Physics games red and blue

On the diagram at top right, the proportional response of the 'red', 'green' and 'blue' photoreceptors is shown as a function of wavelength. A three-colour representation of a spectrum is shown below the graph. Suppose that light from the yellow region of the spectrum, with a wavelength of say nm, arrives at the retina. It lies between that of red say nm and green nm , so this light stimulates both red and green photoreceptors.

This evokes a sensation that we are taught to call yellow. However, yellow that you see on the monitor is not light with wavelength near nm. Instead, the monitor makes yellow colour using red light and green light from the same pixel.

These two different wavelengths from the monitor are focussed onto a small area on your fovea, where it also stimulates red and green photoreceptors. So we perceive the effect as similar to light with wavelength nm, even though no light of this wavelength is present. We can't show you the difference, because you are probably looking at a RGB screen and it can only show you light with three wavelengths.

No matter what we do, we can't get it to produce nm! Many species of insects and birds have four-colour vision, often with sensitivity to near ultraviolet light. Some flowers have petals that are patterned in the UV but which appear homogeneous to us. A four colour vision system Additive colour mixing by projection Let's look at other ways of adding colours. In this movie, we use three slide projectors, with red, green and blue filters. We vary the intensity in each successively.

Depending on your screen, your eyes and your vocabulary, you'll probably see that, once again, red plus green light makes yellow, green plus blue light makes cyan, blue plus red light makes magenta. One way of combining colours, without a computer monitor, is to illuminate a rotating wheel whose sectors are painted in different colours.

The eye integrates light over a few tens of milliseconds, so in that sense it adds the colours that are successively presented at a given point on the retina. We demonstrate that here, using a drill to rotate the wheel. Here, the combination of colours cannot be brighter than the average of all of the colours so, on the monitor, it appears grey rather than white.

Of course, if we compare grey in bright light and white in dim light we may not see a difference. We all remember our first set of paints: red paint plus green paint do not make yellow! Yes, there's a big difference: with paints we are not adding light, but subtracting it. White paper reflects all colours; when we add coloured paint to it, that paint allows some colours to pass through, but absorbs subtracts others. Just as most colours can be made by mixing light with proportions of the three additive primaries, we can also produce most colours by starting with white light and subtracting different proportions of three subtractive primaries:.

The subtractive primaries are these: Magenta passes red and blue: it absorbs green light Cyan passes green and blue: it absorbs red light Yellow passes red and green: it absorbs blue light We hope you've noticed that the subtractive primaries are the complementary colours of the additive primaries.

In practice, you are probably reading this on an RGB monitor, then the white really is made from an RGB pixel combination. Subtractive mixing: e. However, this is not really subtractive mixing: if you are reading this on a monitor, then all the colours and white are made from different proportions of red, green and blue. If you want to see real subtractive mixing, you could print it out. Your printer will start with white paper and then print a mixture of cyan, yellow, magenta and black pigments.

A very popular and peaceful Physics Game is Falling Sand. It is a cool particle simulation game about nature and how it works. Let seeds fall into the sand, water from the sky and life will start to grow on Earth. Do you want to have some more responsilbility? Then try playing Bridge Builder, a free construction game where you have to build bridges.

In this online bridge building simulator you get to try your hand at being an architect. Use your tight budget to plan a bridge that is safe and stable enough to allow a fully loaded truck to pass over it.

Amigo Pancho. Amigo Pancho 2. Ball in the Hole. Boat and Friends. Bubble Quod 2. Cake Connect. Cannon Basketball 4. Can You Even. Car Drawing Physics. Catch the Candy. Chromatic Seals. Couch Cover Orange Journey Knights. Cover Orange Journey Pirates. Crumbling Construction. Cute Elements. Dead Sticks. Destroy the Village. Doctor Acorn 2. Domino Simulator. Donutosaur 2.