Vision

EYES AND THE BRAIN
Come see the world around you in a different light! Find out what happens in the eyes and brain as we see and learn what it means to be colour blind. Discover how new light technology can help us feel more awake and learn how other animals view the world. Come and get a flavour of the world of vision and different colours in our ‘Now You See Me’ Vision zone!

Fun activities:
Find out if you see the same colours as your family and friends….can you tell red from green? ● Take a glimpse at the television of the future, and mix lights and paints, to understand how your brain can be tricked into not seeing what’s right in front of your eyes! ● Discover how some other animals see the world: Find out how what your dog sees whilst watching TV, and have a go at painting a picture whilst seeing the world like your pet! ● Test live flies to see if they’re blind! See the world through tiny fly lenses.

 

Discovery zone 1: The Colourful World of John Dalton

Do you see the world around you in the same colours as your friends? Is there a reason your brother tries to mix clashing colours in his clothes? The way we see can be different due to genes that we inherit from our parents.

Humans have different types of cells embedded in our retina at the back of the eye that detect light, called photoreceptors. One type of photoreceptor called a rod is specialised for picking out small amounts of light in the dark, while a second type comes in three flavours, with each specialised to pick out a different part of the spectrum of light. These are called cone photoreceptors and it is these that can be different in some people, detecting a different part of the spectrum.

The spectrum of light reflected from a banana or an orange.

The spectrum of light reflected from a banana or an orange.

The differences that some people have in these cone cells were first described by a Mancunian called John Dalton [LINK], who was himself colour blind! John Dalton became an important scientist also involved in chemistry. This very year 2016 is the 250th anniversary of his birth. Come and find out more and have a go at picking out these colours yourself at our colourful stand.

Discovery Zone 2: Tomorrow’s TV

Have you ever been disappointed when you take a picture on your camera? Wondered why it doesn’t look like what is right in front of your eyes – the colours aren’t quite the same, or the patterns in light and shade are a little flat?

This is because the eye contains a mosaic of cells that detect how BRIGHT the world is. These melanopsin cells are what tell your brain whether the Manchester sky is grey and overcast or full of bright sunshine, and even what time of day it is!

Brightness detectors form a grid in your eye, just like pixels in a camera! A melanopsin cell (left) catches the light with its spiny arms, like a fishing net. All melanopsin cells send their information to the optic nerve in the centre of the retina (right).

Brightness detectors form a grid in your eye, just like pixels in a camera! A melanopsin cell (left) catches the light with its spiny arms, like a fishing net. All melanopsin cells send their information to the optic nerve in the centre of the retina (right).

By looking at our TV of the future, you can understand how a picture we take on our camera recreates the world around us – and how our eye does things in a similar, but in a much cleverer way, by using melanopsin to help judge how bright the world is! By mixing different coloured lights, just like mixing paints, you can learn how you can trick your eye into seeing things in a completely different way. Find out how your brain can be tricked into NOT seeing things that are right in front of your eye!

Discovery zone 3: What is your dog watching on TV?
So how do other animals see? Mammals in general actually have pretty rubbish visual systems. Reptiles and birds, on the other hand, can see more colours than we can as they have more cone photoreceptor types. We probably lost some of these when mammals became nocturnal at the time of the dinosaurs.

So what do our canine companions see on the TV whilst they’re sat beside you on the sofa? Because your dog’s eye contains fewer types of cone photoreceptor cells than yours, they see patterns in colour and brightness in a different way. To learn more about this, come to try on our pet-specs, and see the world as your favourite animal! By doing this, you can learn more about how your own eye sees patterns in colour, light and shade, and how this is all down to the tiny cone cells found in your eye! Have a go at painting a picture whilst wearing your pet specs, and discover how animals see the world in a completely different way to you!

Discovery Zone 4: A Creepy Crawly Vision

ComicFly

Can flies see better than us?

It turns out a lot of insects can see better than us as well. Their eyes are made up of many tiny units each with their own lens…..this means they can process some information more quickly than we can (ever tried swatting a fly? They always win!). Many insects can also detect ultraviolet (UV) light very well, while we can only see this when it has blue/violet light mixed in. In our insect vision zone, come and test whether the genetically modified flies we have can see, and if they can see UV. Find out how humans can use information like this to help us in biotechnology and pest control! To learn more about comparing organs of human and fly, read here.

Human and fly photoreceptors detect light in different parts of the spectrum.

Human and fly photoreceptors detect light in different parts of the spectrum.

Contributing research groups:

  • Helena Bailes, Univ. of Manchester — [LINK]
  • David Foster & Kinjiro Amano, Univ. of Manchester — [LINK]
  • Rob Lucas & Annette Allen, Univ. of Manchester — [LINK]
  • Frank Mair, Univ. of Manchester — [LINK]
  • The Manchester Fly Facility, Univ. of Manchester — [LINK]