Solar Bottle Lights
What do you think houses are
like in rural Uganda?
• Many houses are built using mud and
have thick thatch roofs.
• They also have very few windows, so
are often very dark.
Watch the Video
• What happens when the bottles are put
through the ceiling?
• https://vimeo.com/34607729
Time to Make your own
Solar Bottle Light
Testing Your Solar Bottle Light
• Take the Solar Bottle Light out of the box and cover
the hole in the top, how much light is there in the
box?
• Uncover the hole in the top, how much light is there
now?
• Put the Solar Bottle Light back through the hole, how
much light is there now?
What is happening?
• The process is called light refraction.
• Light refraction occurs when light passes from one
material to another i.e. when light travels from air to
water.
• When a light wave moves from one material to another
(i.e. air to water) it slows down.
• This causes the light to change direction i.e. rather than
travelling straight down through the water, it travels
diagonally.
• This means that when we look at things below the
water they are distorted (they appear differently to
how they really look).
• Look at how the straw below appears to be in two
pieces.
So, why does the Solar Bottle Light
increase the amount of light that comes into
the room?
Draw a diagram of the Solar Bottle Light to
show what happens to the light waves when
they go through the water. Draw 3 light waves
going down through the bottles and into the
box.
Light source
• If you only had a hole in the roof then the
light waves would go straight down
However, because the light waves are
travelling through air and then water,
they are travelling diagonally into the
room.
• This means the light waves spread out
and allow more light to enter the room.
The original Solar Bottle Light was invented
by Alfredo Moser in Brazil
To learn more about his invention, watch
the video: http://youtu.be/owsZxIVc9DE
Find more resources at:
sendacow.org.uk/lessonsfromafrica
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