many questions were in my head. Like, why did that happen? how does it happen? However, this was quickly resolved as I had asked our teacher, and also conducted my own research. The hardest topic I found was reflection and refraction. This was because at the start, I did not grasp the concept, and had to inquire a lot about it to understand the reason behind it. However, after that, it was fairly simple to understand the other related topics on colours of light and lenses.

Other than that, biology was a new topic that we were taught on. Ecology was fairly simple, but there was a lot of information to learn about. Therefore, I feel that my progress is still decent, and that my growth development in science is still ok.

Term test reuslts and reflection

This term, I did quite well for my science and have managed to acheive an A1 for science. The topics tested were colours of light, lenses, and ecology. This was fairly easy once I understood the concept, and after revising, the test was managable to complete. I have learnt a lot about these topics, and am very interested after it was taught. I also conducted my own research on such topics to understand further about it. However, I should not take science as a simple subject and be arrogant about it, and that I would definately continue this good progress. My goal now is to maintain this A1 result in EOY, and my progress would be to start my revision now, during the September holiday.

Colours of light-Wavelength

When light travels through a prism, it would disperse into the different colours of light. Red, orange, yellow, green, blue, indigo, violet. The white light would disperse into a visible spectrum of light, containing the colours of the rainbow. This is because of the refraction of the lights. The lights are refracted at different angles, resulting in the spectrum.

This made me wonder, why would it be refracted at different angles?

This is due to the different wavelengths. As red has a greater wavelength of 700mm, it would travel faster than the other colours, and thus be refracted least. While indigo has a wavelength of 400mm, it travels the slowest, and thus be refracted more. This would result in the dispersion of light. As light passes the different mediums of air to glass, the reduce in speed causes refraction. At different speeds, the different colour lights would be refracted at different angles, resulting in a visible spectrum.

Dispersion of white light

Different wavelengths resulting in the angle of refraction

Application of TIR-total internal reflection

Through our science lessons, we got to learn about refraction and total internal reflection, which takes place because 1)the incident angle is greater than critical angle 2)the incident ray is in the optically denser medium.

The critical angle is the incident angle whereby the angle of refraction is 90 degrees

After learning this, I conducted an ACE assignment on the application of total internal reflection.

1)Optical fibres

Optical fibres make use of TIR to trasmit data from one end to the other.  It is made of pure glass, and transmits light from one end to the other through TIR within the fibre. Therefore, it would have the advantage of no electromagnetic interference, and therefore lesser loss of signal. It is also thin and flexible.

2)Medical equipment

Such equipment are like endoscope, colonoscope, otoscope and amnioscope. These equipment make use of TIR examine the internal organs in our body.For example, in the endoscope, it is used to examine the lungs. Hence, light is required to see. Light is transmitted through optical fibres, which provide the light source and enables the doctor to examine the lungs.

Contruction Ray Diagrams

How to construct a ray diagram on a plane mirror.

This is a sum-up of how to do so:

1)Locate the image point. One of the image property of a plane mirror is that the distance between the image and the mirror is equal to the distance between the object and the mirror. Therefore, we would be able to locate the image point.

2)Draw a light ray from the eye to the image. When we look into a mirror, we would see the image. Therefore, we can draw a straight line from our eye to the image point.(Use dotted lines behind the mirror)

3)Draw a line from the object to the mirror point where the light ray had intercepted.

This is a simple way of constructing a ray diagram.

Reflection and Refraction

This topic was rather tough at first, as I did not understand the reason for it, and how to constrcut the diagrams. However, after the first week of lessons, I managed to understand, and was more interested in this topic. To learn this topic, we went through lessons and experiments. The experiments really benefitted us as we got to understand reflection and refraction through activities, which really allowed us to understand better.

Reflection
-All surfaces reflect light
-Definitions

Normal:An imaginary line perpendicular to surface
Incident ray:Ray sriking surface of plane
Reflected ray:Ray reflected of surface of plane

-Rules of reflection
1st rule: The incident ray, normal and reflected ray all lies on the same plane
2nd rule:Angle of incidence=Angle of reflection

-Characteristics of a image formed on a plane mirror
Upright,Virtual,Same size as object, laterally inverted, same distance as object

A virtual image is one that cannot be formed on a screen as actual light rays does not meet at the image point. Instead, the light rays diverge to form the vitual image.

A real image is one that can form on a screen as actual light rays meet at image point.

Chemical bonding

In Sec 2, we have learnt about 2 different forms of chemical bonding. These are ionic bonding and covalent bonding.

Ionic Bonding

Ionic bonding takes place between two or more elements whereby electrons are transferred from one atom to another. This would form ions, and an ionic compound. This takes place between metal and non-metal elements. Examples of ionic compounds are NaCl-Sodium Chloride, CaCl2-Calcium Chloride.

Convalent Bonding

Covalent bonding takes place between metal to metal, or non-metal to non-metal elements. It is a process whereby the electrons are shared between the two elements. For example, Oxygen has an electron configuration of 2.6 . Therefore, it requires 2 more electrons to complete its valence shell and be a stable atom. As such, an oxygen atom would share two electrons with another oxygen atom, and would form the oxygen molecule, O2. Other examples are H2-Hydrogen molecule and H2O-water