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Activity 3 – Make a Star Wheel

Context

The key to becoming an independent stargazer is owning and using a Star Wheel.

Specific Learning Outcomes

You will make a paper Star Wheel for your latitude, longitude and time zone. You will be able to set it to a given time and date, and know how to use it to find stars.

Teacher Planning and Preparation

Introduction

Making a star wheel is not difficult. The whole process makes an excellent science and technology module in a classroom, blending information technology with paper engineering. Access to the Internet is needed to download the designs. They are then transformed into an accurate scientific tool using scissors and sellotape/scotch tape.

A Star Wheel has two parts – a pocket and a wheel. The pocket has a window in it through which you can see the stars.

The illustrations to the right show a Star Wheel for Latitude 55°. The shape of the window will be different for different latitudes. The correct version is automatically selected by our Wheels and Pockets downloads page.

Two Main Stages

Making a Star Wheel involves two main stages:

Stage 1 – Downloading and preparing photocopy masters
Stage 2 – Cutting out and assembling a Star Wheel

Downloading and preparing photocopy masters is simple if you have access to a computer printer that can print on Tabloid or A3 size paper. It is a little more involved if the largest paper you can print on is Letter or A4 size. You should read the instructions (below) before you decide whether to photocopy masters in advance, or whether to get your students to do this as part of the project.

It is recommended that you construct a Star Wheel to use as an example when working with a group.

What You Need

  • Pocket and wheel worksheets (download here)
  • Sellotape/scotch tape
  • Scissors (Ensure you have one pair of scissors per student to allow careful, unhurried cutting out.)
FOR SINGLE-SIDED WHEELS
  • Sheets of plain Letter or A4 size paper
FOR DOUBLE SIDED WHEELS
  • Glue sticks
  • Clothes pegs, bulldog clips, paper clips, or similar
OPTIONAL FOR BOTH SINGLE AND DOUBLE-SIDED
  • Letter files for pocket liner (Use clear L-pocket letter files. These are available from stationery suppliers.)
Depending on your latitude, your Star Wheel will be either single-sided or double-sided. Double-sided wheels involve extra steps in construction. Your Star Wheel will be single-sided if you live north of Latitude 40° North or south of Latitude 40° South. Otherwise it will be double-sided. Our Wheels and Pockets downloads page automatically selects the correct version for you from your city name. You can visit it now to confirm which type you will be making.
wheel
A POCKET

wheel
A WHEEL

wheel
ASSEMBLED AS A STAR WHEEL

Classroom Lead-In

Show students a made-up Star Wheel and name the parts: wheel, pocket, window.

Stress that you are making a machine that will only work well if the cutting is accurate.

You may wish to discuss the geometry of the sky and the star wheel. This engages your students in thinking about the star wheel. See the Science Background Knowledge section of the Star Wheel Home Page.

Instructions

Stage 1 – Downloading and preparing photocopy masters

1.

Visit our Wheels and Pockets downloads page, select your location, and download the appropriate wheel and pocket worksheets. We recommend that you save these files on your hard disk.

The exact process for downloading and saving these files depends on your browser. If you have trouble, visit our downloads help page.

You will notice that there are two choices in wheels: the City wheel and the Milky Way wheels. The City wheel contains a selection of bright stars only – the main constellations and stars that you can see from a medium sized city with reasonably clear air. The Milky Way wheel contains all the stars you might see from a rural location, including an accurate representation of the Milky Way (over 2,000 stars are shown on each side of the wheel). Both the City and Milky Way wheels work in the same pocket.

We recommend that all beginners, including adults, start with the City wheel.

See the Star Wheel Home Page for more detailed background information about the Star Wheel and the different versions.

2.

Prepare Tabloid or A3 size masters

All wheel and pocket worksheets require A3 printing.

If you have a computer printer that can print on Tabloid or A3 size paper, it is simple. Use the Tabloid/A3 format document. You can print on either Tabloid (11 inches x 17 inches) or A3 (297 mm x 420 mm) paper. The worksheets are designed to fit on either paper without the need to resize them. Do not use “fit to page.”

If you do not have a printer that can print on that size of paper, we recommend that you take the files to a photocopy shop or a printer who does have a suitable printer. The files will fit on floppy disks.

It is also possible to prepare the masters using only a Letter or A4 size printer. Use one of the following two methods; “Fit to Page” or “Cut and Paste:”

FIT TO PAGE – First download the Tabloid/A3 format document. Print it on Letter or A4 paper using the “Fit to page” option. Then enlarge the printout onto Tabloid/A3 paper using a photocopier. There is a scale incorporated into the design so that you can check that the enlargement ratio is correct. If the quality of output from your printer and photocopier if not good enough (which is quite likely) you may have to use the “Cut and Paste” method…
CUT AND PASTE – Download and print the Letter/A4 format document on Letter or A4 paper. Do not use the “fit to page” option. Each large page is spread across two smaller pages. One of the two pages has a shaded area with a wavy edge. Cut the shaded area completely away from that page.
wheel
CUT OFF THE SHADED AREA
The wavy edge of that page will now fit over the other page to make a full-sized image. Glue them together, aligning them carefully. The alignment arrows will meet as shown on the right.

We recommend using a Glue Stick for this job.

Do not be alarmed if they will not align perfectly, because computer printers do not usually produce pages that match perfectly. A close match is sufficient and minor kinks in some of the lines where the pages join will generally go unnoticed. Use the joined printout as a master for photocopying onto Tabloid or A3 paper.
wheel
PASTE THE TWO SHEETS TOGETHER

wheel
THE ALIGNMENT ARROWS WILL MEET

Stage 2 – Cutting out and assembling a Star Wheel

1.

Cut the pocket.
  • For a single-sided Star Wheel you will have one sheet to cut, for a double-sided Star Wheel you will have two.
  • Cut slowly and carefully, keeping to the lines.
wheel
CUT AROUND THE EDGE
After you have cut around the edge, fold the paper without creasing and give it a single snip with the scissors to make a hole in the window.

wheel
GIVE IT A SINGLE SNIP
This lets you get your scissors into the window without crumpling the paper.
wheel
GET YOUR SCISSORS IN
Cut the window out.
wheel
CUT THE WINDOW OUT

2.

Fold the tabs back.
  • Fold the tabs on the pocket accurately.
  • Some adult help might be needed with adjusting the folds.
wheel
FOLD THE TABS

SINGLE SIDED STAR WHEEL

If you are making a double-sided Star Wheel, jump to the double-sided instructions.

3.

Insert a single sheet of Letter size or A4 paper under the tabs…

wheel
INSERT A SHEET OF PAPER
and tape it into place with sellotape/scotch tape.
wheel
TAPE IT INTO PLACE

4.

Cut out your wheel. Cut slowly and carefully, keeping to the line.
wheel
CUT OUT YOUR WHEEL

5.

Put the wheel in the pocket and cut the pocket to shape.
  • You can cut the pocket to any shape, or even leave it uncut if you wish.



Your star wheel is now ready to use.

Star wheels can be decorated with coloured pencils or felt pens if desired.

If you want to add a pocket liner, see Adding a Pocket Liner. Otherwise jump to Follow Up and Extension.
wheel
CUT TO SHAPE

DOUBLE SIDED STAR WHEEL

3.

Insert the back of the pocket under the tabs...
wheel
INSERT THE BACK
and tape it into place with sellotape/scotch tape.
wheel
TAPE IT INTO PLACE

4.

Cut out both wheels. Cut slowly and carefully, keeping to the lines.
wheel
CUT OUT YOUR WHEELS

5.

Place the two wheels side by side, printed side up. Turn them so that the degree numbers around the edge match at the point where they touch.
wheel
PLACE THEM SIDE BY SIDE
The degree marks will look like this where the wheels touch.
wheel
THEY WILL LOOK LIKE THIS

6.

Pick up the two sides of the wheel like this keeping the numbers lined upů
wheel
PICK UP LIKE THIS
and put them together, back to back. Now is the time to check that the degree numbers match from front to back.
  • It is not necessary for them to match perfectly; a few degrees out will not make a noticeable difference.
  • You can hold them up to a bright light source to help check the alignment.
wheel
PUT BACK TO BACK

7.

Peg the two sides together with clothes pegs, bulldog clips, paper clips, or something similar.
wheel
PEG

8.

Glue the two sides together. Apply the glue thinly and evenly.


These instructions are for gluing two single-sided photocopies back-to-back to make a double-sided wheel. This is not the only way to make a double-sided wheel. It can be done with double-sided photocopying. In our experience it is difficult, if not impossible, to get the designs on both sides of the paper to line up with each other on a photocopier. Attempts to produce double-sided wheels this way can be frustrating. However, if your photocopier has the facility to adjust the registration of double-sided copies then you may be able to produce wheels this way and avoid the need for glue altogether.

wheel wheel
GLUE

9.

Remove the clothes pegs and gently smooth any wrinkles out of the wheel.
  • It you have done the gluing quickly enough there will still be “slip” in the join to allow wrinkles to be smoothed out.
  • Let the glue dry before you put it in the pocket, otherwise you will make the pocket sticky.


10.

Put the wheel in the pocket.

Your Star Wheel is now ready to use.

Star wheels can be decorated with coloured pencils or felt pens if desired.

If you want to add a pocket liner, read on… Otherwise jump to Follow Up and Extension.

Adding a pocket liner

Adding a pocket liner makes the Star Wheel a little easier to use, and makes it a little more durable.

A pocket liner is a plastic L-pocket letter file. L-pocket letter files are open along two sides. They are available from stationery suppliers.

Examine your L-pocket letter file. There should be a folded edge down one edge, and a seam down the other. Cut the seam off as neatly as possible.
wheel
CUT OFF THE SEAM
Now your L-pocket file is open along three sides. Put it into the pocket. Make sure it sits right into the corner of the pocket. Make sure you have put it the right way round so that you can still get the wheel in and out of the pocket.

Put sellotape/scotch tape on to keep it in the pocket. The places where you should put tape are highlighted in the photo on the right in yellow. You can put tape in more places than that if you wish.

Turn the pocket over and put sellotape/scotch tape on the back too in the same pattern.
wheel
TAPE IT INTO THE POCKET
Trim off any excess plastic.
wheel
TRIM

Follow Up and Extension

As soon as you have completed a star wheel you should have a brief introduction to setting and using it. Take a few minutes to do the following:
  • Look at the dates around the edge of the wheel, and the times around the edge of the pocket. Note that there are separate time rings for daylight saving and standard time. (Your pocket will not have daylight savings times if you live close to the equator.)
  • Put your wheel in its pocket and set your Star Wheel to 10pm. Teachers should check that all of your students can do this.
How to set a Star Wheel
  1. Make sure you are using the correct clock ring – daylight saving or standard time.
  2. Line up today’s date with the time.
  3. Keeping the date lined up with the time, turn the window until the direction you are looking in is at the bottom.
  4. The bottom part of the window will show you the stars in that direction.
  5. If you have a double-sided star wheel, keep the date and time lined up when you flip it to look at the back window.
Teachers should also demonstrate the use of the Star Wheel with Mirapla Sky on the computer. Keeping the wheel set for 10pm tonight, launch Mirapla Sky and use the Star Wheel to identify the Big Dipper, Cassiopeia or the Southern Cross from the stars shown on the computer screen. This demonstrates to the students that the Star Wheel they have just made really works.

(Instructions for using Mirapla Sky are included in the worksheets for Activity 2 – The Stars as a Compass. There is also on-screen help available in the program.)

Downloadable Resources

Wheels and Pockets
Download a set of ready-to-print wheels and pockets for a Star Wheel. Not a subscriber? Preview as a web page here.

Mirapla Sky for Windows

Help with printing and downloading

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URL http://www.AstronomyInYourHands.com/activities/makestarwheel.html   Publication date 6 Nov 2002
Copyright © C J Hilder, 2002. All rights reserved.
 


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