Gather capped test tubes, paper cups, rubbing alcohol, water, salt, plastic stirrers, and flat wood sticks. Dissolve two teaspoons of salt in one quart of water. Give each student ten milliliters (.01 oz) of the solution in a cup. In another container, mix three parts water with one part liquid detergent. Label test tubes and pour one teaspoon of this mixture in each. In separate test tubes, add two teaspoons of alcohol, seal, and store in refrigerator until cold. Tell students to swish the salt solution in their mouths for thirty seconds, spit back in the cups, and pour into the detergent-labeled tube. Cap the tube and rock gently from side to side for two or three minutes. Open and pour the alcohol down the side of the tube. Observe two layers with the alcohol on top. Let mixture stand for one minute. Use plastic stirrer to slowly push some of the alcohol into the soap layer and watch DNA separate from the soap. Twist the stirrer around it to extract the strands.
Assemble warm water, clear liquid soap, cold rubbing alcohol, baking soda, meat tenderizer, and a banana. Equipment required includes two plastic cups, measuring cup, measuring spoons, plastic stirrer, strainer, funnel, tall narrow jar, and toothpicks. Measure 1/2 cup of warm water into a plastic cup. Add 1/2 teaspoon mashed banana and mix well. Include 1/2 teaspoon liquid soap and stir for one minute. Add 1/4 teaspoon of tenderizer, along with 1/2 teaspoon baking powder. Stir for another minute; let solution settle and cool. Pour the thick top half of the mixture through a strainer into another cup. Transfer to two test tubes until each is about half full. Carefully add alcohol but don't stir. Observe two layers with bubbles between. Place the tip of a toothpick just below the alcohol layer and turn in very slow circles until globs of strands stick to it. Keep turning as long as threads keep coming. Pull out and observe the DNA of a banana.
Find a piece of raw liver; students will love the yuck factor. Supply a blender, clear glass container, strainer, toothpicks, clear liquid soap, warm water, and rubbing alcohol. Cut liver into small pieces and place in blender. Cover with warm salty water and blend for five to ten seconds. Strain into a glass until it's half full. Add two to three teaspoons of soap and stir carefully. Pour alcohol in until glass is almost full. Rest for three to five minutes. Notice the DNA coming from the nucleus of the meat cell rising to the top. Twist the DNA around a toothpick.
Collect split peas, clear liquid soap, colored liquid soap, powdered soap, meat tenderizer, salt, rubbing alcohol, cold water, measuring cups, small glass containers, measuring spoons, straws, and a strainer. Blend 1/2 cup split peas, 1/8 teaspoon salt, and one cup cold water, for fifteen seconds on high. Pour through strainer into a cup and swirl to mix. Let stand for five to ten minutes. Pour into glass container to 1/3 full. Add a pinch of meat tenderizer and stir gently. Pour in alcohol until container is 2/3 full. Collect DNA from the top layer by winding it around a straw. Repeat experiment with colored and powered soaps and compare the results achieved with each.