Planaria are free-swimming mostly freshwater flatworms. Flatworms are very unique creatures because they regenerate lost parts. My groups experiment was, The Effect of Darker Regions on Planaria Movement. The purpose of this experiment was to see whether or not the planaria preferred the white region or the dark region. My hypothesis was, If the Planaria are placed on the white side then they will move to the dark side because the planaria have a strong negative geo-tropism and would move away from white side and go to the dark side. The independent variable was the two sides of the petri dish, which had one white region and one dark region. The dependent variable consisted of how many planaria moved to the dark side. First thing my group did was assemble two petri dishes into one by taping them together and having a hole in between the two petri dishes, so then the planaria can move from one side to another freely. The petri dishes when combined formed a make-shift reservoir for the planaria. We then filled both petri dishes with 25 ml of water and covered the outsides of each petri dish with a white paper and a black paper. We then placed the planaria on the white side and waited 5 minutes. When the 5 minutes were up we counted how many planaria were on the white side and the dark side, then we put the data found in a table. We then repeated this process two more times to get more accurate readings. Our constants in this experiment were, 5 minutes per trial, planaria were placed in the middle of the white section, petri dishes, colored paper, elevation of petri dishes, room temperature, and same type and amount of water. To see if our hypothesis was valid more than 50% of the planaria had to move to the dark side. Horizontal view of the hole in the petri dish where the two petri dishes are combined Overhead View of petri dish
Number of Planaria in Dark Side |
Trail 1| Trial 2|...