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Chelating Iron Experiment


In this experiment we use household products to demonstrate how tannic acid (often found in tea) can be used to react with the iron found in food materials such as plants to create another compound. This type of reaction shows how tannic acid inhibits iron absorption from these foods.

Difficulty: Medium


  1. Water

  2. Bowls

  3. Hot water or microwave for boiling water

  4. Tea leaves or powder

  5. Lettuce or any plant material

  6. Coffee filter

  7. Strainer or filter for tea leaves


  1. Boil water and add the tea leaves (about 3 tablespoons of tea leaves), careful, it is going to be hot!

  2. Let this sit for 10 mins so it can be steeped for a good tea color

  3. Take the lettuce and blend it in a blender with required water

  4. Filter the lettuce juice using a coffee filter in a cup, save it

  5. Now filter the tea leaves and water, save it

  6. Now take the two saved liquids - one with the lettuce juice and the other with the filtered tea leaves and mix it together

  7. Within a few seconds you will see that there are iron particles at the bottom of the container

How It Works:

Many foods that we eat contain iron, an important nutrient in our everyday lives. This experiment shows that we can separate out this iron from our foods using tea. Tea contains a compound called tannin, which stops from absorbing iron. This means that tannin prevents the iron from being absorbed and dissolved into the solution and instead it forms a new compound with the iron. The new compound is seen in the black chunks at the end of the experiment.

When tannins from tea mix into the liquid it forms tannic acid. This tannic acid is then able to react with the iron ions (Fe3+) to create a new compound. The iron ions are formed when iron is dissolved in a liquid.


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