Group+19

**Introduction:** This experiment will investigate the changes to the properties of potato when in undergoes osmosis in white vinegar after a period of time. This experiment will find out how acidic substances affect food. This is important because the acidity of the food we eat may affect our stomach. If the food we eat is too acidic then we may get stomach ache. It affects the Binus community because stomach aches may cause students to be absent from school and miss important lessons. This seems to be the most common illness students experience in Binus. **AIM:** To investigate the result of the properties of a potato when the potato is soaked in white vinegar within a 10 minute interval for 50 minutes.
 * **__ Biology: __** To investigate the change in the mass of the potato as a result of osmosis.
 * **__ Chemistry: __** To investigate the change in the pH of the potato as a result of soaking it in an acidic solution (vinegar).
 * **__ Physics: __** To investigate the density of the potato overtime in white vinegar.

**HYPOTHESIS:**
 * The mass of the potato will decrease due to osmosis happening as the water molecules of the potato move from the potato to the vinegar.
 * The pH will decrease from the initial pH as the vinegar makes the potato absorb its acidity.
 * The density of the potato decreases overtime since osmosis causes water to go into the vinegar.

**VARIABLES:**


 * Independent **
 * ** Time (10mins, 20mins, 30mins, 40mins and 50mins): ** The potato will be soaked within a 10 minute interval for 50 minutes.


 * Dependent **
 * The change in mass (g)
 * The change in pH
 * The change in density


 * Controlled **
 * ** Size of potatoes: ** All the pieces of potatoes will be cut into identical sizes of 2x2x1. All potatoes will be equally submerged into the 60ml solution of vinegar to ensure fairness in each trial.
 * ** Temperature: ** All trials will be conducted in room temperature of the same room in order to prevent the temperature of the room from affecting the experiment.
 * ** Volume of vinegar: ** The volume of the vinegar in the measuring cylinder will always be 60ml so the experiment is fair.

**APPARATUS:**
 * Measuring cylinder
 * pH paper
 * Digital Balance
 * White Vinegar of 25%
 * Cloth
 * Potatoes
 * Pitcher
 * Stop Watch
 * Thong
 * Knife
 * Cutting Board

**PROCEDURE:**
 * 1) The materials were collected and prepared
 * 2) 5 potato blocks were cut with the length of 2cm and width of 1 cm
 * 3) The vinegar was poured into the measuring cylinder. The initial volume of the vinegar must be 60 ml.
 * 4) The first potato was measured on the electric balance and recorded
 * 5) Then the potato cube was soaked into the vinegar and the stopwatch was started. The increase in the volume of the vinegar when the potato was inserted is recorded.
 * 6) After 10 minutes, the potato was weighed on the electric balance and recorded. Then a slit was made in the potato and a pH paper was rubbed in the slit to check the pH.
 * 7) The potato was inserted back in and step 6 was repeated another 4 times per 10 minutes.

**RAW DATA:**
 * **__ Biology & Physics: __**

The mass of the potatoes every 10 minutes

(±0.01 s) |||||||||||||| Mass (grams)(±0.01 grams)  ||
 * Time (seconds)
 * ^  || Trial 1 || Trial 2 || Trial 3 || Trial 4 || Trial 5 || Trial 6 || Trial 7 ||
 * 0 || 4.64 || 4.40 || 4.88 || 4.61 || 4.86 || 4.32 || 4.30 ||
 * 600 || 4.66 || 4.42 || 4.74 || 4.47 || 4.69 || 4.26 || 4.24 ||
 * 1200 || 4.64 || 4.38 || 4.74 || 4.48 || 4.75 || 4.11 || 4.14 ||
 * 1800 || 4.59 || 4.33 || 4.77 || 4.52 || 4.70 || 4.02 || 4.07 ||
 * 2400 || 4.60 || 4.31 || 4.76 || 4.44 || 4.67 || 3.92 || 4.03 ||
 * 3000 || 4.57 || 4.41 || 4.67 || 4.41 || 4.58 || 3.85 || 3.95 ||
 * **__ Chemistry: __**

The pH of the potatoes every 10 minutes
 * ** TIME (minutes) ** ||||||||||||||  ** pH **  ||
 * ^  ||  ** Trial 1 **  ||  ** Trial 2 **  ||  ** Trial 3 **  ||  ** Trial 4 **  ||  ** Trial 5 **  ||  ** Trial 6 **  ||  ** Trial 7 **  ||
 * ** 0 ** || 7 || 7 || 7 || 7 || 7 || 7 || 7 ||
 * ** 10 ** || 3 || 4 || 4 || 4 || 4 || 4 || 4 ||
 * ** 20 ** || 3 || 3 || 3 || 3 || 3 || 3 || 3 ||
 * ** 30 ** || 3 || 3 || 3 || 3 || 3 || 3 || 3 ||
 * ** 40 ** || 3 || 2 || 3 || 3 || 3 || 3 || 3 ||
 * ** 50 ** || 3 || 2 || 3 || 3 || 3 || 3 || 3 ||

**PROCESSED DATA:**
 * **__ Biology: __**

The Average Mass of The Potatoes **(second)** **(****±0.01 s)** ||||||||||||  **Mass (grams)(****±0.01 grams)**  ||||  **Average mass** **(grams)** **(****±0.01 grams)** ||
 * **Time**
 * ^  ||||  Trial 5  ||||  Trial 6  ||||  Trial 7  ||||^   ||
 * 0 ||||  4.86  ||||  4.32  ||||  4.30  ||||  4.49  ||   ||
 * 600 ||||  4.69  ||||  4.26  ||||  4.24  ||||  4.40  ||   ||
 * 1200 ||||  4.75  ||||  4.11  ||||  4.14  ||||  4.33  ||   ||
 * 1800 ||||  4.70  ||||  4.02  ||||  4.07  ||||  4.26  ||   ||
 * 2400 ||||  4.67  ||||  3.92  ||||  4.03  ||||  4.21  ||   ||
 * 3000 ||||  4.58  ||||  3.85  ||||  3.95  ||||  4.13  ||   ||

The Graph of The Average Mass
 * **__ Chemistry: __**

The Average pH of the potatoes


 * ** TIME (minutes) ** ||||||  ** pH **  ||  ** Average pH **  ||
 * ^  ||  ** Trial 5 **  ||  ** Trial 6 **  ||  ** Trial 7 **  ||   ||
 * ** 0 ** || 7 || 7 || 7 ||  7  ||
 * ** 10 ** || 4 || 4 || 4 ||  4  ||
 * ** 20 ** || 3 || 3 || 3 ||  3  ||
 * ** 30 ** || 3 || 3 || 3 ||  3  ||
 * ** 40 ** || 3 || 3 || 3 ||  3  ||
 * ** 50 ** || 3 || 3 || 3 ||  3  ||

The graph of the Average pH
 * **__ Physics __**

Mass of potato over time

**CONCLUSION:** Our experiment was quite successful since we were able to complete all 7 trials in time without any problems. The weight of the potatoes had decreased when they were submerged into a solution of vinegar because the water molecules in it had diffused into the vinegar, which was what we had predicted. The hypothesis that our group had came up with for biology was correct since the vinegar contained a higher solute concentration and the potatoes contained a lower solute concentration, because of this we predicted that osmosis would occur. Osmosis is the movement of water molecules from an area of low solute concentration to an area of higher solute concentration that occurs to equalize the concentrations on each side and, since the vinegar had a higher solute concentration compared to the potatoes, the water molecules in the potatoes had diffused into the vinegar. For physics the hypothesis was also correct because from the experiment we have achieved the fact that density decreases over time since osmosis causes water to go into the vinegar. And time is part of the process when the density of the potato is required to have more time in order for it to decrease. For chemistry, submerging a cube of potato in vinegar causes the potato to absorb the acetic acid. This is why the pH of the potato had fallen significantly. We also observed that it did not take a long time for the pH to fall.

**EVALUATION:** The group had handled the experiment very well and we worked collaboratively together by contributing both ideas and solutions to the experiment. One of the ways our group could have improved this experiment, would be to dry the potatoes more carefully. After 10 minutes we had to take a potato out of the solution of vinegar to measure its mass but before this we had to dry the potato so its mass would be accurate. However we can see in some of the data that in some places where the mass should have decreased it increased, therefore to improve this we should dry the potatoes properly so the mass of the potato doesn’t increase due to the vinegar. Another factor we could improve for future experiments would be to find a better way to take the potato out of the measuring cylinder since in some trials we exceeded our limit of 10 minutes. We can solve this by poking the potato with the sharp wire a few minutes before we need to take it out, in order to be able to remove the potato in time. Another limitation that we faced was that the data is does not represent the pH of the entire potato but rather only the surface of the potato. Since we made an incision on the surface and tested the pH using pH paper. Squeezing the juice out of the potato after 10 minutes and then testing the pH can improve this procedure. However, this would be very time consuming since we would need 5 cubes of potatoes for each trial and test it multiple times.