DNA Cut a piece of paper into 1cm strips. Here are the strips. Cut the strips into 3cm lengths. Take about fifteen strips and cool ur one half of both sides blue. Folding in half then unfolding helps. Here they are. Colour the other half of those fifteen strips yellow on both sides. Now do the same with another fifteen, but this time colouring them red … … and green. Now cut two 70 cm lengths of masking tape and secure them sticky side up to a table using a small piece of masking tape at each end of each piece. Leave a gap of 2cm between them, and make sure they are parallel. Here they are. Now carefully place the strips across the gap between the two lengths of tape, so that a little of each end of the strip sticks to the tape. Leave about 1 cm between the strips. Continue all the way along your lengths of tape, arranging the strips randomly. Cut the ends off the lengths of tape, to release them from the table. Now carefully fold one length of tape back on itself, so that it covers the ends of the paper strips and sticks to itself. Continue along the entire length … … and repeat for the other strip. Now cut along the length of one piece of tape, so that only about 0.5cm remains. Do the same to the other length of tape. Your DNA molecule is finished, but it needs a twist. Tape one end to the table, hold the other end and gently turn your hand anticlockwise – this will give the molecule the correct twist. The molecule has a ‘right-handed’ screw. You could make several lengths of your molecule and stick them together, then hang them up as decorations. Make sure they have a right-handed screw twist. Your DNA double helix.