Optics, one of the most interesting areas of study in classical physics, allows us to fully visualise the behaviour of light and colours, It is for this reason that any kind of experiment that facilitates the study of optics is welcome. Today, we will look at how to make a Newton disc quickly and in a didactic way.
- A damaged disc (CD or DVD).
Assembling our Newton disc
The first thing we are going to do is to draw Newton's disc on the paper, adapting it to the size of our CD or DVD, then we cut it out and with the help of a ruler, we divide the disc into 7 parts that we will paint with the following colours: red, orange, yellow, black, light blue, navy blue and brown.
If we have a printer, we can copy an image of the Newton disc, burn it to our PC and print it out, then proceed to cut out the Newton disc and it will be ready to stick on the CD or DVD.
Once we have the Newton disc ready, we stick it to the CD or DVD with the help of glue, avoiding that air is trapped inside the paper where we have made the Newton disc, the idea is to have a completely smooth surface with the colours on one side of the disc.
With the structure done, it is time to spin the disc to observe the optical effect. To do this, we place a marble in the centre of the CD until it fits and we spin it quickly, we will see that the colours will form a single white colour that we can see while the CD is spinning. Newton's disc.
How it works
One of Isaac Newton's most interesting discoveries was to observe how sunlight was broken down when it passed through a prism. By observing this phenomenon, he intuited that the reverse effect could be created by making the colours form a white light.
The mechanism is basic, but efficient. When the disc rotates, it does so at a much higher speed, at which the eye cannot distinguish the colours separately. Thus, the human eye begins to mix the colours in order to give information to the brain about what is happening, which is why we see only one colour: white.