wwwmoonshadowmixcoza wwweclipseafricaorg Claire Flanagan claireflan55gmailcom 2016 You need a light that has a shape eg the Sun in eclipse a pinhole make one in a sheet of paper ID: 553796
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Slide1
Pinhole Projection
www.moonshadowmix.co.za
www.eclipseafrica.org
Claire Flanagan claireflan55@gmail.com 2016Slide2
You need:
a light that has a shape e.g. the Sun in eclipse
a pinhole – make one in a sheet of paper
using a sharp pencil
a screen – another sheet of paperSlide3
How it Works
remember: light travels in straight linesSlide4
The Sun is a disk of light for us on EarthSlide5
. . . sunlight shines in straight lines, in all directionsSlide6
But if we limit the lightwith a pinhole
we see something interesting . . .. . . the shape of the Sun!
. . . sunlight shines in straight lines, in all directionsSlide7
paperSlide8
hole
(any shape)Slide9
hole
SunSlide10
hole
Sun
another paperSlide11
hole
sunlightSlide12
sunlight
limited by hole
holeSlide13
patch of light
same shape as hole
holeSlide14
If we make the hole smallerthen
no matter what the shape of the holewe see the shape of the SunWatch
the green rays from one edge of the Sun andthe red rays
from the other edgeSlide15
big hole -> light spreads -> we see shape of hole
holeSlide16
hole
smaller hole -> light spreads lessSlide17
hole
image of the Sun
small hole -> light from edge of the Sun is focused
-> we see shape of SunSlide18
hole
image of the Sun
smaller hole = better focus (but less light = dimmer image)Slide19
big square
big triangle
small square
small triangle
Experiment with different
shapes and sizes of holesSlide20
big square
big triangle
small square
small triangleSlide21
Experiment with
different sizes of holes
bigger
smallerSlide22
bigger
smaller
better focus
brighterSlide23
What if the pinhole is
further from the screen?
pinhole
screenSlide24
If the screen is further,
the image is biggerSlide25
The best pinhole
projecters
aregaps between the leaves of treesSlide26
Put a sheet of paper on the ground
to see images of the SunSlide27
Taller trees give bigger images of the SunSlide28
Photo:
Simon Fishley
Pinhole-projected eclipse under a tree, Cape Town 2009Slide29
Write your name in pinholes, and photograph the projection
Photo:
Astronomical Society of Southern AfricaSlide30
Make pinhole gaps
between your fingers . . .
Photo: Windell Oskay from Sunnyvale, CA, USA Slide31
. . . and watch the eclipse!
Photo:
Windell Oskay from Sunnyvale, CA, USA Slide32
Next solar eclipses for SA . . .
Thu 1 Sep 2016
mid-morning
Sun 26 Feb 2017
late afternoon
Jhb
Cape Town
www.moonshadowmix.co.za
www.eclipseafrica.org