Reflection on what I have learned in term 2

In term 2, I learned Physics. To be more specific, I learned about reflection, refraction, lenses and colors of light. To start off, in the topic of reflection, I learned about the angle of incidence, the angle of reflection and the normal. If a light ray hits the mirror, the angle that is perpendicular to the mirror is called the normal. The degree between from where the light ray came from to the mirror is the angle of incidence. The degree between the reflected ray and the mirror is the angle of reflection. Also, the angle of incidence and the angle of reflection is always the same.

Moving on, some things that I learned about refraction is the total internal reflection, the critical angle and how refraction occurs. Refraction is changing the path of the light ray when it passes through an object. However, refraction will not occur if the light ray enters the object perpendicular to it. Total internal reflection is the light ray reflecting within the object when it passes through the object and hits a flat surface of the object. Total internal reflection only occurs when the angle of incidence is larger than the critical angle. If the angle of incidence is exactly the same as the critical angle, the light ray will follow the side of the object and exit the object.

Next, about lenses, I learned about how the path the light changes when it hit a lens. I also learned about the different terms, for example, the focal point, focal plane, principal axis, optical center and the focal length. There are also many different scenarios of how the path of light changes when it hit the lens in different ways. For example, if the object stands on the focal point, and the light rays come from the object, the light rays will hit the lens and become parallel, making the image have an infinity distance. However, if the object is very far away, and produces parallel light rays, when it hits the lens, the image will converge below the focal point, on the focal length.

Lastly, the last thing that I learned during term 2 about science, is colors of light. The prism is able to split the white light into different colors of light. When the white light is split into different colors, the band of light created is called the visible spectrum. We call the process of the light splitting, dispersion of light. Also, different objects reflect different colors of light. For example, an apple reflects only red light and absorbs the rest of the colors, therefore it appears to be red. Black colored objects absorb all the light, therefore it appears black. If, blue light was shined on an apple, it will appear black, because it will absorb all the blue light. However, if magenta (blue+red=magenta) light was shined on a cyan(cyan=blue+green) object, the object will appear blue, because, it will only reflect blue light.

That is all for what I had learned in term 2.