Lab report Essay

Submitted By jaber_luma
Words: 329
Pages: 2

Luma Jaber
Bio 111, Section 11
Lab Report: Searching for Starch
The Purpose of this experiment is to find out if an unknown solution contains Starch. Using chemicals and observing color change will determine what the solution contains. The chemical that will be used in Iodine solution. When starch is present, Iodine solution reacts chemically with starch and changes in the way iodine molecules are able to reflect light. The original color of Iodine solution yellowish-brown, if starch is present the color will change to a blue-black color. Materials that will be needed are wax pencil, and five clean test tubes. Label and mark the test tubes at 1 cm. With Tube 1 fill to the 1 cm mark with water, and five drops of Iodine solution. Then observe the color change, and record your observation. Then fill Starch suspension in Tube 2 until 1 cm mark. Then add 5 drops of iodine solution and shake well. Record your observation. In Tube 3, add a few drops of onion juice (obtain the onion juice by adding water and crushing a small piece of onion with a mortar and pestle.) Add five drops of Iodine solution. Observe and note color change. In Tube 4, add a few drops of potatoes juice, then add 5 drops of Iodine solution. Observe and note color change. Finally, In Tube 5 add glucose solution and add five drops of iodine solution. Observe and note color change. If starch is present a blue-black color will appear. According to our observation, Tube 1, 3, and 5 (water, onion