Assignment 2 - Data Logger (Photosynthesis, Oxygen and Carbon Dioxide)

1.0       WHAT IS DATA LOGGER?

A set of data logger consists of a data logging interface and sensors. There is a range of sensors which convert physical parameters, e.g. temperature, pressure, humidity into digital signals. Data logging interfaces convert, process and transfer the signals to the computer. Some data logging interfaces can also store data temporarily. Most data loggers are supplied with computer software which can display the collected data graphically on a computer screen and process the data for further analysis.

A sensor is a device that senses surrounding data which is then recorded by a data logger. Generally, four or more sensors are capable of being connected to a data logger, depending on the model. There are over 40 different sensors available, including light, temperature, pressure, conductivity, motion, humidity, oxygen, carbon dioxide, pH, voltage, wind speed, and wind chill.

2.0    INTRODUCTION (Photosynthesis, Oxygen and Carbon Dioxide)

Plants make sugar, storing the energy of the sun into chemical energy by the process of photosynthesis. Photosynthesis is the process whereby the radiant energy of the sun is converted into chemical potential energy of organic molecules. The process of photosynthesis involves the use of light energy to convert carbon dioxide and water into sugar, oxygen and other organic compounds. This process is often summarized by the following reaction:

6 H₂O + 6 CO₂ + light energy → C₆H₁₂O₆ + 6 O₂

Cellular respiration refers to the process of converting the chemical energy of organic molecules

into a form immediately usable by organisms. Glucose may be oxidized completely if sufficient

oxygen is available by the following equation:

C₆H₁₂O₆ + 6 O₂ → 6 H₂O + 6 CO₂ + energy

All organisms including plants and animals, oxidize glucose for energy. Often, this energy is

used to convert ADP and phosphate into ATP.

               For this experiment, were going to detect what is the gas produced by the plant as the result of photosynthesis and what is the amount of gas produced during that time using the gas sensor. Two types of gas sensor that is oxygen gas sensor and carbon dioxide gas sensor will be used.

            The oxygen and carbon dioxide sensors will be used to measure any change in the concentration of those gases in the presence of a plant specimen. The sensors are connected to a hub called Lab Quest Mini that connects to a computer and allows you to see and record in real time the measurement of oxygen in the chamber. This apparatus is sensitive and expensive, so please use caution when experimenting. The software you will use with this set up is called Lab Pro/CBL 2 and it will record data and create a graph while you experiment.

            The oxygen sensor continually measures the oxygen concentration using a lead anode, a gold cathode, and an electrolytic solution which carries a current produced in proportion to the oxygen concentration by the reduction of the oxygen molecules. The oxygen sensor must be kept upright or it will not work properly and could be damaged. It is the vertical sensor seen in the photo of your apparatus.

            The carbon dioxide sensor is the horizontal sensor and uses infra‐red emission to measure the gas concentration in the tube between one end of the sensor tube where the beam is generated and the other end where it is measured. The amount of infra‐red reaching the sensor at the end of the tube is inversely proportional to the concentration of carbon dioxide because it is absorbed by carbon dioxide.

3.1       PROBLEM STATEMENT

1)      What gas will be released and consumed for photosynthesis?

2)      What is the type of gas sensor that needs to be used for this photosynthesis gas experiment?

3)      How to set up and connect the gas sensor to the computer correctly for this experiment?

4)      What is the correct way to use the sensor in order to measure the amount of gas that is released and consumed by a plant during photosynthesis more accurately?

5)      What are the precaution steps that need to be taken while using the sensor?

6)      What is the correct and precise method to take the reading from the sensor?

7)      How to calculate the rate of respiration/photosynthesis from the graph displayed on the monitor?

8)      How the applications of the gas sensor help you to obtain result that is more accurate?

4.0       EMPOWERING (Experiment)

4.1       Objectives:

In this experiment, you will:

1.      Use an O₂ Gas Sensor to measure the amount of oxygen gas consumed or produced by a plant during respiration and photosynthesis.

2.      Use a CO₂ Gas Sensor to measure the amount of carbon dioxide consumed or produced by a plant during respiration and photosynthesis.

3.      Determine the rate of respiration and photosynthesis of a plant.

4.2       Materials:

-          Lab Pro or CBL 2 interface                      -           250 mL respiration chamber

-          TI Graphing Calculator                             -           Data Mate program

-          Forceps                                                      -           Vernier O₂ Gas Sensor

-          Vernier CO₂ Gas Sensor                           -           CO₂ – O₂ Tee

-          Plant leaves                                               -           500 mL tissue culture flask

-          Lamp                                                         -           Aluminium foil

4.3       Procedures:

1.      Plug the O₂ Gas Sensor into Channel 1 and the CO₂ Gas Sensor into Channel 2 of the Lab Pro or CBL 2 interface. Use the link cable to connect the TI Graphing Calculator to the interface. Firmly press in the cable ends.

2.      Turn on the calculator and start the DATAMATE program. Press CLEAR to reset the program.

3.       Set up the calculator and interface for an O₂ Gas Sensor and CO₂ Gas Sensor.

a)      Select SETUP from the main screen.

b)      If the calculator displays an O₂ Gas Sensor in CH1 and a CO₂ Gas Sensor in CH2, proceed directly to Step 4. If it does not, continue with this step to set up your sensors manually.

c)      Press ENTER to select CH1.

d)     Select OXYGEN GAS from the SELECT SENSOR menu.

e)      Select parts per thousand (PPT) as the unit.

f)       Press once and then press ENTER to select CH2.

g)      Select CO₂ GAS from the SELECT SENSOR menu.

h)      Select parts per thousand (PPT) as the unit.

4.      Set up the data-collection mode.

a)      To select MODE, press (the up arrow key) twice and press ENTER.

b)      Select TIME GRAPH from the SELECT MODE menu.

c)      Select CHANGE TIME SETTINGS from the TIME GRAPH SETTINGS menu.

d)     Enter “15” as the time between samples in seconds.

e)      Enter “40” as the number of samples (data will be collected for 10 minutes).

f)       Select OK twice to return to the main screen.

5.      Obtain several leaves from the resource table and blot them dry, if damp, between two pieces of paper towel.

6.      Place the leaves into the respiration chamber using forceps if necessary. Wrap the respiration chamber in aluminum foil so that no light reaches the leaves.

7.      Insert the CO₂–O₂ Tee into the neck of the respiration chamber. Place the O₂ Gas Sensor into the CO₂–O₂ Tee as shown in Figure 1. Insert the sensor snugly into the Tee. The O₂ Gas Sensor should remain vertical throughout the experiment. Place the CO₂ Gas Sensor into the Tee directly across from the respiration chamber as shown in Figure 1. Gently twist the stopper on the shaft of the CO₂ Gas Sensor into the chamber opening. Does not twist the shaft of the CO₂ Gas Sensor or you may damage it.

8.      Wait two minutes, and then select START to begin data collection. Data will be collected for 10 minutes.

9.      When data collection has finished, remove the aluminum foil from around the respiration chamber.

10.  Fill the tissue culture flask with water and place it between the lamp and the respiration chamber. The flask will act as a heat shield to protect the plant leaves.

11.  Turn the lamp on. Place the lamp as close to the leaves as reasonable. Do not let the lamp touch the tissue culture flask.

12.  Press ENTER to view the graph of O₂ GAS VS. TIME. Sketch a copy of your graph in the Graph section below. When finished, press ENTER to return to the graph menu. Press once, and then press ENTER to view the graph of CO₂ GAS VS. TIME. Sketch a copy of your graph in the Graph section below. When finished, press ENTER to return to the graph menu. Select MAIN SCREEN from the graph menu.

        

13.  Perform a linear regression to calculate the rate of respiration/photosynthesis.

a)      Select ANALYZE from the main screen.

b)      Select CURVE FIT from the ANALYZE OPTIONS menu.

c)      Select LINEAR (CH 1 VS TIME) from the CURVE FIT menu.

d)     The linear-regression statistics for these two lists are displayed for the equation in the form: Y=A∗X+B

e)      Enter the value of the slope, A as the rate of respiration/photosynthesis in Table 1.

f)       Press ENTER to view a graph of the data and the regression line.

g)      Press ENTER to return to the ANALYZE menu.

h)      Repeat Steps 13b – 13g to calculate the respiration and photosynthesis rate using the data from the CO₂ Gas Sensor (CH2 VS TIME).

i)        Select RETURN TO MAIN SCREEN from the ANALYZE menu.

14.  Repeat Steps 8 – 13 to collect data with the plant exposed to light.

15.  Remove the plant leaves from the respiration chamber using forceps if necessary. Clean and dry the respiration chamber.

4.4       Result:

Leaves	O2 rate of production/consumption (ppt/s)	CO2 rate of production/consumption (ppt/s)
In the dark	-0.0023	0.00065
In the light	0.0045	-0.00126

Graphs:

4.5       Discussions:

1.      Were either of the rate values for CO₂ a positive number? If so, what is the biological significance of this?

The CO₂ rate value for leaves in the dark was a positive number. The biological significance of this is that CO₂ is produced during respiration. This causes the concentration of CO₂ to increase, as sugar is oxidized and broken into CO₂, water and energy.

2.      Were either of the rate values for O₂ a negative number? If so, what is the biological significance of this?

The O₂ rate value for leaves in the dark was a negative number. The biological significance of this is that O₂ is consumed during cellular respiration. This causes the concentration of O₂ to decrease as glucose is oxidized for energy.

3.      Do you have evidence that cellular respiration occurred in leaves? Explain.

Yes, cellular respiration occurred in leaves since O₂ decreased when leaves were in the dark and photosynthesis was not possible.

4.      Do you have evidence that photosynthesis occurred in leaves? Explain.

Yes, photosynthesis occurred in leaves since O₂ increased when leaves were exposed to the light.

5.      List five factors that might influence the rate of oxygen production or consumption in leaves. Explain how you think each will affect the rate?

a) A greater number of leaves should increase the rate since there are more chloroplasts to undergo photosynthesis and more cells to require energy through cellular respiration.

b)    A greater light intensity will increase the rate of photosynthesis. It may not affect the rate of cellular respiration.

c)    A cooler room may decrease both rates, as cellular metabolism decreases in cooler weather.

d)  If the plants overheat due to the heat from the lamp, they may wilt and stop functioning. This will decrease all rates.

e) If there too many leaves, diffusion may be restricted and prevent accurate readings. This may apparently decrease both rates.

5.0       ENHANCING

Oxygen is a chemical element with symbol O and atomic number 8. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colourless, odourless, tasteless diatomic gas with the formula O₂. This substance is an important part of the atmosphere and is necessary to sustain most terrestrial life. Without oxygen gas, human and animals cannot life in this planet. The uses of the oxygen gas is divided into two group, first is directly use to produce the new substance that combine with the oxygen gas that can be used in daily life and second group is indirectly use which we store the oxygen gas and use it when we need it for other purpose.

Firstly are the direct uses, human, animals and other organism need oxygen gas for the respiration process to life. Without oxygen gas, human, animals and other microorganism will die. Other, the oxygen is needed to combine with another elements to be other compound such water (H₂O), the combination of two molecule hydrogen and one molecule of oxygen. The combustion also needs an oxygen gas to occur. The combustion process will not happen without oxygen gas. For example, the combustion in engine will move the piston and make the vehicles such as car, bus, ship and aircraft to move.

Secondly are the indirect uses. These mean that the oxygen gas was stored at some cylindrical bottle or tank for other purpose. The application of the oxygen gas that stored is used for diving, welding, cutting of metal, aircraft and medical. The highly technology was used such as the gas compressors, oxygen sensor, oxygen concentrator and the compressors oxygen cylinder was used to store the oxygen gas. This cylindrical oxygen gas only can be used when it is needed. In diving activities, the divers will use the oxygen gas cylinder to support them with oxygen when inside the deep sea.

For welding, the oxygen gas was needed to support and give enough amount of oxygen gas for combustion process in high temperature to melt the metal used. Other, in the aircraft, the oxygen gas tank and the oxygen sensor is important during emergency and to detect the concentration of oxygen gas inside the aircraft. When the aircraft is fly too high, the concentration of nitrogen gas is higher the oxygen gas, therefore it will caused the passengers difficult to breath, so the pilot need to supply them with the oxygen gas to help them to breathe through the funnel oxygen gas.

Besides that, the major uses of the cylinder bottle or tank oxygen gas in medical application. When the people are sick, their ability to breath is limited, therefore we need to supply the oxygen gas to them by using the specific mask. Oxygen masks are administered medically for patients in the hospital. Oxygen masks are also used in oxygen therapy. They are used for those suffering from pulmonary conditions or disease. The other form of oxygen element in medical is liquid oxygen which is stored in cryogenic (cold) storage containers. Liquid oxygen is used to produce vitamin supplements. Oxygen travels with the supplement to the digestive tract to detoxify the body. Sometimes liquid oxygen comes in the form of medical spray. It will help heal minor cuts, wounds or abrasions.

Therefore, the oxygen gas is very important in our daily life not just for breathe, but can be used to make our work easily. Besides, the oxygen gas also important in producing some other material from combining with the other element or material, industrial, combustion, medical, research, astronaut at outer space, and diving.

Picture 1: Mini Oxygen gas cylinder for medic

         Picture 2: Oxygen gas cylinder for diving              

  
  

6.0       CONCLUSION

Photosynthesis (the process by which organisms convert light from the sun into glucose sugar molecules for energy) was occurring by measuring the level of oxygen given off as a waste product by the Elodea aquatic plant(plant leaves) when submerged in water and treated with a strong light source.

An oxygen and carbon dioxide sensor connected to a data logger. As the photosynthesis and respiration reaction occurred, the data fed into a computer. Then, data analysis will conducted by using a program to determine the minimum and maximum dissolved oxygen and carbon dioxide concentrations released into the water over the course of the experiment. This approach allowed us to understand more clearly about the relationship among photosynthesis, cellular respiration and energy flows through living systems.