Colour, cut and stick cell pictures.
Living things are made up of cells, just like houses are made of bricks or duplo models are made of duplo. I had some duplo bricks for the little ones to play with as they arrived, so this was a nice way to include them.
Inside every single cell is a special code: DNA (DeoxyriboNucleic Acid) which tells cells how to make that particular living thing. DNA looks like long white strings, and we’re going to try and extract some of our own DNA so that we can look at it.
- Pour two tablespoons of water into a cup.
- Add a quarter teaspoon of salt to your water and mix well.
- Gargle (do not drink) the salt water for one minute (this is a bit yucky, you could ask a grownup to do it for you).
- Spit the water back into the cup.
- Put a tiny drop of washing up liquid into the cup, stir gently, don’t let it bubble up.
- Get 100ml (about 6 tablespoons) of cold isopropyl alcohol and mix in a drop of food colouring in another cup.
- Pour the isopropyl alcohol slowly on top of the salt water mixture so that you have two layers in your cup.
- Wait about three minutes.
- You should see white clumps and strings forming. That’s your DNA separating out.
The children enjoyed this activity a lot.
Break for drinks and snack.
DNA is made of little bits called nucleotides. Each nucleotide is composed of a nitrogen-containing nucleobase—either cytosine (C), guanine (G), adenine (A), or thymine (T) (as well as a monosaccharide sugar called deoxyribose and a phosphate group).
The Cs always pair with Gs, and the As always pair with Ts [show model]. We’re going to make some simple paper models, which will make something like the distinctive double helix shape of real DNA.
I used these templates, which I found online.
Teach Engineering have an activity you can download, so we can pretend to be forensic scientists using DNA evidence to solve a crime.
The children had a great time and managed this activity easily, with a little bit of help from parents.