The following Topics and Sub-Topics are covered in this chapter and are available on MSVgo:
Light, shadows and reflection is a class 6th NCERT science chapter that introduces you to the world of light and its properties. Surprisingly, both mirrors and reflections are formed from light, but this happens due to their different properties. You must have seen that rainbows form after the rain- this phenomenon is due to reflection.
Light is a kind of electromagnetic radiation that can be detected by our naked eyes. Light is constituted of a bundle of rays that run in any one particular direction on a straight path. The speed of light has been calculated to be around 3 * 10^8 m/s. That’s tremendous speed, and due to this speed, property light can travel from the Sun to Earth in just 500 seconds. If you have a machine that can go with light speed, you will be in the sun until you complete one of our lesson video tutorials. That’s fantastic, isn’t it?
All objects around us cannot produce light. Let’s see how we can categorise items based on this.
It’s a basic property of light that any ray of light travels in a straight direction. It cannot be bent without applying any external force. Hence we get the angles of incidence equal to the angle of reflection in the reflection topic.
Transparent, Opaque, and Translucent Objects
We can have different types of objects that behave differently when encountered with the light source. Let’s see their types below:
Reflection is a natural physics phenomenon in which the light bounces back from the reflecting surface and changes its direction.
When you drop the ball on the floor, it bounces back. Why doesn’t it pass through the ground? This is because the floor acts as a medium of change of momentum for the ball. In optics, we can say this medium acts as a reflecting surface.
Hence, whenever a ray of light strikes a reflecting surface, there is the direction’s reversion, although the intensity remains the same if there is no external force and pressure on the ray of light. The momentum is conserved when the directions are reversed. We have a property in reflection as follows:
Lights and shadows are very interesting phenomena in physics. Apart from them, we even have a reflection and refraction phenomenon. In submarines, we can see the surface through a device called a periscope. It uses the dual reflection method to get the view of levels different from viewers. The spectacles that we wear also use the properties of refraction to show you clear and distinct images. We can even make a pinhole camera using light properties. There are a lot of widely used optical instruments that help us in our daily lives.
Shadows are the projections of blocked lights on any surface. At the same time, reflections are the lights being reflected when hitting any surface and forming an image on the surface.
Reflection is a natural phenomenon where the light hits a reflecting surface and bounces back in proportion to the angle of incidence. When you stand in front of the mirror, your image is reflected, and hence you can see your beautiful face.
The shadows can be divided into three parts based on the source of light. These are umbra, penumbra, and antumbra.
Shadows are formed in the presence of light. When the light is blocked from any object, then a shadow is cast. Hence we can see shadows in the presence of light. For example, in the daytime, you find the leaves’ shadows under the tree.
No shadows are not a reflection as there are different ways the light is treated in both. In shadows, light is blocked, whereas, in reflection, the lights are bounced back.
Shadows are dark shaped images formed on a surface when light is blocked from any solid object.
You can find detailed video explanations for the topic reflection and shadows from MSVgo, and learn using intuitive videos. The videos will also explain how refraction is found in spectacles and other such relatable objects.