Photosynthesis Investigation

Photosynthesis Investigation SOL 4.4c

Photosynthesis Investigation

Grade 4

SOL Thread & Objective

(Living Systems; SOL 4.4c) The student will investigate and understand basic plant anatomy and life processes. Key concepts include photosynthesis.

(Scientific Investigation, Reasoning, and Logic: SOL 4.1 a, c, d, e, h, i, j, k, m)

Essential Knowledge, Processes & Skills

The student will explain the process of photosynthesis, using the following terminology: sunlight, chlorophyll, water, carbon dioxide, oxygen, and sugar.

Description

Students will use a Vernier Labquest with an O2 Gas Sensor to measure the amount of oxygen produced by a plant during photosynthesis and use a CO2 Gas Sensor to measure the amount of carbon dioxide consumed by a plant during photosynthesis.

Inquiry Question

What happens to the amount of carbon dioxide (CO2 ) and oxygen (O2 ) during photosynthesis?

Essential Vocabulary

Leaf, photosynthesis, chlorophyll, oxygen, carbon dioxide

Inquiry Type

Structured

Expected Pacing (At EAGLES Center)

One 45 minute session

Safety Precautions

There are a lot of power cords with the equipment used in this lesson, please remind students to be careful and not touch any equipment until instructed by the teacher.

Prince William County Public Schools: Science Investigations

Photosynthesis Investigation SOL 4.4c

Materials:

(per student group)

LabQuest

Vernier O2 Gas Sensor

Vernier CO2 Gas Sensor

BioChamber 2000

Ring Stand with clamp

Flourescent bulb

Spinach leaves

Light Microscopes

Prepared slide of leaves

Set Up:

· Make sure all slides are pre-focused.

· Put layer of spinach on bottom of biochambers. Do not allow leaves to touch sensors. Leave the lid open to prevent condensation.

· Use the same spinach for all 3 rotations.

· Turn on labquests to make sure boot, then power off.

Procedure:

Part 1:

1. Before you begin: go over one rule, students should not touch the equipment until they are instructed to do so.

2. Ask students to make some observations and make a prediction about what they will be studying in this investigations. Plants

3. Explain that plants are incredible organisms. Ask students if they know where plants get their food? Make their own- process is called? Photosynthesis. Also, what do we call things that make their own food? Producers

4. Ask where does most of the photosynthesis take place in the plant? Leaves

5. Explain that they are going to get an up close look at plant leaves through a light microscope.

6. Explain that the only thing they are allowed to touch on the microscope is the light switch at the bottom. Have the students turn on the switch and look at the slide in the microscope.

7. Project the image of the plant cell on the Smartboard. Ask them to describe what they are seeing. Does anyone know what it’s called? cell

8. Review the parts they can see: Circles- nucleus, lines- cell wall and cell membrane, black specks- look like pepper- chloroplasts inside chlorophyll- site of photosynthesis

9. Ask the students if they see any pattern. Looks like lips- very important for photosynthesis. The leaf has holes. These are called stomata (“little mouths” in Greek)

10. What are those holes for? We will answer that in a little bit.

11. Ask the students to turn off their microscopes and look at the data sheet. Explain that they are now going to be chemists.

12. Ask them to point to the chemical formula for photosynthesis. Explain that what is on the left side of the arrow is what goes in (like the ingredients in a recipe), and the right side is what comes out (what is produced).

13. Looking at the equation, what is the first thing plants need to make their own food? Water

14. Looking at the formula, what is the second thing plants need for photosynthesis to occur? Carbon dioxide. Is carbon dioxide a solid, liquid, or a gas? Gas How does the CO2 get into the leaves? The holes/lips (stomata) allow for the carbon dioxide to enter the leaves. Point to photo on Smartboard

15. 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!

16. Look inside biochamber- what part of the plant is in there? Leaves

17. Leaves have water, there is CO2, and light- what are the leaves going to produce? Look at equation: sugar and O2

18. 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:

1. Before you collect data, what do we need to do? Make prediction

2. 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.

3. Ask students to discuss with their lab partner and circle their prediction.

4. 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.

5. Now we are ready to start collecting the data using the hand held computer- LabQuest/

6. Tell the students how to turn on the Lab Quest by pushing the power button on the upper left side. See red arrow below.

7. After the Lab Quest turns on, they should see two sensors on the screen Oxygen and Carbon dioxide.

8. Ask what the units are for CO2- ppm parts per million.

9. Ask students what the units are of O2? %

10. Explain that they are going to change units to ppt.

11. Ask one student touch the oxygen screen. They should see "change units." Have students change the units to ppt (parts per thousand).

12. 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.

13. Ask students to look at bottom right of screen. Collecting time- what does “s” stand for? Seconds

14. Explain students will collect data for 3 minutes. How many seconds are in three minutes? 180 - They need to stop collecting data at 180 seconds. They stop data by pushing the red square at the bottom left corner.

15. While the students are collecting, have them watch the numbers for Oxygen and Carbon Dioxide. What is happening to them? CO2 decreasing, O2 increasing

16. After three minutes, have the students push the red square to stop collecting data. A graph will display on the screen.

17. Ask students to record their data on their data sheet. Record CO2 first, then O2. They don’t have to be exact, just to show the trend.

18. Display the sample Vernier graph results on the SMART board. Do the students’ results look similar?

19. Let’s analyze the data. Graphs tell a story. Look at CO2 line- what is happening to CO2 over time? Decreasing

20. Did someone open up lid and remove CO2? No Where did it go? Inside the leaves. Show picture of stomata on board.

21. Now let’s analyze O2 line- what is happening to O2 over time? Increasing

22. Did someone open up lid and add O2? No Where did it come from? Inside the leaves, Show picture of stomata on board.

23. Explain that many times scientists cannot see what they are studying so they need tools to help them.

24. Ask students to show how many times scientists run a test or trial in science? 3

25. Explain that they are going to run another trial. Have the students touch the green arrow again to conduct another run. At the popup screen, they will select “discard data.” How long are they going to collect data for? 180 seconds

26. Have students collect data for another three minutes and observe the numbers for oxygen and carbon dioxide.

27. Play the photosynthesis song on Smartboard as students are waiting.

28. After three minutes, have students push the red square to stop the data collection.

29. Analyze the results whole group by asking students to give a thumbs up to show “increase” and thumbs down to show “decrease.” Ask, what happened to the CO2? thumbs down What happened to the Oxygen? thumbs up

30. Repeat a third trial if time allows.

31. Have students turn off their labquests and circle their conclusion.

32. Teacher should carefully lift off the lid to prevent condensation between classes and turn off light.

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

4. 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.

6. What could be the IV? types of leaves, parts of plants, amount of light etc..

Extensions/Modifications:

1. If you don’t have the entire 45 minutes, you can omit Part 1 and just have the students do the photosynthesis activity.

2. 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 http://www.doe.virginia.gov/testing/sol/standards_docs/science/2010/lesson_plans/index.shtml

References:

Verneir website with tutorials for using labquests and probeshttp://www.vernier.com

Prince William County Public Schools: Science Investigations

Photosynthesis Investigation SOL 4.4c

Prince William County Public Schools: Science Investigations