Question

I had to heat 6 eggs. 3 in boiling water, 3 in the oven. I had to take them out at 5, 10, & 15 minutes. I then placed them each in cold water. I had to observe what happened to each egg and now I have to answer these questions. I don't understand what temperature gradient means and what type of answer he is looking for.

1. Heat transfer is both external, from the water or air to the egg, and internal, from the outside of the egg towards the yolk. Which method is best at transferring heat from the fluid to the eggshell? boiling or baking at 450 degrees? Compare the temperature gradients from boiling and baking in the two methods. Which of the methods produces the most pronounced gradient? Which of the methods is likely to produce the most consistent hard cooked egg?

Answer 1

You have not provided the data recorded in your experiment so I can only explain you the theory behind it.

By temperature gradient we mean difference in temperatures developed between the outer surface and inner core of the egg with respect to time.

When you bake an egg, you are basically using hot air as a method of providing heat, while in boiling you make use of hot water.

Boiling with hot water is a quicker method, which means it would give a steeper gradient, which means it would quickly heat up the inner core of the egg as compared to hot air, because air would transfer heat slowly since it is a bad conductor than water.

So, the pronounced (steeper) gradient is produced by boiling water. But more hard cooked egg will be produced by oven, because it will take more time to heat the egg so heat transfer will take slowly and the egg will have much time to get hardened.

Hope this helps !