How To Use

by Camilla Barry

Barry Scientific

CONCEPT: Geometry, Measurement and Polygons

SKILLS: Using a protractor to make polygons and find midpoints

MATHEMATICS STANDARDS: Grades 4-8 geometry

MATERIALS: Barry Scientific Protractor, card stock, pencil, scissors, glue, tea light candle (optional)

Attaching two pentagons

1. Make 10 regular pentagons with radii of 5 cm. (See our Making A Polygon lesson plan for instructions.)

If students are working individually, they may want to photocopy their pentagons so they won't have to construct all 10.

2. Find and mark the midpoint of each side on the pentagon. Connect the midpoints to make a smaller pentagon inside the larger one. Score (press hard on) these lines to help you fold them later. (Figure 1)

3. Cut out all the pentagons. Fold the tabs down along the lines connecting the midpoints. (Figure 2)

4. Attach two pentagons together by overlapping the tabs. Glue the tabs down. See "Attaching two pentagons" picture at left.

NOTE: It is easy to misunderstand this step. The tabs should not be glued to each other. The shaded tab is glued to the inside face of the right pentagon, and the unshaded tab is glued to the outside face of the left pentagon.

HINT: It helps to line up the fold lines when gluing the tabs.

Making a ring

5. Continue to attach pentagons to make a chain of five. Bring together the ends and overlap the tabs, gluing them as before, to create a ring. See picture "Making a ring" at left.

PAY ATTENTION to the way you connect them. The tabs at the bottom of the ring will create a star if you have done it correctly.

6. Repeat steps 4 and 5 to create a second ring.

Folding in the tabs

7. Fold the tabs at the bottom of each ring to the inside and glue down. In the picture at left ("Folding in the tabs"), one tab has ben folded inside and glued down.

8. One ring is the top of the lantern and the other is the bottom. Connect the two rings by overlapping and gluing their remaining loose tabs as before. Position the two rings before gluing to make sure they will line up correctly.

9. Once glued, the lantern will be beautiful even if there are slight gaps. Insert a tea candle and light it.
Starlike figures should appear on each pentagonal face as a result of the single and double layering of paper.

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