Here's how it works:

* Biuret reagent is a solution containing copper(II) sulfate and sodium hydroxide.

* When added to a solution containing protein, the copper ions in the reagent react with the peptide bonds in the protein molecules.

* This reaction produces a violet-purple color which indicates the presence of protein.

Here's a simple experiment you can try:

1. Prepare your samples:

* Use two clear test tubes.

* In one tube, add a small amount of a known protein solution (like milk or egg white).

* In the other tube, add a small amount of a non-protein solution (like water or sugar solution).

2. Add Biuret reagent: Add a few drops of Biuret reagent to each tube.

3. Observe the results:

* The tube containing the protein solution will turn violet-purple.

* The tube containing the non-protein solution will remain blue (the color of the Biuret reagent itself).

Important Note: While the Biuret test is a good indicator for protein presence, it's not a definitive test for protein content. Other compounds can react with Biuret reagent, resulting in a false positive.