Whether you have an assigned science project, or you just like building models, making a double helix model to represent DNA is relatively easy with multi-colored beads and craft wire. Using five different bead colors to denote the basic components of the double helix, you can create a DNA model that accurately informs and educates you and your audience about this fundamental building block of life.
Pick out four colors of bugle beads to represent Adenine, Thymine, Guanine and Cytosine to indicate the chemical bases that constitute the rungs of the DNA ladder. Use silver bugle beads to represent the sugar and phosphate molecules that form the sides of the ladder. You need wire that is highly flexible and thin enough to thread through a bugle bead hole twice. Choose a fine craft wire 28 to 30 gauge in thickness.
Begin constructing the base pairs of your double helix. Cut at least 2 feet of craft wire with your metal clippers. Thread the fine wire through the first pair of bugle beads. Start with the beads that represent Adenine and Thymine. Keep in mind that Adenine connects to Thymine to form a base pair and Guanine connects to Cytosine. Move the pair of threaded beads to the center of the piece of wire and add a silver bugle bead on either side of your Adenine and Thymine base pair beads.
Create the first beaded loop. Thread two beads representing Guanine and Cytosine on one end of the wire. Take the other end of the wire and thread it through the Guanine and Cytosine beads from the opposite direction, so that both ends of the wire are threaded through the same two bugle beads from opposite sides. Pull gently on both ends of wire to tighten the beads into a loop.
Add a silver bugle bead to the wire ends on each side of the loop. Thread an Adenine bead and a Thymine bead to one end of the wire, and thread the other wire end through the two beads from the opposite direction. Pull the wires tight to create another loop. Continue creating bead loops, alternating between base pairs of Adenine and Thymine rungs and Guanine and Cytosine rungs with the silver beads separating each rung of the DNA ladder.
Repeat this process until the double helix is the length you want. On the last rung, clip the excess wire on both sides, leaving an extra centimeter to thread back through the silver bugles on each side. Grip each end of the beaded ladder between your thumb and forefinger, and twist it into a spiral. Choose a mode of presentation for your double helix. Some ideas could include mounting the double helix on a nicely matted piece of poster board, or hanging it from a stand.