**Experiment to Test Protein**

To test the presence of protein in a sample, you can perform the Biuret test. The Biuret test is a simple and widely used method to determine the presence of proteins in a solution. It is based on the reaction of proteins with copper sulfate in an alkaline solution.

**Materials Required:**
1. Protein sample (e.g., egg white, milk, etc.)
2. Biuret reagent (a solution of sodium hydroxide and copper sulfate)
3. Test tubes
4. Test tube rack
5. Distilled water
6. Pipette or dropper
7. Bunsen burner or hot plate (optional)
8. Safety goggles and lab coat

**Procedure:**

1. Prepare the protein sample: Take a small amount of the protein sample (e.g., egg white) and place it in a test tube. If the sample is solid, grind it into a fine powder before placing it in the test tube.

2. Add Biuret reagent: Using a pipette or dropper, add a few drops of the Biuret reagent to the test tube containing the protein sample. Make sure to mix the contents of the test tube gently.

3. Observe the color change: After adding the Biuret reagent, observe any color change in the solution. If proteins are present in the sample, the solution will turn from blue to violet or purple. If no color change occurs, it indicates the absence of proteins in the sample.

**Explanation:**

The Biuret test is based on the reaction between proteins and copper ions in an alkaline solution. The copper ions in the Biuret reagent form complexes with peptide bonds in proteins, resulting in a color change. The intensity of the color change is directly proportional to the concentration of proteins in the sample.

In this experiment, the protein sample is mixed with the Biuret reagent. If proteins are present in the sample, they will react with the copper ions in the reagent, forming a violet or purple complex. This color change occurs due to the formation of a coordination complex between the peptide bonds and copper ions.

The Biuret test is specific to proteins and does not react with other compounds such as carbohydrates or lipids. Therefore, it is a reliable method to determine the presence of proteins in a sample.

**Note:** It is important to handle chemicals and laboratory equipment with caution. Always wear safety goggles and a lab coat to protect yourself from any potential hazards.