Conducting Experiments in Science

Upper School students are conducting experiments at home led by Mrs. Sarah Schlussel, Upper School Biology Department Chair. The experiment she led was to extract DNA from a substance, which is part of a unit on DNA in the Forensic Science 2 class. The students are learning about the forensic techniques that allow DNA to be used in criminal cases.
The first step was to extract the DNA from from blood, or saliva, or a hair follicle for instance - clues that would be discovered at a crime scene. The technique used is just about the same for any living cells – including fruit. For this experiment bananas, strawberries, kiwi, and peas worked best. Students used whatever they had available at home.
In the video demonstration, Mrs. Schlussel walked students through the experiment which uses three glasses, a banana, clear shampoo, salt, toothpicks, plain coffee filters or paper towel, a fork, water, and a solvent such as rubbing alcohol. Using the buffer solution, the cells of the banana will be broken apart with some coaxing. She added salt to the water, squirts of shampoo and used the fork to mix the buffer solution that, when combined, would make the banana cells come apart. The concoction was strained through the coffee filter or paper towel to get a small amount of fluid. The remaining banana liquid was mixed with the solvent which created two layers, one clear layer at the top and one cloudy layer at the bottom. By swirling the toothpick through the liquid, she could separate the strings of banana DNA in the bottom layer.
The Upper School continues to engage students through lectures and innovative activities virtually to continue our pursuit of academic excellence.