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Discovering DNA’s Double Helix

Activity Description

Students make a 3D model of DNA to learn the basic structure of DNA and the nucleotide base pairing rules. 

Estimated Time of Activity

Up to 1.5 hours

Activity Objectives

Students will be able do the following as a result of the activity:

  1. Describe the 3 basic parts of a DNA molecule
  2. Name the four types of nucleotide bases
  3. Explain the rules of base pairing for DNA

Activity Prerequisites

Students should be able to articulate a definition of DNA and describe in general terms what it does in the cell. 

Activity Instructions

  1. Draw a stick model of DNA
  2. Use the red licorice, marshmallows, and other materials to make the DNA model
  3. Label the backbone and four bases on the helix model


The models are assessed for accuracy. Every student should end the class with a correct and labeled 3D model of the specified DNA sequence. 


  • Student handout
  • Licorice sticks: 2 per student
  • Colored marshmallows per student: 9 green, 9 pink, 9 yellow, and 9 orange
  • Toothpicks: 12 per student
  • Paperclips: 5 per student
  • Masking tape

Instructor’s Notes

See Instructors handout