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"But soft, what light through yonder window breaks?"

So, to recap: in a learning setting - a classroom, an agile space, a homework bedroom, a boardroom, coaching space, wherever, you need good light for your brain to work well. Outdoor light is often up in the many thousands of Lux (see below) but indoors you at least need to be over 500 lux. 1,000 lux would be a good target, but 500 will do. Below that learners lose attention, engagement, recall and more. Their behaviour and performance are noticeably worse.

Elsewhere you can read more - see our pages, or this on high refraction paint. Painting the walls and ceilings with bright Lumitec white paint helps, so do light desktops and you need to clear all the paper from your glass windows too.

However, this page concerns the lighting:

Beyond getting the best outside light into your space, and making sure it gets reflected around in there, rather than absorbed, your friend here is LED lighting. It is cheaper to run that the old fluorescent tubes, the light quality is dramtically better, and it is easy to fit - or retro fit - LED bulbs these days. A caveat would be that rooms were historically often underlit - so changing bulbs is good, but adding further light fittings may be necessary too. This is a quick win in terms of cheapness and impact on brains & behaviour.

In short, better light from these bulbs, once you get above 500 lux for everyone, will translate into enhanced cognitive task performance and saves money (and the planet!). See also other issues with fluorescent lighting.

What is the ideal white light?

Not quite as straightforward as you might hope. In simple terms, you are seeking the "coolest" white liight (but caution, see below. The cool or warm description refers to how they look - blue ice is cool, a yellow sunshine is warm. Nothing to do with actual temperature of the bulbs.

Fluorescent tubes are usually under 3,000 Kelvin are much too "warm" / yellow WORST CHOICE

"Warm white" LED is 2,700 - 3,000K and is not much better that tubes STILL POOR CHOICE

"Cool white" LED is around 3,500 - 4,100 K and is STARTING TO BE ADEQUATE

"Natural or daylight" LED is 5,000 - 6,500 K THE THEORETCAL BEST BY FAR

So just a note of caution, the ones they call "Cool white" are not the coolest! Natural or dayligh is what you seek and they ARE the coolest. Some folk find the slightly blue tinge at the 6,500 K end of this a bit off-putting, some like it a lot, but anywhere within this "daylight range" is good.

Here is a typical display of the kind of thing you are seeking (this from Amazon, but other suppliers are available...)

daylight LED specs

Note how cheap the bulbs are- low power, long life - easy to justify given the impact on learning too

strips or spots?

Really look aound your space in planning, and have an intention to leave no dark corners. Spots can be too narrow and you end up with little puddles of good light - the bulbs above have a beam angle of 120° and look out for these wider beams. Sometimes people tell me that they have a group of "naughty" children in a corner of their class, but typically the kids are fine, it's the room that disengages them.

However, in painting all the walls very white and fitting daylight white LEDs it might be argued that it's all a bit anodyne. Again, LEDs come to your rescue. LED strips around the top of your walls can bring variety and interest - seek strips that can do colour change and have controls for that easily reached and labelled. Research suggests that red wakes you up in the mornings (hence red all over BBC breakfast TV) but other colours really just bring variety = interest.

This classroom wall below is indicative - read about that whole class makeover from Juliette Heppell's (free) iBook. The students chose the colour strips, change them during the day, and called them mood lighting.

LED mood lighting

But above all else, get those Lux levels up in every corner of your learning space.

What does the research say?

Three, from very many papers:

"light intensity influences our cognitive performance and how alert we feel, and that these positive effects last until early evening" From Let There Be Light: It's Good for Our Brains, Neuroscience News

"Though participants may not improve memory for verbal or spatial information, their ability to quickly recall information and apply it to a complex cognitive task is greatly improved," Cognition at the speed of light" Association for Psychological Science

"Acute exposure to blue wavelength light during memory consolidation improves verbal memory performance" Waseda University, Japan

And the Great Outdoors...

Memories? Whilst the plural of Anecdote is not Data, many of us share wonderful memories of outdoor learning: that hot summer's day with the class under a tree, learning in Scouts or Guides, play based learning, sport, picnics, forest schools, beachschool... Some of this is because those social markers for learning, the cues and clues that help us to build taxonomies of understanding are strong because outdoor is 'special" and never homogeneous, but also the light levels are wonderful, oxygen is high, CO2 low, temperature better than indoors on a hot day, and more (see of course).

Children in many education systems are currently getting less outdoor learning, rather than more. Self evidently, this is a mistake.

And finally, other issues with fluorescent lighting

Fluorescent tubes / striplights are complex. With each cycle of an alternating current (AC) they produce 2 "flashes" of ultraviolet light which is converted to visible light by a phospor coating inside the bulb. Both the flicker and the colour variation between each flicker happen very rapidly, but we know that the eye responds - it os subconscouly distracting. For some children, reading is easier and quicker with a colour overlay on their readng material - but this is actually responding to the problems with the lighting, not problems with the child! One suggestion is that the coloured overlay makes the rapid colour changes less dramatic. See this note for example.

Although today's newer Fluorescent tubes are better, many classrooms still have the older (long lasting!) bad bulbs. An additional impact is found on health: stress, headaches, migraines, eye strain and tiredness.

So the better LED lighting, with high Kelvin value, low running cost, and brighter bulbs, improve learning, reduce the damage to reading, leave teachers and children feeling a lot better, improve behaviour significantly with attention and concentration up too.


page first created by professor stephen heppell, initially for pals at brightlingsea sailing club - last updated Monday, January 6, 2020 2:27 PM