RESPOND+TO+STIMULI

Brandon Latteri Matthew Song Janie Vicchio erik kringlen

Problem:Find out if the unknown substance is living.

material per group: 1. unknown substances A, B, & C 2. microscope slides 3. cover slips 5. 0.9% NaCl solution 7. 10% NaCl solution- concentrated 8. distilled H2O 9. paper towel pieces 10. microscope

procedure: 1. obtain unknown substances A, B, & C 2. Place a few grains of each onto their own microscope slide; making sure the unknown substance is spread over the slide. 3. One at a time, add one drop of 0.9% Nacl solution,add a cover slip to the unknown substance being tested. Tap the end of the coverslip gently with the end of an eraser to drive out any air bubbles. 5. observe under low first (100X), then high power (400X). Draw at the magnification you see best. 6. Add 1-3 drops of 10% NaCL to the edge of the cover slip. 7. Draw the solution under the coverslip by touching the opposite side of the cover slip with some paper towel. 8. Observe the changes in the unknown substance when the solution changes from 0.9% to 10%. Observe under low first, then high power. Draw at the magnification you see best. 9. Add 1-3 drops of distilled water to the edge of the coverslip by touching the other side with a paper towel. 10. Observe the changes under a low, then under high power. Draw your magnification under the best you see. 11. For a control comparison, the skin of a purple onion will be obsrved in .9% NaCl, 10% NaCl, and distilled water under low and high power and drawn at high power.

Control: Purple onion Independent variable: Unknown A,B,C Dependent variable:

Unknown A: The unknown is living and did react to the saltwater. The cells enlarge when they react with salt water.

Unknown B: The unknown is living and did react to the salt water. The cells enlarged when they reacted with the salt water

Unknown C: The unknown is living. It did not react to the salt water.