Group+12

THE GARDEN OF TIME BY GROUP 12 (Jennie Novita, Kimiko Widjaja, Karina Desiree, Jeffrey Koby, Ferris Arrafi, Brian Pratadaya) __Research Question:__ How does the time of the day affect activities in the artificial pond? __Background:__ Photosynthesis is essential for plant to grow. Photosynthesis can be defined as a chemical reaction at which plants produce their own organic substance using light energy and simple inorganic substance. Photosynthesis can be presented in the following equation: CO2 + H2O+ Light <--->C6H12O6 + O2  This experiment will explore the four factors; that affect photosynthesis reaction, which are carbon dioxide uptake, light intensity, temperature and production of oxygen gas. As these factors corresponds to each other to produce the product and affects its rate. The plant that we’ll be using is an aquatic plant, Elodea. It is the most common type of plant used in photosynthesis experiments, as it is easy to see the changes and are able to photosynthesize quiet fast. This plant can get its source of reactants for photosynthesis to occur through water and they can grew even when already cut from its roots. __Aim__: __Hypothesis:__ __Variables:__ Using a stopwatch did this and a clock to know what time is it. By making it every 30 minutes we could also know the range and the different the dependent variable can make to this time of the day in a quite short time. It is by a stopwatch that we were able to make it constant to 30 minutes. Although at first we were actually going to make it into 1 hour but there were not enough time and changed it to 30 minutes. As in 30 minutes the plant could also still photosynthesize and we can observe the changes. These are our dependent variable as it is what our aim is to find out these changes of photosynthesis as the time of the day changes. It is also to find out how these 4 variables can affect each other and relate to the independent variable. We used dissolve oxygen (to measure dissolve O2), pH sensor (to measure carbon dioxide uptake), lux meter (to measure the light intensity) and also thermometer to measure these variables as to make it accurate and for a sufficient data. I. Length of Elodea (20 centimeters): A ruler was used to measure the length of Elodea. The length of Elodea has to be kept constant so the CO2 and O2 produced in the distilled water can be the same for all the photosynthesis unless the time of the day has affected it. This is so that we could see how the independent variable can affect the rate of photosynthesis of Elodea. We keep it constant by measuring the Elodea (20cm) by using a ruler, if it’s too long we will cut itusing scissors as not to destroy the plant, if its too short we will add another leaf and then insert it to the water. We choose 20cm Elodea plant as it was enough to produce CO2 and O2 in just 30 minutes and also because too much of this plant can reduce the volume of distilled water, we don’t want to big of a data but just sufficient enough to be recorded by the data logger. It was also because the end of the probe can’t touch the plant as it the plant was too much we couldn’t keep the plant in the bottom and it could touch the probe, breaking the machine. As if it was too little the data would be too small to measure or the rate of photosynthesis could be too slow. This is also a reason why it needs to be constant because a vary of elodea yield could vary the rate of reaction which then wouldn’t make it trials. II. Volume of distilled water (600ml) used for photosynthesis reaction of Elodea: The volume of distilled water were 600ml as we already measured in this volume the Elodea will be covered and so were the flask, this is to make sure that there’s no other gas that can interrupt with the process. As this experiment is done in a closed space for us to be able to measure the changes of gases inside. If it was open other gases might able to get in and change the result. We keep the volume of distilled water as not to provide too much water for the photosynthesis and to only measure how the light intensity, temperature (time of the day) affects the rate of photosynthesis, which produces CO2 and O2 in the water. As the volume of distilled water could affect the photosynthesis rate which is something that we do notpursue. We keep this constant by measuring the distilled water in a measuring cylinder then insert it to the Erlenmeyer flask. III. Molarity of Sodium Bicarbonate/ NaHCO3 (0.2%): The molarity of Sodium Bicarbonate needs to be constant as this could affect the rate of photosynthesis. It was kept 0.2% as from our research, we found out that Elodea works best in this molarity. As sodium bicarbonate can increase the yield of carbon dioxide in the water for photosynthesis to occur and this amount can already make photosynthesis to occur for Elodea. If we did not make it constant among the trials this could vary our result and the result wouldn’t be accurate as what our aim want to investigate. This is because our dependent is the C02 and the molarity of sodium bicarbonate can increase the CO2 concentration that will affect out result if it is varied. We kept this constant by first measuring the sodium bicarbonate in a beaker with measuring scale up to 1.2g and then mix it with 600ml of water so that it could be 0.2%. Which then used for the water photosynthesis. IV. Calibration time of dissolve oxygen sensor and pH sensor, which is needs to be done in every trial to make the probes neutral again into its original state. If this is not done the data that is recorded mightn’t be accurate since the start is doesn’t start from normal and the data would be too varied. This is kept constant for every trial to make the data fair and also to find out the real changes or the initial measurement. As if it was not done the probes accuracy will be lowered down and the initial data would also be wrong. Using a data logger to calibrate does this to make the accuracy (pH sensor is calibrated until it reaches 7pH as it is the normal pH for water and dissolve oxygen at 4. However the initial of dissolve oxygen is not really important, as we only want to find out the changes). We use buffer solution for a pH sensor and also distilled water for dissolve oxygen to calibrate, things that would react to the probes to make it neutral, does it. V. Calibration time (20 seconds) We keep the calibration time constant as to not make the calibration overdue and waste our time. It is 20s because the usual time to calibrate probes to reach their neutral time is in this range of time. We made sure it is the same for all trials since we want to make the situation the same and to see the changes as not to make the data varied. We were able to do this by seeing the Data Logger as we calibrate as it reach to 7pH and count it to 20s with a stopwatch. VI. Time range for every trial in which rate of photosynthesis is measured (30 minutes) The time range indeed needs to be constant, as we want to find the changes during the time of day and to make it in trials it is 30 minutes. It was also to make the trial to have the same observation or result that we can compare because this was constant.We made it into 30 minutes was because the photosynthesis process can already be seen and recorded in just 30 minutes and we didn’t have enough time for the experiment to have all 9 trials in one day. This was kept constant by using a stopwatch as our timer and started it right when we pressed start in the data logger for data. VII. pH of buffer used to calibrate pH sensor (pH 7) The pH of buffer used is 7 as it is neutral and in this pH the solution is neither acid nor base. Therefore we can make the pH sensor to be neutral and are more accurate to sense the initial pH when we insert it that is not disturb by other pH solutions. This could make our data more accurate and provide a good judgment. It was easy to keep this constant as we could just easily find this buffer in the school that is already produced its pH to 7. However we needed to keep it closed in an aluminum foil to make sure that it isn’t contaminated or reacted by the air, bacteria, etc. VIII. Location of experiment (garden) This is needed to be constant as the location can affect our dependent variables such as the light intensity and temperature of the place which can make our data vary and unable to reach our investigation. We choose the garden of Binus as it provides a good sunlight and are suitable for us to use as no many people come there and we could focus on our experiment. The place also provides us with electricity plug that we could connect our probes and data logger to record the data. __Materials__: __Procedure:__ __Raw Data__ __Table 1:__ The pH of water (pH) during photosynthesis of 20 cm Elodea when it is submerged with distilled water and 0.2% Sodium Bicarbonate and sealed. pH is measured using pH sensor that is connected to a data logger. As we can see from the table that we have finalize from the graph in the data logger. The final pH is highest in the morning during trial 1, that we can predict that there is a faster rate of photosynthesis in just 30 minutes. This also means that the CO2 is also really low in this time of the day because the pH is the highest and as CO2 dissolves (mixed in water) it is forming carbonic acid. However, during noon trial 3 it is the lowest and if we estimate it by looking the data at noon, it has the lowest pH, which means the rate of photosynthesis, is low (decrease). __Table 2__: The concentration of Oxygen gas (mg/L) dissolved in water during photosynthesis of 20 cm Elodea when it is submerged with distilled water and 0.2% Sodium Bicarbonate and sealed. Dissolved oxygen is measured using dissolved oxygen sensor that is connected to a data logger. As we can see from the graph, the dissolved oxygen gas production is the highest in the morning during the first trial. This gives us a clue that the highest rate of photosynthesis of Elodea might happen in the morning. On the other hand, the lowest dissolved oxygen gas production observed is at noon.
 * Biology: To investigate the rate of photosynthesis of Elodea (a type of aquatic plant) by measuring the production of oxygen gas dissolves in water (600ml) every 30 minutes.
 * Chemistry: To investigate the CO2 uptake during Elodea (a type of aquatic plant) photosynthesis by measuring the change of pH in water in every 30 minutes.
 * Physics: To investigate how the light intensity and temperature difference during the time of the day affect the rate of photosynthesis of Elodea (a type of aquatic plant).
 * Biology: Oxygen gas production is the product of photosynthesis reaction. It is measured using dissolve oxygen probe, as the plant used will be Elodea, an aquatic plant.We think, the highest oxygen gas production will be during noon because at noon, there will be more light intensity which will increase the temperature and increase the product of oxygen gas produce. As these factors are the one that triggers the production of oxygen gas during photosynthesis. The rise of the temperature could also mean that the light intensity is increased. Therefore, the more light intensity the faster the production of this can happen and will give rise to a bigger yield of oxygen gas and faster rate. As time went on the DO should be rising and is biggest during noon.
 * Chemistry:Carbon dioxide gas is one of the reactants for photosynthesis reaction. We predicted as the photosynthesis is happening the pH would go up as the carbon dioxide are decreasing and this can be seen in the noon better, the rate at which carbon dioxide is changed will be faster in this time of the day. This is because as carbon dioxide increased or mixed in water it would form carbonic acid that would lower down the pH of the water. Which means when it is used up or dissolves then the water pH would rise. As during noon there will be less sunlight, which means less light intensity and the rate at which carbon dioxide will be used is increased. The time for the reaction will decrease. This will result to a fast change of pH duringnoon. The pH of water will be the go down then constant as the amount of CO2in each trial are constant (it cannot go further as to change the pH). This happens because of a reverse reaction, when the light intensity decrease the equilibrium position would shift to the left to increase the light (product) that also results in an increase of CO2and water according to LCP. However when the light intensity increase, during noon, the yield of CO2 will decrease as the equilibrium position would shift to the right and form oxygen lowering the CO2and increasing the water pH. This means the pH would be highest in the noon and lowest during afternoon.
 * Physics: With the increase of light intensity acted on the surface of the flask, there will be an increase of temperature to the flask, thus showing that the plant has a light source for photosynthesis.
 * Independent: time of day (every 30 minutes)
 * Dependent: oxygen gas production in water, carbon dioxide uptake, light intensity and temperature.
 * Controlled:
 * 3 of 500 ml Erlenmeyer flask
 * 1 of 100 ml measuring cylinder
 * Stopwatch
 * Elodea plants (__+__180 cm)
 * Data logger (Pasco)
 * Stopwatch
 * pH sensor
 * Lab thermometer
 * Dissolved Oxygen sensor
 * Luxmeter
 * Distilled water
 * Sodium bicarbonate (NaHCO3)
 * 1 Spatula
 * Buffer solution (7 pH)
 * 3 of 100 ml beaker
 * Scissor
 * 15 cm ruler
 * Napkin
 * Plasticine (Oil-based clay)
 * All materials have been gathered prior to the experiment day
 * The Erlenmeyer flask is filled with 600ml of distilled water
 * Sodium Bicarbonate (NaHCO3) has been measured as much as 1.2 grams
 * The Elodea (a type of aquatic plant) has been cut as much as 20cm and then divided again into 2 cuts; 10cm each
 * The Elodea and NaHCO3of 0.2M has been combined inside the Erlenmeyer flask along with the distilled water and stirred with a spatula
 * The pH sensor and the D.O (Dissolved Oxygen) has been connected to a data logger that has been connected to a power source
 * The pH sensor has been calibrated using a buffer that uses a pH concentration of 7 for 20 seconds using a stopwatch. After using the buffer solution it was covered by aluminum foil.
 * The D.O (Dissolved Oxygen) has been calibrated with distilled water for 20 seconds
 * The pH sensor and the D.O; along with the thermometer has been inserted inside the Erlenmeyer flask and sealed with plasticine (oil-based clay that will never dry)
 * Timer (stopwatch) has been set for 30 minutes
 * Changes of the pH concentration, temperature, and D.O concentration have been observed and so were the reaction.
 * The Luxmeter (Light meter) has been activated.
 * The amount of light has been measured every 30 minutes with the Luxmeter.
 * Procedures have been repeated for 3 trials in 3 different time of the day for 30 minutes every procedure.
 * Time of Day ||  Hours  ||||  The pH of water during photosynthesis of Elodea in a closed system (pH)(__+__5x10-5pH)  ||
 * ^  ||^   ||  Initial  ||  Final  ||
 * Morning ||  8.30-9.00  ||  4.2  ||  4.8  ||
 * ^  ||  10.00-10.30  ||  3.6  ||  4.7  ||
 * ^  ||  10.30-11.00  ||  4.3  ||  4.6  ||
 * Noon ||  11.30-12.00  ||  4.1  ||  4.5  ||
 * ^  ||  12.30-1.00  ||  4.2  ||  4.5  ||
 * ^  ||  1.00-1.30  ||  3.1  ||  3.5  ||
 * Afternoon ||  1.30-2.00  ||  3.4  ||  4.5  ||
 * ^  ||  2.00-2.30  ||  4.1  ||  4.6  ||
 * ^  ||  2.30-3.00  ||  3.9  ||  4.3  ||
 * Time of Day ||  Hours  ||||  Concentration of Oxygen Gas dissolved in water during photosynthesis of Elodea in a closed system (mg/L)(__+__5x10-5 mg/L)  ||
 * ^  ||^   ||  Initial  ||  Final  ||
 * Morning ||  8.30-9.00  ||  1.8  ||  2.4  ||
 * ^  ||  10.00-10.30  ||  1.4  ||  1.6  ||
 * ^  ||  10.30-11.00  ||  0.0  ||  0.3  ||
 * Noon ||  11.30-12.00  ||  1.0  ||  1.2  ||
 * ^  ||  12.30-1.00  ||  0.9  ||  1.1  ||
 * ^  ||  1.00-1.30  ||  1.7  ||  2.0  ||
 * Afternoon ||  1.30-2.00  ||  1.4  ||  2.6  ||
 * ^  ||  2.00-2.30  ||  1.3  ||  1.5  ||
 * ^  ||  2.30-3.00  ||  1.2  ||  1.7  ||

__Table 3__: The light intensity (LUX) measured using lux meter during photosynthesis of Elodea that affects the temperature (°C ) inside the closed system that was measured to find out its relation to the rate of photosynthesis. As we can see from the table both the LUX (light intensity) is highest during noon but the temperature was highest in the morning, which means not all of the light intensity was absorbed at noon because the temperature was not really high even though the LUX was. The temperature of the closed system affects the rate of photosynthesis that came from the light intensity absorbed. Therefore, we can see that the rate of photosynthesis was highest in the morning but lowest in the afternoon because the temperature was not really high and so was the LUX. __ Processed Data __ __ Table 4 __ : The change of pH of water during photosynthesis of Elodea in a closed system (pH) from the raw data by using a pH sensor seen from the data logger graph with it being calculated to averaged and its standard deviation. It can be seen that the highest average change of water is observed during morning and afternoon which is 0.7. The lowest average change of pH is during noon which is 0.4. Change of pH indicates the uptake of Carbon Dioxide hence when change of PH is higher, the uptake of carbon dioxide will also be higher which results to higher rate of photosynthesis, vice versa. Hence it can be supported that there is higher rate of carbon dioxide uptake during morning and afternoon. __ Table 5 __ : The change in concentration of Oxygen Gas (mg/L) dissolved in water during photosynthesis of Elodea in a closed systemusing a dissolve oxygen probe which data is observed by the data logger graph and is averaged with the standard deviation. It can be seen that the highest change of dissolved oxygen concentration is observed during afternoon, which is 0.6. The lowest change of dissolved oxygen is during noon, which is 0.2. Change of dissolved oxygen concentration indicates the oxygen gas production of Elodea photosynthesis. The higher the change of dissolved oxygen concentration, the higher the rate of photosynthesis, vice versa. __Table 6__: The change in light intensity from the sun during photosynthesis of Elodea in a closed system (LUX) using a lux meter from a digit result. This data shows that the lowest change in light intensity is at noon while in the morning the LUX is the smallest. This means that the sun gave off bigger light in the afternoon and at noon the light intensity is really varied and not constant. This data shows the climate of the day whether it is cloudy or not and how it affects the rate of photosynthesis from the other data that we have. __Table 7__: The change in temperature of water (°C) during photosynthesis of Elodea in a closed system by measuring it using a thermometer from initial and after temperature. From the graph we can indicate that at in the afternoon the change of temperature is the highest which means that the temperature are not constant and means that the artificial pond didn’t absorb all the light intensity. As in noon it is minus, which is the lowest temperature change during the experiment. It means the change was really small or not at all, the change was higher in the other trials and that the light intensity was absorbed the most in this time of the day.
 * Time of Day || Hours  |||| Light intensity andchange of temperature measured during photosynthesis of Elodea in a closed system.  ||
 * ^  ||^   || LUX (__+__0.05 LUX)  || Temperature (±0.5°C)  ||
 * Morning || 8:30  || 21700  || 26  ||
 * ^  || 9:00  || 56300  || 31  ||
 * ^  || 9:30  || 53600  || 26.5  ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">10:00  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">64200  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">32.5  ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">10:30  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">37500  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">26  ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">11:00  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">41300  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">30  ||
 * <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">Noon || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">11:30  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">75000  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">26.5  ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">12:00  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">71200  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">32  ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">12:30  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">88200  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">25.5  ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">1:00  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">90200  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">33  ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">1:30  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">16540  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">25  ||
 * <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">Afternoon || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">2:00  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">19300  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">27  ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">2:30  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">74400  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">27.3  ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">3:00  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">43100  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">28  ||
 * Time of Day ||  Hours  ||||||  Change of pH of water during photosynthesis of Elodea in a closed system (pH)(__+__1.5x10-4pH)  ||
 * ^  ||^   ||   ||  Averaged  || Standard Deviation ||
 * Morning ||  8.30-9.00  ||  0.6  ||  0.7  ||  0.3  ||
 * ^  ||  10.00-10.30  ||  1.1  ||^   ||^   ||
 * ^  ||  10.30-11.00  ||  0.3  ||^   ||^   ||
 * Noon ||  11.30-12.00  ||  0.4  ||  0.4  ||  0.0  ||
 * ^  ||  12.30-1.00  ||  0.3  ||^   ||^   ||
 * ^  ||  1.00-1.30  ||  0.4  ||^   ||^   ||
 * Afternoon ||  1.30-2.00  ||  1.1  ||  0.7  ||  0.3  ||
 * ^  ||  2.00-2.30  ||  0.5  ||^   ||^   ||
 * ^  ||  2.30-3.00  ||  0.4  ||^   ||^   ||
 * Time of Day ||  Hours  ||||||  Change in concentration of Oxygen Gas dissolved in water during photosynthesis of Elodea in a closed system (mg/L)(__+__1.5x10-4 mg/L)  ||
 * ^  ||^   ||   ||  Averaged  || Standard Deviation ||
 * Morning ||  8.30-9.00  ||  0.6  ||  0.4  ||  0.2  ||
 * ^  ||  10.00-10.30  ||  0.2  ||^   ||^   ||
 * ^  ||  10.30-11.00  ||  0.3  ||^   ||^   ||
 * Noon ||  11.30-12.00  ||  0.2  ||  0.2  ||  0.0  ||
 * ^  ||  12.30-1.00  ||  0.2  ||^   ||^   ||
 * ^  ||  1.00-1.30  ||  0.3  ||^   ||^   ||
 * Afternoon ||  1.30-2.00  ||  1.2  ||  0.6  ||  0.4  ||
 * ^  ||  2.00-2.30  ||  0.2  ||^   ||^   ||
 * ^  ||  2.30-3.00  ||  0.5  ||^   ||^   ||
 * <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">Time of Day || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">Hours  |||||| <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">Change in light intensity from the sun during photosynthesis of Elodea in a closed system (LUX) (__+__0.15 LUX)  ||
 * ^  ||^   ||   || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">Averaged  || <span style="font-family: 'Verdana','sans-serif'; font-size: 13px;">Standard Deviation ||
 * <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">Morning || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">8.30-9.00  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">34,600.0  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">3900.0  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">25025.7  ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">10.00-10.30  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">-26,700.0  ||^   ||^   ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">10.30-11.00  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">3,800.0  ||^   ||^   ||
 * <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">Noon || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">11.30-12.00  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">-3,800.0  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">-25153.3  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">34381.0  ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">12.30-1.00  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">2,000.0  ||^   ||^   ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">1.00-1.30  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">-73,660.0  ||^   ||^   ||
 * <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">Afternoon || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">1.30-2.00  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">2,760.0  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">8853.3  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">35534.8  ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">2.00-2.30  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">55,100.0  ||^   ||^   ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">2.30-3.00  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">-31,300.0  ||^   ||^   ||
 * <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">Time of Day || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">Hours  |||||| <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">Change in temperature of water during photosynthesis of Elodea in a closed system (°C) (1.5)  ||
 * ^  ||^   ||   || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">Averaged  || <span style="font-family: 'Verdana','sans-serif'; font-size: 13px;">Standard Deviation ||
 * <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">Morning || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">8.30-9.00  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">5  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">0.8  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">5.2  ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">10.00-10.30  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">-6.5  ||^   ||^   ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">10.30-11.00  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">4  ||^   ||^   ||
 * <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">Noon || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">11.30-12.00  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">5.5  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">-3  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">6  ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">12.30-1.00  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">-6.5  ||^   ||^   ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">1.00-1.30  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">-8  ||^   ||^   ||
 * <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">Afternoon || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">1.30-2.00  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">2  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">0.1  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">0.4  ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">2.00-2.30  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">-1  ||^   ||^   ||
 * ^  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">2.30-3.00  || <span style="display: block; font-family: Verdana,sans-serif; font-size: 13px; text-align: center;">-0.7  ||^   ||^   ||

__Overall Graph:__

__Conclusion:__ Biology Conclusion: Our hypothesis is wrong in the biology part of the experiment, because what we said was the oxygen rate produced would be at its highest ability at noon during the photosynthesis inside the artificial pond. The result that we had achieved is that the light intensity from the sun at its highest peak is reached during afternoon, and the growth is constant. Our hypothesis is wrong. The light intensity proves to be a great asset in the production of oxygen during photosynthesis, especially at the afternoon because the light intensity, CO2 uptake which is measured by the pH sensor, temperature, oxygen gas production which is measured by the D.O connected with the data logger, proves to be at its highest rate during the morning, according to our first experiment, first thing in the morning. This can be seen from the table as in the morning the concentration of oxygen gas is averaged to be 0.6 mg/L, which is the highest than the other time of the day. While it is lowest at noon as the climate was cloudy this can be seen from the table, the averaged concentration of dissolve ware ris 0.2 mg/L. If those external factors measured are at it’s highest amount, the result would be assured to every discipline being measured to be of best quality. However, there are things that we need to improve at the next experiment. For example, our research wasn’t very efficient, because we only researched at a single source and concluded that the source was correct, and therefore making it unreliable, because we haven’t considered the possibilities of upper quality research from other websites. Also, the experiment we did proved to be very long, we need to explore for more experiments that can also be graded the same as our current experiment. Even if the umbrella topic is time, we cant risk the loss of too much time, because the wasted time can be used for other things that is also important, which we will be putting more research in the next biology experiment we are doing. Our chemistry hypothesis was wrong since the highest pH can be found in the morning that resulted that the rate of reaction is the fastest in this time of the day. As explained before it is because Carbon dioxide gas is one of the reactants for photosynthesis reaction. As there is photosynthesis the pH will change because we had put sodium bicarbonate to increase the CO2 and that resulted pH to decrease that can be seen clearer in the morning. However, the pH is lowest at noon because the light intensity absorb was low and there would be higher CO2 concentration (low CO2 uptake). The changes of pH is caused because if carbon dioxide dissolve (taken by the photosynthesis process) it will form carbonic acid that would lower down the pH of the water. Which means when it is used up in a photosynthesis reaction then the water pH would rise and the CO2 uptake would also rise. This happens the most in the morning even though it goes the same in the afternoon, averaged pH is the same (0.7 pH) but as the light intensity is absorbed higher in the morning than the afternoon which can be seen by the temperature (0.8 °C). As during noon there will be less sunlight, which means less light intensity and the rate at which carbon dioxide will be used is increased. The rate of photosynthesis will increase. This will result to a fast change of pH in the morning not at noon as our hypothesis stated. The pH of water will go down then constant as the amount of CO2 in each trial are constant (it cannot go further as to change the pH). This can be seen from the data, as in at noon the pH is only 0.4 which is the lowest average than all. The changes of data in noon for all the dependent variable is also the lowest which shows a minus result As in the hypothesis has explained before, it happened because of a reverse reaction, when the light intensity decrease the equilibrium position would shift to the left to increase the light (product) that also results in an increase of CO2 and water, while the O2 will decreased (as biology has explained) according to Le Chatelier’s Principle. This made the CO2 uptake to decrease as there is a bigger CO2 concentration in the water. Even though the light intensity is bigger in the afternoon, the temperature is highest in the morning, which means not all light was absorb which made us came to a conclusion that the CO2 uptake is biggest in the morning. Physics conclusion: Our hypothesis we stated that with the higher amount of intensity on the lux meter is, the higher the temperature, which shows that the flask has direct sunlight, which helps the plant with photosynthesis. Judging from our data, there has been minor problems recording the lux meter, but as shown by the change of temperature, we could assume that the flask has direct contact with sunlight. Which prove that with the increase of light intensity, the more there is to the temperature. What we should improve in the future is we should have an interval of at least 5- 10 minutes when we want to measure the lux, since a more often measurement can make the data more precise. From the perspective of a farmer, we can conclude that they shouldn’t not put your plants under a shadow but leave it under direct sunlight. This way there will be better photosynthesis on the plant itself. We can also conclude that in the afternoon even though there is more sunlight (light intensity) not all plants can absorb it, the absorbance of light intensity is better in the morning. Hence to grow a plant it is better in the morning since it can have a higher rate of photosynthesis. If they want to plant trees plant it during the day, as it can grow better. For the Binusians, we can see that children shouldn’t play in the morning but in the afternoon since in the morning there is a higher light intensity that can cause them sunburn in the garden. While in the afternoon there is more O2 which can make them have a sufficient energy and respiration with also sufficient vitamin D3 to absorb calcium as there is enough sunlight for them. __Evaluation__

There are a few strengths when doing the experiments. The first strength is the usage of data logger for measuring the oxygen dissolved in water and pH of water during photosynthesis. The data logger is capable of measuring the two variables continuously by seconds and draws it into graphs. This is an advantage because we will be able to see the data at anytime of the experiment using the graph. We will also be able to see patterns made such as if the pH increase or decrease when the sun is shining on the flask. It also has very minimal uncertainty, which is beneficial so there is less chance of errors Another strength is calibration of the ph and dissolved oxygen sensor is done before each trial so the sensors will return back to its original state. Therefore results from the previous trial will not affect the following trial. The third strength is the amount of trial we did for the experiments. We did three trials per time of day (morning, noon, afternoon) and after that determine the average. By performing more than one trials, the result we get will be more precise and will have less chance of anomaly. The fourth strength is we tried to keep the controlled variables under our control such as not moving the flask during the whole experiment. This is essential because moving the flask means changing the amount of sunlight reacting on the flask hence disturbing the photosynthesis reaction. Another controlled variable is making sure to use the same type of plant, which is elodea in every trial. By making sure to keep the controlled variable constant, we can make sure that the time of day is the only factor that is affecting photosynthesis reaction. The last strength is the usage of Plasticine to seal the opening of the flask. Plasticine is oil based therefore it will never dry and continuously stick to the opening of the flask. Using Plasticine to seal the flask is a benefit because it prevents oxygen gas from the environment to go inside the flask and contaminate the sensor hence affecting the data. It also keeps the carbon dioxide gas from the decomposition of sodium bicarbonate to stay inside the flask in order to initiate photosynthesis reaction in a closed environment. However, we also have some weaknesses to our method that needs to be improved. The first weakness is the fact that during the experiment, the plant was not heavy enough to stay in the bottom of the flask. Due to that, it keeps floating and touching the ph and dissolved oxygen sensor. This can create an inaccuracy to the data as the ph or the concentration of oxygen gas detected might not be the actual one since the plant is blocking the sensor. We can improve this by attaching a type of weight such as a small rock or pebble that can weigh down the plant so it can firmly stay at the bottom of the flask. The next weakness is our understanding towards data logger. It was our first time using data logger so we had limited understand towards it that results to the failure of one trial. We can improve this weakness by spending extra time to learn to use data logger so we will be prepared and have wider knowledge on it when doing the experiment next time. Another weakness is the fact that the day was cloudy at around 12 o’clock at noon. This is a weakness because it can create an anomaly to the data. The data about light intensity will be affected hence the photosynthesis rate will also be affected. We can improve this by testing the photosynthesis reaction during noon on the next day so we can observe the actual photosynthesis rate during noon. The next weakness is the fact that we only have one data logger and one of each pH and dissolved oxygen sensor therefore we weren’t able to perform several trials at once and have to wait for one trial to finish. To improve this, we might have to do further research about measuring carbon dioxide and oxygen using other methods that does not require data logger such as syringe method. Therefore we can investigate the photosynthesis rate for a specific hour instead of time of day, which is a broader concept.

Another weakness was always the change of light intensity for every second, therefore the sun may not be shining on the flask every second. As shown in the data we can see there some irregularities in the lux data, which is lower than the start point where the temperature is around 26 degree. Sometimes when we measure the light intensity, there is a sudden change of light due to a moving cloud which again affects the data. This can be improved by probably using mirrors to reflect the sunlight to the flask, therefore the flask will absorb all the light from the sun.

The last weakness is due to limited time; we can only investigate photosynthesis at a 30 minutes time range. This is a weakness because we cannot observe the full reaction of photosynthesis such as the full carbon dioxide uptake or the amount of oxygen gas production that is dissolved in water after the completion of reaction. We can improve this weakness by extending the time range to one hour so we can investigate photosynthesis more in depth. In order to improve the experiment, external things must be included. Things like the time of the day and the amount of time we were given. There are experiments that take way faster however our experiment requires time for its strongest element is the difference of the results based on different times of the day. Therefore, it would be better to perhaps have a three-day experiment in order to reach the full potential of the results.

__Evidence:__