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by | Mar 29, 2021

Science at home: How to extract DNA from a banana

Did you know 60% of your DNA is the same as a banana? No? Perhaps your child doesn’t either. Why not try this fun science activity that will allow you to see some DNA from a banana. It helps children create a mental image of DNA and gives them a taste of what being a scientist is like!

How to explain DNA

All living things including humans, plants (bananas!) and animals have DNA (deoxyribonucleic acid). DNA contains the instructions required to build each living thing.


You will need the following:

  • Two clear glasses/cups
  • Sealable plastic bag
  • Banana
  • Blunt knife and teaspoon
  • Plate/chopping board
  • Measuring jug
  • Either a colander/sieve/tea strainer
  • Either a coffee filter/dish cloth/paper towel
  • Black paper/card/black t-shirt/black jumper
  • Vodka/surgical spirit/rubbing alcohol (keep in freezer)
  • 4 teaspoons salt
  • 2 teaspoons washing up liquid
  • Warm water
  • Skewer (optional)



This activity requires adult supervision and safety glasses (or regular glasses/sunglasses).

Step 1: Chop up the banana.
Place the banana onto a plate. Use the knife to chop it up.

Step 2: Put the banana into a bag.
Place the banana pieces into a sealable plastic bag.

Step 3. Squash the banana.
Close the bag and gently squash the banana until smooth.

Step 4: Add salt to warm water
Fill the glass half full with warm water. Add the salt, then stir with a teaspoon until dissolved.

Step 5: Add washing up liquid
Add washing up liquid to the glass and stir.

Step 6: Pour into the bag.
Pour into the bag. Close the bag and squash gently for 10 minutes.

Step 7: Sieve
Put the sieve on top of the jug. Place the coffee filter in the sieve and pour the contents of the bag into it. Let the liquid drain through. This can take a while!

Step 8: Pour the drained liquid into a glass.
Pour the drained liquid into a glass. Place on top of the black card. Make sure you are wearing safety glasses!

Step 9: Ask an adult to carefully add the alcohol
Have an adult pour the alcohol down the side into your glass. Watch the bottom of your cup! White strands which look like cotton should appear. This is your banana DNA – the instructions to make a banana!

Step 10: Pick out the DNA!
You can use a skewer to pick out the DNA.

About the author

I was at university when I saw DNA for the first time. Instead of bananas I looked at mosquitoes. (The methods used to get DNA are similar whether it is from humans, plants, animals or even bananas.) I remember holding up the tube and adding the alcohol, like we did with our banana. As if by magic, the white, cotton-like strands of DNA appeared. It had an incredible effect on me – hopefully you and your children will enjoy the activity too.

Scientists all over the world are doing similar activities. It might be with smaller tubes and maybe the chemicals are slightly different but the end result is the same. They get DNA and use it to do things like help identify and treat inherited diseases, make sure there are enough crops to feed the world, catch criminals, solve archaeological mysteries, even create vaccines to prevent the spread of Covid-19.

I think it’s the best job in the world!

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