FISICA GENERALE
INGEGNERIA EDILE-ARCHITETTURA
Brief history of lighting (1)
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400.000 years B.C Flaming torch invented (kindling)
13.000 years B.C
Animal / vegetable lamps
5.000 years B.C
Vegetable / fish oil lamps
400 years B.C
Candle invented
Brief history of lighting (2) 1790 s 1890 s
•  1792 First gas lamp: William Murdoch heats coal to
produce gas to light his home and office in Redruth,
Cornwall
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1801 Sir Humpry Davy invents electric carbon arc
lamp
1814 First general use of gas street lighting in
London
1874 Incandescent bulb invented by Joseph Swan
and Thomas Edison
1880 First premises lit with Swan lamp in Cragside
(Newcastle)
Brief history of lighting (3) 1900 - 1930
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1901 Mercury vapour lamp patented by Peter Cooper
Hewitt, USA
1907 Tungsten filament lamp introduced by William
Coolidge, USA.
1901 Red neon tubes made by George Claude in France
1925 Blue tubes (Argon + Mercury) produce and used in
London
1927 Fluorescent lamp patented in Germany
1932 Low-pressure sodium lamps introduced for street
lighting in London and in The Netherlands
1937
First fluorescent lamps shown in New York
Brief history of lighting (4) 1950 - 2000
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1957 Quarz halogen lamp patented by General Electric
1965 Red Light-EmittingDevice (LED) developed
1968 Green LED developed
1971 Amber LED developed
1980 Compact Fluorescent lamp with integral ballast
developed
1992 Blue LED developed
1992 White LED developed
200x OLED lighting demonstrated
Conclusions - lighting
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1st 400k years
Light created by combustion of
carbon based materials
Last 200 years
to create light
Heated wires in evacuated glass bulbs
Last 100 years
Electricity excited gas plasmas by
direct/indirect heating to emit light (neon tubes,
fluorescent tubes, compact flurescent lamps)
Last 50 years
Development of Solid State materials
that emit light when excited by electricity (LEDs)
Timeline della invenzione
delle sorgenti luminose
toria
00 a.C.
oggi
20.000 a.C.
2000 d
oggi
Dobbiamo lasciare
perdere la candela?
Free ebooks
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etics, and space exploration, many of which can be used to generate an interest in scien
ng students. However, it is often the case that the most simple and traditional of scienc
nomena are the most effective at teaching students to use science process skills and gain
ntific content knowledge. Michael Faraday chose one such simple phenomenon, the che
ory of a candle as the theme for a series of lectures he gave at the Royal Society in 1860
se lectures have become a classic example of how scientific principles and ideas can be
uced through the use of simple practical work and reasoning.
How Do Candles Work?
What Does a Candle Produce When It Is Burning?
What Does a Candle Need If It Is To Keep Burning?
How Does the Wax Get to the Flame?
Why Do Candle Flames Burn Brightly?
Comparing light sources to real life
Colour temperature
Kelvin
Blue sky
Uniform overcast sky
Average natural daylight
High pressure mercury cool white lamp
Fluorescent warm white
Halogen filament lamp
Tungsten filament
High pressure sodium lamp
10.000
7.000
6.500
4.000
3.000
3.000
2.700
2.050
Some typical lamp efficiencies today
Type of lamp
Lumens per Watt
Ideal white light
100 W tungsten incandescent
40 W tungsten incandescent
Quartz halogen
36 W fluorescent tube T8
28 W fluorescent tube T5
Low pressure sodium lamp
Xenon arc lamp
White LED
250
175
126
24
up to 93
104
up to 200
50
25-70
Type of lamp
Lumens per Watt
Total lumens
+ rest of energy as hea
Ideal white light
250
250
0W
W tungsten incandescent
17,5
1.750
93 W
W tungsten incandescent
126
504
38 W
50 W Quartz halogen
24
1.200
45 W
6 W fluorescent tube T8
up to 93
3.348
23 W
8 W fluorescent tube T5
104
2.912
16 W
White LED
25-70
25-70
0.90 - 0.72 efficacy
White LED (in lab)
100
100
0.60 efficacy
Altri fattori da considerare
•  Durata nel tempo della sorgente luminosa
•  Costo!
•  Impatto ambientale della produzione/
smaltimento
•  Estetica
Conclusions - lighting
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1st 40k years
Light created by combustion of carbon based materials
Last 200 years
Heated wires in evacuated glass bulbs to create light
Last 100 years
Electricity excited gas plasmas by direct/indirect heating
to emit light (neon tubes, fluorescent tubes, compact flurescent lamps)
Last 50 years
Development of Solid State materials that emit light when
excited by electricity (LEDs)
Last 5 years
(OLED)
Demonstrated printable organic light emitting materials
Emerging technologies take 10-15 years from invention to
first commercial exploitation
For any meaningful commercial impact in the marketplace
by 2020, the technology must already exist in the laboratory
“scientific citizen”
cittadino munito del sapere necessario per poter comprende
valutare responsabilmente la grande dimensione nella qua
viamo.
oi viviamo in due dimensioni completamente nuove che sono
obale e l'innovazione scientifica e tecnologica.
e e due queste dimensioni devono essere riportate alla misura democratica, che sign
acità innovativa, culturalmente. Per esempio alcuni paesi paesi si sono dotati di com
, che sono interlocutori dei cittadini. Questi comitati etici si preoccupano di fornire bu
rmazione, selezionare l'informazione scientifica, proporre le alternative possibili, avviare
ogo all'interno dell'organizzazione sociale, perché potrebbe succedere che: "voi citta
fabeti in queste materie non avete diritto di voto, anzi, dovete fare una sorta di obiezi
oscienza al voto in queste materie".
al'è il senso profondo di questa argomentazione? C'è il pericolo che qualcosa, nel mon
sa essere sottratto a quella che si chiama la sovranità popolare. "Voi cittadini non a
e in questa materia", "non andate a votare perché non siete capaci di votare".