Bio Lab

Siddharth Tirumala Mrs. Kiriazis IB1 Biology 22 August 2013 Diffusion Lab Write-Up Research Question: How does the temperature of the water affect the diffusion of food coloring? Hypothesis: Food coloring will dissolve faster as the temperature of the water increases. Variables: Name of Variable| What is it? | How is it measured? | Units| Range of the data| Independent | Temp. of Water | Thermometer | oC (Celsius)| | Dependent | Rate of diffusion of food coloring | Stopwatch | Min (Minutes)| |

Controlled variables in the experiment include the type of beaker used (150mL max), the amount of water used for each trial (100mL), and the amount of drops of food coloring used for each trial (2 drops). These things were necessary to keep the same in the experiment because if they were changed, it would skew the data and make it inaccurate. Procedure: 1. Get all materials (150mL beaker, food coloring, thermometer, 100mL of water, hot plate, stopwatch) 2. Fill beaker with 100ml of water. nd measure the temperature of it (21°C right from the sink). 3. Drop two drops of food coloring, start the stopwatch, and measure how long it takes for the food coloring to completely diffuse. 4. Once finished, get rid of the water and do another trial. 5. Once done with the second trial, fill beaker with 100mL again. 6. Heat water to 30 degrees Celsius and drop two drops of food coloring, start the stopwatch, and measure how long diffusion takes. 7. Do another trial. 8. Repeat steps 2-4 for 40 and 50 degrees Celsius. 9.

Once finished collecting data, clean up messes and put away materials. Data: Raw Data: Temperature (°C)| Diffusion of Food Coloring Trial 1 (s)| Diffusion of Food Coloring Trial 2 (s)| 21°C| 250 s| 243 s| 30°C| 147 s| 143 s| 40°C| 56 s| 63 s| 50°C| 45 s| 40 s| Calculated Data: Temperature (°C)| Diffusion of Food Coloring Trial Average (s)| 21°C| 246. 5 s| 30°C| 145 s| 40°C| 59. 5 s| 50°C| 42. 5 s| Graph: Conclusion: In conclusion, as the temperature of the water increased, the rate of diffusion of the food coloring decreased.

For example, at 21°C, the average time it took for the food coloring to diffuse was 246. 5 seconds. At 50°C, the average time it took for the food coloring to diffuse in the water was 42. 5 seconds. The bar graph above visually shows the trend. The reasoning for this trend can be explained with the fact that as the temperature increases, the particles move faster. The particles in the warmer water move at a faster rate, which in turn, spreads the food coloring faster than the particles in the colder water which move slower.

However, there probably was some error in the experiment. Some possible errors in the experiment could include not measuring 100mL exactly in the beaker. Another possible error could have been that the drops of food coloring could have been different sizes. Another error could’ve been that there could have been some hesitation when pressing start/stop on the stopwatch. the start/stop buttons could have pressed at the wrong times. All of these things could have contributed to some inaccuracy in the data.

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