Ask what is the last thing that plants need for photosynthesis to occur? Light- Note: teacher should go around and turn on lights and seal lids on biochambers Do not touch the light bulb, it will get hot! Look inside biochamber- what part of the plant is in there? Leaves Leaves have water, there is CO2, and light- what are the leaves going to produce? Look at equation: sugar and O2 Is oxygen a solid, liquid, or a gas? Gas How does the O2 get out of the leaves? The holes/lips (stomata) allow for the oxygen to leave the leaves Point to photo on Smartboard Part 2: Before you collect data, what do we need to do? Make prediction Point out the CO2 probe on top of the biochamber. Explain that will measure the CO2 in the container during photosynthesis. Knowing what you now know about photosynthesis- make a prediction about what is going to happen to the amount of CO2 inside the sealed biochamber during photosynthesis. Will it be produced by the leaves and increase, or will be go into the leaves and decrease. Ask students to discuss with their lab partner and circle their prediction. Point out the O2 probe on top of the biochamber. Explain that will measure the O2 in the container during photosynthesis. Knowing what you now know about photosynthesis- make a prediction about what is going to happen to the amount of O2 inside the sealed biochamber during photosynthesis. Will it be produced by the leaves and increase, or will be go into the leaves and decrease. Now we are ready to start collecting the data using the hand held computer- LabQuest/ Tell the students how to turn on the Lab Quest by pushing the power button on the upper left side. See red arrow below. After the Lab Quest turns on, they should see two sensors on the screen Oxygen and Carbon dioxide. Ask what the units are for CO2- ppm parts per million. Ask students what the units are of O2? % Explain that they are going to change units to ppt. Ask one student touch the oxygen screen. They should see "change units." Have students change the units to ppt (parts per thousand). Explain that now are going to collect data. To collect data, have one student push the green arrow on the bottom left side of the Lab Quest.
Assessment: We collected data, recorded data, analyzed data so now it is time to… make a conclusion. Did the amount of CO2 increase or decrease? Decreased Did the amount of oxygen increase or decrease? Increased Is this what they predicted would happen? Show diagram of photosynthesis on Smartboard. Ask students to discuss with their partner what process the diagram shows. Photosynthesis Have students explain what plants need for photosynthesis to occur- water, sunlight, CO2 and what they produce- sugar and O2 As an exit ticket, ask whether this was an experiment or not. It was not. What was missing? There was no independent variable that we changed. What could be the IV? types of leaves, parts of plants, amount of light etc.. Extensions/Modifications: If you don’t have the entire 45 minutes, you can omit Part 1 and just have the students do the photosynthesis activity. If time permits, have students look at different types of leaves and seeds on walls and plants in biodome. Resources: VA DOE Enhanced Scope and Sequence References: Verneir website with tutorials for using labquests and probes