Investigating the Relationship Between the Rate of Decay of Milk and Temperature

The video explores the relationship between milk decay and temperature, presenting two experiments. The first involves monitoring pH changes in milk over time at different temperatures. The second uses lipase to model milk decay by observing pH changes in a milk and sodium carbonate mixture. Catherine conducts the experiment, maintaining a constant temperature using a water bath. Results are analyzed, showing that lipase activity increases with temperature up to an optimum of 40°C, after which it decreases.

What is the primary cause of milk decay?

• pH stabilization

• Bacterial activity

• Temperature increase

• Lactic acid production

How can the rate of milk decay be monitored?

• By checking the smell

• By measuring the temperature

• By observing color change

• By tracking pH changes over time

What role does sodium carbonate play in the alternative experiment?

• It neutralizes the lipase

• It lowers the temperature

• It raises the pH of the milk

• It acts as a catalyst

Why is it important to maintain a constant temperature during the experiment?

• To ensure the milk does not evaporate

• To accurately measure the rate of reaction

• To prevent bacterial growth

• To keep the lipase inactive

What is the purpose of using a pH meter in the experiment?

• To ensure the water bath is working

• To check the volume of milk

• To measure the temperature

• To monitor the acidity level

What was the time taken for the pH to drop below 7 at 30 degrees centigrade?

• 320 seconds

• 201 seconds

• 173 seconds

• 243 seconds

Why was there no result at 10 degrees centigrade?

• The temperature was too high

• The time taken was too long

• The experiment was not conducted

• The pH did not drop

What does the graph indicate about the relationship between temperature and lipase activity?

• Lipase activity is highest at the lowest temperature

• Lipase activity increases with temperature up to an optimum point

• Lipase activity is unaffected by temperature

• Lipase activity decreases with temperature

What is the optimum temperature for lipase activity according to the experiment?

• 30 degrees centigrade

• 20 degrees centigrade

• 40 degrees centigrade

• 50 degrees centigrade

What happens to lipase activity above the optimum temperature?

• It remains constant

• It stops completely

• It decreases

• It increases