Data Logger

INFORMATION AND COMMUNICATION TECHNOLOGY IN BIOLOGY

(SBI3013)

ASSIGNMENT 2: DATA LOGGING

TITLE: EFFECT OF LIGHT INTENSITY ON THE RATE OF PHOTOSYNTHESIS

(USING A LIGHT SENSOR)

LECTURER : EN. AZMI BIN IBRAHIM

GROUP MEMBERS : 1) NUR SYAFINAS BT ASLAN (D20141066905)

2) NUR INSYIRAH BT TOKIJOH (D20141066923)

INTRODUCTION:

Photosynthesis is the process of producing food in form of glucose from the reaction

between carbon dioxide and water which carried out by the green plants or some of the

organisms in the present of sunlight. This process in undergo in plants and generally it

involves the green pigment in the leaf called chlorophyll and the product that will produce are

glucose (for plant food and oxygen) as a by-product. Now, the application of data logger in

this process will shows the effect on light and temperature for the rate of photosynthesis. This

set of data logger will consists of a data logging interface and a light sensor. The sensor will

take the measurement of the light during the process of photosynthesis. Then, most of this

data loggers are connected and supplies with the computer software so that data can display

directly during the experiment. The advantages that having this data logger are the practical

work can be conducted easily and the understanding about photosynthesis is better because

the students can learn the simplest way how to conduct an experiment and to get the result.

However, it will course some students will having a difficulty in relating the science concepts

to the microscopic and symbolic system representations.

ENGAGE:

Engage is a way to involve the students in the activity that the teacher make. The activity are

such like set induction, practical or a presentation about some topic.

Source from http://wiki.bhikku.net/pmwiki.php/Photosynthesis-TheProcess

Sooksalee, S., Tho. J. and Britton, N. (2008), demonstrated this experiment to see

how the light will influence the rate of photosynthesis on the Elodea sp. Based on this

experiment, they concluded that the student should be expected to understand the process of

photosynthesis that happen, the reactants that are involve and the product that will produce.

Moreover, the students should remember or recall the reaction and develop the reaction into a

symbol of equation. At what levels of light that the rate of reaction will be affected?

Photosynthesis known as the process of making glucose for the plants. This process

involve the present of sunlight or light and the organelle in the leaves. The energy from the

sunlight are converted into the chemical energy in order to produce a glucose and oxygen. In

addition, the student also be able to write the equation of photosynthesis. Do the equation will

contribute to the understanding of the students towards photosynthesis process. The following

equation is the reaction of photosynthesis:

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

Problem statement:

1) What is the effect of light on the rate of photosynthesis?

2) What is the relationship between light and rate of photosynthesis?

3) What is the product of photosynthesis process?

4) What is the correct way to use light sensor?

Objectives:

1. To study the effect of light in the rate of photosynthesis.

2. To determine the relationship between light and the rate of photosynthesis of Elodea

sp.

3. To know how to set up the apparatus and connect the light sensor to the software in a

computer for the photosynthesis process.

4. To conduct the procedure to use the light sensor for the measurement of the gas that

release.

5. To identified the by-product of the photosynthesis process.

EMPOWER

Material and apparatus

Beaker, 600 cm3

Metre ruler

Elodea/oxygenating pond plant

Scissors

Forceps

Electric lamp

Retort stand

Stopwatch

Light sensor

Procedure

1. A flask was filled with water and Elodea was placed inside it.

2. The oxygen sensor was calibrated according to the user’s manual

3. The dissolved oxygen sensor was placed into the flask.

4. Light sensor was used to detect the change in light intensity.

5. The data logger was started to detect the changes in light intensity and dissolved oxygen

content for a period of time (Fig.1).

6. Data logger was stopped after sufficient amount of data is collected. Computer software

was used to plot the data in a suitable form (Fig.2).

Result

Light Intensity (units) Rate of photosynthesis (number of bubbles per minute)

1 3

3 11

5 23

8 44

10 44

12 44

Graph

Rate of photosynthesis

Rate of photosynthesis become constant

Light intensity

Discussion

1. Does light intensity affect the rate of photosynthesis in Elodea plants?

Yes, light intensity does affect the rate of photosynthesis.   Too much light may

cause plants to "burn out" while too little light will not provide enough light for

optimal photosynthesis activity.

2. Describe the effect of light intensity on the rate of photosynthesis.

At low light intensities, as light intensity increases, the rate of the light-

dependent reaction, and therefore photosynthesis generally, increases

proportionately (straight line relationship). The more photons of light that fall

on a leaf, the greater the number of chlorophyll molecules that are ionised and

the more ATP and NADPH are generated. Light dependent reactions use light

energy and so are not affected by changes in temperature. As light intensity is

increased further, however, the rate of photosynthesis is eventually limited by

some other factor. So the rate plateaus. At very high light intensity, chlorophyll

may be damaged and the rate drops steeply (not shown in the graph).

3. Why does the rate of photosynthesis become constant after light intensity reaches a

certain level?

In a process like photosynthesis which is affected by more than one factor, its

rate is limited by the factor which is closest to its minimum value. So at any point

in time if one of the three factors is in low supply, this factor will be the limiting

factor. Only a change to the limiting factor will increase or decrease the rate of

photosynthesis. Changing the other two will have no effect.

4. What are the other factors that can affect the rate of photosynthesis?

The other main things affecting the rate of photosynthesis are temperature and

carbon dioxide. The higher the temperature then typically the greater the rate of

photosynthesis, photosynthesis is a chemical reaction and the rate of most

chemical reactions increases with temperature. However, for photosynthesis at

temperatures above 40°C the rate slows down. This is because the enzymes

involved in the chemical reactions of photosynthesis are temperature sensitive

and destroyed at higher temperatures.

Carbon dioxide is used to make sugar in the photosynthesis reaction. The

concentration of carbon dioxide in the Earth’s atmosphere varies between 0.03%

and 0.04%. An increase in the concentration of carbon dioxide gives an increase

in the rate of photosynthesis. It is difficult to do this out in the open air but is

possible in a greenhouse.

ENHANCE

1. Eye laser surgery (LASIK)

This highly specialized laser uses a cool ultraviolet light beam to remove

("ablate") microscopic amounts of tissue from the cornea to reshape it so it more

accurately focuses light on the retina for improved vision.

2. Biological clock

Biological clocks are a way for organisms to track the passage of time so that they

can anticipate and adapt to changing environmental conditions e.g. plants

anticipating the day so that they can prepare their photosynthetic apparatus in

time. This altered (entrained) by light levels and changing lengths of photoperiod.

This allows an organism to anticipate seasonal changes and adjust to changing day

lengths.

3. Solar energy

Solar energy used to generate electricity and produce hot water. Solar cells are

devices that collect and convert light energy directly into electrical energy. Solar

energy is a renewable energy resource and there are no fuel costs. No harmful

polluting gases are produced.

4. Process of seeing and perceiving

The bottom line is: without light, there would be no sight. The visual ability of

humans and other animals is the result of the complex interaction of light, eyes

and brain. We are able to see because light from an object can move through space

and reach our eyes. Once light reaches our eyes, signals are sent to our brain, and

our brain deciphers the information in order to detect the appearance, location and

movement of the objects we are sighting at.

EXTENSION

Measuring photosynthesis via the uptake of carbon dioxide

1. Using 'immobilised algae' - It's easy and accurate to measure the rate of

photosynthesis and respiration using immobilised algae in hydrogen carbonate

indicator solution - known as the 'algal balls' technique.

2. Using an IRGA - Uptake of CO2 can be measured with the means of an IRGA (Infra-

Red Gas Analyser) which can compare the CO2 concentration in gas passing into a

chamber surrounding a leaf/plant and the CO2 leaving the chamber.

REFERENCE:

Sooksalee, S., Tho, J., and Britton, N., (2008). Energy flow: A scheme of work. Retrieved

from http://wiki.bhikku.net/pmwiki.php/Photosynthesis-TheProcess

Monitoring of the rate of photosynthesis by using data logger. Retrieved on 7th Oct 2015 from

http://cd1.edb.hkedcity.net/cd/science/biology/resources/l&t2/practical/Practical-

32.pdf

Investigating factors affecting the rate of photosynthesis. Retrieved on 18th Oct 2015 from

http://www.nuffieldfoundation.org/practical-biology/investigating-factors-affecting-

rate-photosynthesis

Light-real life application: colours. Retrieved on 17th Oct 2015 from

http://www.scienceclarified.com/everyday/Real-Life-Physics-Vol-3-Biology-Vol-1/

Light-Real-life-applications.html