Let There Be Light | National Geographic

the other factor in creating a

the other factor in creating a long-lasting light that doesn’t burn up

long-lasting light that doesn’t burn up

long-lasting light that doesn’t burn up is the glass bulb and Paul Doherty of

is the glass bulb and Paul Doherty of

is the glass bulb and Paul Doherty of the Exploratorium can prove it this is a

the Exploratorium can prove it this is a

the Exploratorium can prove it this is a replica of a bulb from 1900 and it uses

replica of a bulb from 1900 and it uses

replica of a bulb from 1900 and it uses a carbon filament now when you put

a carbon filament now when you put

a carbon filament now when you put electricity through the carbon it glows

electricity through the carbon it glows

electricity through the carbon it glows incandescent makes light but it doesn’t

incandescent makes light but it doesn’t

incandescent makes light but it doesn’t melt and that’s the key incandescence is

melt and that’s the key incandescence is

melt and that’s the key incandescence is the emission of light from something hot

the emission of light from something hot

the emission of light from something hot carbon and tungsten have the strongest

carbon and tungsten have the strongest

carbon and tungsten have the strongest heat resistance of all elements most

heat resistance of all elements most

heat resistance of all elements most modern bulbs use tungsten filaments

modern bulbs use tungsten filaments

modern bulbs use tungsten filaments because it temperatures over 1800

because it temperatures over 1800

because it temperatures over 1800 degrees they are much more durable

what’s the role of the bulb

what’s the role of the bulb these lights all have this case around

these lights all have this case around

these lights all have this case around them and that case the bulb protects the

them and that case the bulb protects the

them and that case the bulb protects the hot filament from the oxygen in the air

hot filament from the oxygen in the air

hot filament from the oxygen in the air creating an oxygen free zone within the

creating an oxygen free zone within the

creating an oxygen free zone within the bulb is the key to incandescent light

bulb is the key to incandescent light

bulb is the key to incandescent light this is what’s inside

this is what’s inside

this is what’s inside it’s the filament we saw in the clear

it’s the filament we saw in the clear

it’s the filament we saw in the clear glass bulb earlier and when I put

glass bulb earlier and when I put

glass bulb earlier and when I put electric current through it and it heats

electric current through it and it heats

electric current through it and it heats up the oxygen in the air will burn it so

up the oxygen in the air will burn it so

up the oxygen in the air will burn it so here it goes so I’m going to heat up the

here it goes so I’m going to heat up the

here it goes so I’m going to heat up the filament and as it gets hot enough it

filament and as it gets hot enough it

filament and as it gets hot enough it will begin to burn in the air

to make bulbs glass has to be extracted

to make bulbs glass has to be extracted from sand here in the Simplot sand pits

from sand here in the Simplot sand pits

from sand here in the Simplot sand pits of southern nevada they mine over 1

of southern nevada they mine over 1

of southern nevada they mine over 1 million tons a year sand is the

million tons a year sand is the

million tons a year sand is the technical term used to describe rock

technical term used to describe rock

technical term used to describe rock which has been pulverized by the ocean

which has been pulverized by the ocean

which has been pulverized by the ocean or other types of erosion this cocktail

or other types of erosion this cocktail

or other types of erosion this cocktail of tiny grains is around 76% silica 4%

of tiny grains is around 76% silica 4%

of tiny grains is around 76% silica 4% clay and 20% other impurities it’s the

clay and 20% other impurities it’s the

clay and 20% other impurities it’s the silica that’s needed to make clear glass

silica that’s needed to make clear glass

silica that’s needed to make clear glass for flashlight bottles in nature

for flashlight bottles in nature

for flashlight bottles in nature translucent silica is seen in quartz

translucent silica is seen in quartz

translucent silica is seen in quartz crystals but turning pulverized quartz

crystals but turning pulverized quartz

crystals but turning pulverized quartz back into something you can see through

back into something you can see through

back into something you can see through is an epic journey

around 26% of this sand will become

around 26% of this sand will become glass

each of these trucks has enough sand to

each of these trucks has enough sand to make 560,000 flashlight bulbs

to make glass sand is mixed with a few

to make glass sand is mixed with a few other key ingredients