Snail and Elodea Investigation

Directions: Plan an investigation to collect data to support or contradict 7 hypotheses proposed in this investigation.

Questions: How are plants and animals interdependent on one another? How is carbon cycled between plants and animals?

Hypotheses: 1: Snails give off CO2 in the light. 2: Elodea takes in CO2 in the light. 3: Elodea uses CO2 snails give off in the light. 4: Snails give off CO2 in the dark. 5: Elodea takes in CO2 in the dark. 6: Elodea uses CO2 that snails give off in the dark. 7: Elodea gives off CO2 in the dark.

Materials • glass vials with lids • test tube rack • distilled H2O • pond snails: Lymnaea • water plants: Elodea • bromthymol blue (BB) • straw (to add CO2) • wax pencil • lamp with 60 watt bulb • dark cabinet

Procedure: Brainstorm Hypotheses 1-3 H1: Snails give off CO2 Experimental vs. Control set-up H2: Elodea takes in CO2 H3: Elodea uses CO2 snails give off

Hypotheses 4 -7 How will you set these up? Infer an appropriate design to test hypotheses 4-7 Create a table to represent the experimental and control procedure Make specific predictions for experimental and control treatments