How to Build a DNA Model for a Project

Updated February 21, 2017

The creation of a model of a strand of double-helix-shaped DNA (deoxyribonucleic acid) is one of the more popular ideas for a science project out there and can be suitable for many grade levels. Creating a DNA model from the foam balls found in arts and crafts stores is inexpensive, but requires effort from the student to make sure that the double helix shape is evident and that the structures are factually accurate.

Glue the wood dowel, pointing up, with wood glue to the centre of the wood base.

Allow it to dry thoroughly.

Paint half the 1 1/2-inch foam balls in one of your six colours. Paint the other half in another colour. These balls will represent the sugar phosphate compound that forms the sides of the double helix DNA structure. Allow it to dry.

Paint a quarter of the 1-inch foam balls in another of the six colours. Paint each of the other three quarters of foam balls with a new colour until all the foam balls are painted and all the colours have been used. Allow it to dry. These four colours represent the four nitrogen bases: adenine, thymine, cytosine and guanine.

Create the first "rang" of your DNA model by threading two different colours of 1-inch foam balls on one of the craft sticks. These two balls represent a nitrogen base pair, either adenine and thymine, which always pair up, or cytosine and guanine, which do the same. Put one of the 1 1/2-inch foam balls on each end of the craft stick, using the same colour for both. This 1 1/2-inch ball represents a sugar molecule.

Wire the centre of the craft stick to the dowel at the bottom.

Use a toothpick to attach the one of the other colour of 1 1/2-inch foam balls to one of the balls representing the sugar molecule. You'll want to angle the toothpick somewhat, so that if viewed from above, it will seem to be going clockwise. This other colour of foam balls represents a phosphate molecule. Attach another phosphate molecule foam ball to the other sugar molecule ball, mirroring the one that you just did.

Stick toothpicks halfway into both phosphate molecule balls in preparation for the next rang of sugar molecules sandwiching a nitrogen base pair.

Continue creating rungs with either a cytosine and guanine pairing or an adenine and thymine pairing, attaching the sugar molecule balls on the rang to the previous phosphate molecule balls, wiring the rang to the dowel and attaching new phosphate molecule balls until you've gone up the whole length of the dowel.


So long as adenine and thymine are paired and cytosine and guanine are paired, it doesn't matter in what order you put the pair on the craft stick or in what order you place the rungs.


Be careful with the wire, as it can be sharp. This project should be done with parental supervision when elementary-aged children are making it.

Things You'll Need

  • Wood base
  • Wood dowel
  • Wood glue
  • 1 1/2-inch diameter foam balls
  • 1-inch diameter foam balls
  • Craft paint in six colours
  • Paint brush
  • Craft sticks
  • Craft wire
  • Toothpicks
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About the Author

Antonia Sorin started writing in 2004. She is an independent writer, filmmaker and motion graphics designer based in Raleigh, North Carolina. She has completed work for the Long Leaf Opera Company, the former Exploris Museum and the Leukemia and Lymphoma Society. She graduated from Thomas Edison State College in New Jersey with a Bachelor of Arts in communications.