Discover the magic of DNA. These molecules are found inside just about every cell in your body – determining your physical attributes, including hair, eye and skin colour, and blood type. It’s the stuff that makes you, you. So, it’s no wonder scientists have been studying DNA for decades.
In this easy science experiment, you’ll learn how to extract your own.
What you’ll need
Narrow glass container like a spice jar or test tube (the narrower the container, the better)
10ml (2 teaspoons) ice cold isopropyl alcohol (80% or higher)
10ml (2 teaspoons) dishwashing liquid
1/4 teaspoon salt
1-3 drops pineapple juice
Small glasses or cups for mixing
Water for initial mouthwash
Skewer or fine sieve
Pour a small amount of water into a glass.
Take a mouthful of water and swish vigorously in the mouth for at least two minutes. Do not swallow the water.
Spit the water into a small cup.
In another cup, pour 90ml water and add the 2 teaspoons of dishwashing liquid. Stir the soap solution gently, minimising bubble formation.
Add 2 teaspoons of this soap solution into the water cup containing mouthwash (your spit).
Add salt to the mixture and stir using a spoon.
Transfer the liquid cell solution to the narrow jar until the jar is one-third full.
Add a few drops of pineapple juice into the jar and slowly spin the narrow jar to mix the juice.
Take the isopropyl alcohol out of the freezer and pour a small amount of the alcohol into a cup.
Pour 2 teaspoons of isopropyl alcohol into the jar slowly, allowing the alcohol to travel down the side of the jar and form a layer above the liquid cell mixture. (We recommend tilting the jar as your pour in the alcohol. Be careful, ensure no liquid spills from the jar and return to upright position).
Leave the jar stand for at least 5 minutes.
You should now be able to see a small amount of white web-like substance within the clear layer of the narrow jar. These are strands of your DNA clumped together!
The DNA strands can be a bit difficult to remove from this layer. If you want to give it a go, you can try using a sieve or using a skewer.
Skewer: Here’s the tricky part, gently insert the skewer into the top layer of the alcohol where a mass of white web-like strands should be forming. Twirl the skewer very gently in one direction only and lift the strands from the jar, placing them on a dark background.
Sieve: Tilt the jar and slowly pour the alcohol layer through the thin sieve, then place the DNA strands on a dark background.