Make A Candy DNA Model | STEM Activity (2023)


Active Time

45 minutes to 1 hour

Total Project Time

45 minutes to 1 hour

Key Concepts

DNA, double helix, candy


Svenja Lohner, PhD, Science Buddies

Sabine De Brabandere, PhD, Science Buddies

Google Classroom


Ever wondered how DNA, the genetic blueprint of a life-form, can encode and pass on the information on how to grow and maintain that life-form? Just like a cookbook contains a complete recipe for a dish, DNA stores the recipe for the life of an organism. Although each human has a unique DNA sequence, the DNA in all of us is about 99.9% identical! In this activity, you will use pieces of candy to make a model for a short section of DNA—enough to get a sense of what DNA is like and how it encodes life.

This activity is not recommended for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.


  • Soft candy that comes in four different colors such as gummy bears, gum drops, or mini marshmallows (10 of each color)
  • Twizzlers (2) (or similar rope-like candy)
  • Toothpicks (5)
  • Paper
  • Pen (or marker)
  • Paper towel
  • Video instructions are available in English and Spanish

    Make A Candy DNA Model | STEM Activity (2)

    (Video) Make A Candy DNA Model!

Prep Work

  1. Clean the area you will work on, or plan to work with your candies on top of a paper towel.

  2. Sort your candies by color. Make sure you have at least 10 pieces of each of the 4 colors you will be using.


  1. DNA encodes the genetic blueprint of a life form using four chemicals. It is a long molecule that looks a little like a rope ladder, only about 200,000,000 times smaller! Give the long "ladder" a clockwise twist, and you can see why DNA is also called the "double helix." Following the instructions below, you will make a candy model of a piece of DNA. This will help you see what DNA looks like!

  2. DNA uses four chemicals (adenine, guanine, thymine and cytosine) to encode the data to maintain and grow an organism. These chemicals are abbreviated by the letters A, T, C, and G. We will use different colors of candy to represent each of these chemicals: yellow (A), red (T), green (G), and clear (G). You might use different colors. That's okay! Just be sure that you keep track of which color you are using to represent each chemical. (Tip! Take a piece of paper and label each of your piles with the letter of the chemical it represents.)

  3. These code chemicals are very particular. They always pair up in specific ways: A pairs with T, and C pairs with G. In your model, red only combines with yellow, and clear only combines with green. Use toothpicks to make colored pairs from your candies by sticking a candy on each end of the toothpick. Push the candies onto the toothpick so that the candies are pressed together in the middle, and you still have a bit of toothpick sticking out on each side, as shown below. You will create 6 pairs each of yellow-red and green-clear. No other combinations of colors are allowed. Note that in your body, these pairs are tiny and not colorful! Your candy model makes them look large and colorful. That makes the model easier to understand. Your DNA has a length of about 3billion pairs, so your candy DNA will only model a small piece of DNA—not the whole sequence!

    Make A Candy DNA Model | STEM Activity (3)

  4. DNA looks like a twisted rope ladder. In your model, you will use Twizzlers for the "backbone" sides of the ladder and then add the candy "pair" rungs. To assemble your DNA model, lay two Twizzlers parallel to one another with about 8cm of space in between.

  5. You will link the pairs of code chemicals to your DNA backbones by attaching each pair to the backbones so that the pair look like ladder rungs. Lay your pairs between the backbones, as shown below. (The order and orientation you choose, or the sequence is up to you.)

    Make A Candy DNA Model | STEM Activity (4)

  6. Take one toothpick that has a GC or AT pair of candies on it and stick the toothpick into the inside of one piece of the backbone (near the top). Then carefully stick the other end of the toothpick into the other side of the backbone so that your candy pair is connected to both sides.

  7. Continue to attach your other candy pairs to the backbones so they make parallel rungs. Leave about one or two centimeter of space between each rung. Do this until your backbones are connected by pairs from one end to the other.

    Make A Candy DNA Model | STEM Activity (5)

  8. Your candy DNA model probably looks something like the one below. Your sequence of pairs might be in a different order than this. That is okay! Lay your model on a piece of paper, and use a pen or marker to write the letters next to each piece of candy.

    Make A Candy DNA Model | STEM Activity (6)

  9. Your model is almost finished! One detail is missing: DNA is twisted. Hold one end of your model flat and carefully flip the other end over (180 degrees). This should create a twist!

    Make A Candy DNA Model | STEM Activity (7)

    What happens to the length of your DNA piece when you twist it? Do you see why DNA is called a double helix?

    Make A Candy DNA Model | STEM Activity (8)

  10. DNA can duplicate itself using the information contained in either strand, and you can too. To test, untwist your DNA model and lay it flat on a table or the ground. Hide one strand (a backbone with one side of each pair) with paper or a blanket. Your job is to use the knowledge you gained while making the DNA model to complete the section.

    Make A Candy DNA Model | STEM Activity (9)

    For each visible color (code chemical), can you tell which color (code chemical) is hidden? (Hint: look back at the second step of the procedure for help.) How could this help you duplicate your DNA molecule?

  11. To get an idea of how long human DNA is, count the number of pairs in your DNA section. Human DNA consists of three billion pairs.

    Make A Candy DNA Model | STEM Activity (10)

    Can you estimate how long your model would be if you modeled all the three billion pairs?

    (Video) How to make a DNA model out of Candy and Marshmallows!
  12. Take your ruler and measure how wide your DNA molecule is when untwisted. A real DNA molecule is about two nanometers or two millionths of a millimeter (2÷1,000,000 mm) wide.

    Make A Candy DNA Model | STEM Activity (11)

    How many times wider is your model than a real DNA molecule?

What Happened?

You were most likely able to tell what the hidden colors were, no matter which strand you chose to hide. This is because once you know one side of a pair, you know its partner as these chemicals always pair with the same partner: red with yellow; green with clear.

You probably have about 6 pairs in your model. You would need to make it 500,000,000 times longer to model all three billion pairs of human DNA. Your model would be about 60,000km (37,000miles) long, which is about 1.5times around the world!

Your DNA molecule is probably about 8cm wide. Real DNA is about 2nanometers or 2millionths of a millimeter wide. This means your model is about 40million times wider than real DNA.

This long string of DNA is coiled and folded into the center of almost every cell of the human body!

Digging Deeper

Plants, fungi, and humans might seem very different from each other, but they are all made up of tiny building blocks called cells, and—with very few exceptions—each of these cells has in its center a molecule containing the blueprint of the organism. This molecule is called DNA: deoxyribonucleic acid. Although the blueprint is different—after all, plants, fungi, and humans are very different organisms—the way it is encoded in DNA is identical.

The DNA molecule encodes all information using four chemicals: Cytosine [C], Guanine [G], Adenine [A], and Thymine [T]. It has two complementary strands, each with a long sugar-phosphate backbone to which the four chemicals attach. The sequence or order of these chemicals contains the data to maintain and grow the organism. In DNA, these four chemicals always link together to form pairs: A pairs with T and C pairs with G. In this very specific way, the two complementary strands link together to form DNA: a long molecule that looks a little like a rope ladder, only about 200,000,000 times smaller and twisted.

When organisms grow, their cells divide and in almost all cases, each cell receives a duplicate of the DNA molecule. DNA's ingenious structure allows for easy replication: each strand of the double helix contains all the information needed to create a new DNA molecule. If the pairs let go of each other, each backbone with its sequence of four chemicals can be the basis of a new DNA molecule. As A and T always pair up and C and G also always go together, one strand is enough to recreate the molecule.

Make A Candy DNA Model | STEM Activity (12)

Make A Candy DNA Model | STEM Activity (13)

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For Further Exploration

  • This model is made from candies. Can you create a model from paper and tape?
  • Take a piece of rope about one meter long. Twist the rope and keep on twisting. Do you see how a long string can twist and fold into a much more compact space? In a similar way, the DNA molecule twists and folds into a more compact entity.

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(Video) How-to Make a Candy DNA model


How do you make an edible DNA model? ›

Assemble one side of your DNA molecule. A piece of licorice will form the backbone and marshmallows will be the chemical bases. Place a marshmallow on the end of a toothpick so that the point of the toothpick goes all the way through. Anchor the toothpick into the licorice backbone.

How to make A 3D DNA model for high school biology? ›

To make a 3D model, we need to make two strands―sugar and phosphate―and then pairs of nitrogenous bases―adenine and thymine and cytosine and guanine. Just attach the bases like steps of a ladder between the two strands, twist them, and your DNA model is ready!

What 3 things make up the DNA model? ›

Each DNA strand is composed of nucleotides—units made up of a sugar (deoxyribose), a phosphate group, and a nitrogenous base. Each strand of DNA is a polynucleotide composed of units called nucleotides. A nucleotide has three components: a sugar molecule, a phosphate group, and a nitrogenous base.

What materials do you need to make a DNA model? ›

Suggested Materials: dry macaroni, string, pipe cleaners, wire coat hangers, beads, white glue, cardboard, styrofoam peanuts, toothpicks. Materials to avoid: anything that will mold, mildew, rot, melt, etc. such as marshmallows or gumdrops.

What would you need to do to your DNA model to make it look like A true DNA molecule? ›

To make your double helix, twist your model slightly so the molecule forms a spiral. DNA molecules have a right handed helix shape that winds in one direction. You can figure out the direction by sliding the fingers of your right hand along the backbone.

How does DNA look in 3D? ›

DNA adopts a complex 3D structure—like a ball of lint or a tumbleweed—but scientists have only recently begun to determine what these structures look like using new DNA sequencing technology.

What is the 3D structure of DNA? ›

Chromosomal DNA consists of two DNA polymers that make up a 3-dimensional (3D) structure called a double helix. In a double helix structure, the strands of DNA run antiparallel, meaning the 5' end of one DNA strand is parallel with the 3' end of the other DNA strand.

What does a DNA model look like? ›

They used Tinkertoy-like models to show that DNA is shaped like a twisted ladder. This shape is called a double helix. Watson and Crick also figured out that DNA is made of chemicals called bases .

How long is a DNA model? ›

Your model would be about 60,000 kilometers, or 37,300 miles, long—about 1.5 times around the world! Your DNA molecule is probably about four centimeters wide.

How can I do a DNA at home? ›

How to Collect DNA for a Home Kit
  1. 1) Understand what at-home tests versus court-admissible means. ...
  2. 2) Purchase a kit that pertains to your specific needs. ...
  3. 3) Pick the appropriate sample. ...
  4. 4) Be as sterile as possible. ...
  5. 5) Follow instructions for a buccal (cheek) swab. ...
  6. 6) Read the shipping instructions for your kit.

How do you make a DNA model with toothpicks? ›

Second: Connect two different coloured candies together using the toothpicks. Connect the toothpicks with the candy to the licorice strands so that the candy pieces are between the two strands. Next: Holding the ends of the licorice sticks, twist the structure slightly and you have a DNA model!

What sugar is found in DNA? ›

The sugar in DNA is deoxyribose. The pyrimidines are cytosine (C) and thymine (T); the purines are guanine (G) and adenine (A). The bases are linked by hydrogen bonds such that A always pairs with T and G with C.

How can I make DNA at home? ›

How to Extract Your Own DNA at Home
  1. Step 1: We Need. 500 ml water. ...
  2. Step 2: Add One Tablespoon of Slat to Drinking Water. ...
  3. Step 3: Gargle the Salt Water. ...
  4. Step 4: Add Clear Diashwashing Soap. ...
  5. Step 5: Mix Isopropyl Alcohol and 3 Drops of Food Coloring. ...
  6. Step 6: Pour Alcohol in the Salt Water Cup. ...
  7. Step 7: Results: Now We Can See DNA.

How do you make a DNA model with Popsicle sticks? ›

Paint three popsicle sticks red, three popsicle sticks green, three popsicle sticks yellow, and three popsicle sticks blue. Allow to dry for one to two hours. Use hot glue to affix six black popsicle sticks together lengthwise, at the ends, to create a long line. Repeat with the remaining six black posicle sticks.

What is the easiest way to get DNA? ›

There are several common sources of DNA that you can easily swab for. These include blood, feces, urine, semen, saliva, hair, teeth, bone, and tissue. DNA can also be collected from a variety of surfaces and materials.

How do you get DNA from strawberries? ›

Pull off any green leaves on the strawberry that have not been removed yet. Put the strawberries into the plastic bag, seal it and gently smash it for about two minutes. Completely crush the strawberries. This starts to break open the cells and release the DNA.

How many strands make up a DNA model? ›

A DNA molecule is made up of two linked strands that wind around each other to resemble a twisted ladder in a helix-like shape. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups.

What is the model of DNA? ›

Watson and Crick's DNA model

The structure of DNA is a double-stranded helix. The strands are bound with hydrogen bonds. Adenine bases are always joined with thymine bases, and cytosine bases are always joined with guanine bases. This is in accordance with Chargaff's rules.


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