Yeast is something that most students come into contact with on a daily basis and have even seen their parents baking with. Few students, however, realize that yeast is a living organism. To test this fact, students will set up four test tubes labeled one through four. The first two test tubes will contain yeast, sugar and water. The second two will have yeast and water. Fill test tube one 4/5th of the way with water and a packet of yeast. Equally distribute the water and yeast mixture among the four test tubes. Add one-half a packet of sugar to test tubes one and two. Fill each test tube 4/5th-full with water. Cover each test tube with a balloon and shake vigorously. Observe changes in the tubes and balloon every five minutes for 25 minutes. If the yeast is alive, it should produce a gas when sugar is available for food.
Have a student swish a small cup of sports drink around in his mouth for a minute to extract DNA from cheek cells, then spit the liquid back in the cup. Add .25 mL of detergent to a test tube, then carefully add the sports drink until the tube is half full. Add a pinch of meat tenderizer (enzyme) to the tube and, placing your thumb over the top invert the tube five times. After 10 minutes slowly add 2 cm of rubbing alcohol to the tube and let sit another 10 minutes. Students will be able to see DNA visible as clumps of white floating in the tube.
Place 90 red, black and white pom-poms on a large piece of rough black fabric and call it the black forest. Then place the same amount of pom-poms on a large piece of red fleece and call it the red grassland. Give each student a plastic fork, spoon and knife along with a plastic cup. Assign students to a habitat and say, "Go." Students have 30 seconds to capture pom-poms using only the utensils provided and place them in their cups. Count the number of pom-poms captured in each habitat by color. Students should notice that fewer black pom-poms were captured in the black forest and fewer red pom-poms captured in the red grassland. Discuss how this represents natural selection.
After teaching students about the structure of a cell, have students create an edible model of a cell. Students must decide whether to create a plant or animal cell and use lab time to construct and label the cell using items brought from home. Require all models to be made out of edible materials that can remain fresh for at least three days without refrigeration. Allow students to use plastic wrap, toothpicks, paper and a round plastic container to help with the cell's structure.