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Year 2 Science

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Make Your Own Double Helix

dna

In Year 2, we learnt about Rosalind Franklin who was an important British scientist. We learnt how she did experiments and took X-ray photographs to discover the shape of deoxyribonucleic [dee-OX-ee-REE-bow-new-CLAY-ic] acid, or DNA. We say its shape is a 'double helix' that twists around itself a bit like a braid of plaited hair. Let's make our own double helixes out of pipe-cleaners to learn more about Rosalind Franklin's discovery.


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First, choose four pipe-cleaners of different colours. We chose to have a long green one and a yellow one, and the other two (pink and blue) we each cut into quarters, or four equal pieces. Have an adult carefully cut the pipecleaners for you using sharp scissors or wire-cutters. Place the small pieces horizontally (lying side-to-side) in between the two longer pipecleaners so it looks like a ladder.

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Next, carefully twist the ends of the small pieces (the ones like the rungs of the ladder) around the longer pipecleaners so that they hold in place. Make sure you don't prick yourself with the ends of the pipecleaners since they may be sharp. It doesn't matter in what order you place the colours of the small pieces, but try to space them evenly along the long pipecleaners.

Now you have a ladder with its rungs, but notice how Rosalind Franklin discovered that the shape of DNA twists around itself. To finish making our double-helix shape, hold on to both ends of your pipecleaner ladder and carefully twist your hands in opposite directions so that your ladder twists into a double helix like ours.

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What did you learn about the shape of DNA? You chose pipecleaners of different colours, and you chose which ones would be the long ones and which ones would be the short ones. You also decided in which order you wanted to put the coloured short pieces. Ours had green and yellow long pipecleaners and the rungs were: pink, blue, blue, pink, blue, pink, blue, pink. If you and your friends (or you and your whole class) made double-helix pipecleaners, you would each make the same double-helix shape, but they would be all different colours and the coloured short pieces would be in different orders. In the same way, DNA stores information that controls what we look like and how we develop. We each have different DNA because we are each unique: we're a little bit different from each other, and from our parents, but we are all still humans.

This activity supplements information from pages 335 - 336 of What Your Year 2 Child Needs to Know, which can be purchased here. Related activities:

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