Download Print Activity - Let`s Talk Science

How can I tell which way is north
at night?
Make a constellation viewer and learn about the North Star.
Setting: Outdoors (on a clear night)
Time: < 30 minutes
Concepts: stars, constellations
Skills: observing
Subject(s):
 Astronomy & Space
Ages:
 6-8
 9-11
Materials:
• Image of the Big Dipper and Little Dipper constellations (see below)
• 14 glow-in-the-dark stickers (stars or dots) (optional)
• Flashlight with red cellophane covering the light end (optional)
What to do!
1. Print out a copy of the Big Dipper and Little Dipper image below.
2. Stick glow-in-the-dark stickers (stars or dots would be best) over the stars of the Big
Dipper and the Little Dipper. Use larger stickers for the North Star (Polaris) and the
Pointer Stars (See diagram – these are stars that point to the North Star).
3. Just before you go outside, hold the image with the glow-in-the-dark stickers under a
strong light source for several minutes.
4. If you don’t have access to glow-in-the-dark stickers, you can cover the end of a
flashlight with red cellophane and shine this on the image when you’re outside (this way
you can look at the image and the night sky without losing your ‘night vision’).
5. Go outside to a dark area where you have a clear view of the night sky above you.
Locate the Big Dipper (Ursa Major); it looks like a big pot in the night sky.
6. Once you have located the Big Dipper, find the two ‘Pointer Stars’ on the end of the ‘pot’
portion of the Big Dipper. Imagine a line that extends up past the Pointer Stars that is
five times as long as the distance between the Pointer Stars. You will find a star at the
end of that line, which is at the end of a constellation that looks like a smaller version of
the Big Dipper.
7. You’ve found the North Star! If you face towards the North Star, you will be facing north.
What’s happening?
A constellation is a group of stars in the sky that form a fixed pattern in relation to each other, as
viewed from the Earth. Astronomers currently recognize 88 constellations in the Northern and
Southern hemispheres. Our modern constellation system comes to us from the ancient Greeks.
No one is sure exactly where, when or by whom this system was invented. The constellations
are believed to be totally imaginary things that poets, farmers and astronomers have made up
over the past 6 000 years.
The Little Dipper (Ursa Minor, The Little Bear) is a special constellation because the last star on
the handle is the North Star (Polaris).
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How can I tell which way is north
at night?
Photo: Picture showing the location of Polaris in relation to the Big and Little Dipper. Adapted
from http://upload.wikimedia.org/wikipedia/commons/f/f5/Finding_polaris.png
Why does it matter?
The North Star is important not because of its brightness, but because it is the only star that
never appears to change its place in the sky. Even while the other stars and constellations are
moving, Polaris stays put! If you are in the northern hemisphere, you can always tell which way
is north if you find can find the North Star.
Investigate further!
The North Star is not visible in the Southern Hemisphere. Is there a star that is the equivalent of
the North Star in the Southern Hemisphere?
2
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