### I have 2 glass beakers, each filled with water at 99.0C in a room that is 24.8C…………………..?

I’m going to take the two glass beakers filled with hot water out of the oven and start a stop watch. I’m going to immediately set them both on a wood surface. When the stop watch hits 1:00 minute, I’m going to add 40ml of water at 24.8C to one of the beakers. When the stopwatch hits 9:00 minutes, I’m going to add 40ml of water at 24.8C to the second beaker. At 10:00 minutes, I’m going to record the temperatures of each.

Will the temperatures be the same or will one be hotter? Why?

1. Orchid
on November 30th, -0001

Your heat flux out of the beakers will be dependent on the temperature gradient between the water and the air. The higher the gradient (that is, the larger delta T is) the faster you will lose heat to the air. So by cooling beaker A right away you will decrease the rate at which you’re losing heat to the surroundings. Beaker B will be losing energy faster than A due to its higher gradient, and then when you pour in the ambient water you will cool it down either further. B will have lost more energy to the atmosphere over the 9 minutes than A, and hence adding the same amount of ambient water will result in less energy in B than A. B will be cooler, as you’ve shown.

### I have 2 glass beakers, each filled with water at 99.0C in a room that is 24.8C……………………….

I’m going to take the two glass beakers filled with hot water out of the oven and start a stop watch. I’m going to immediately set them both on a wood surface. When the stop watch hits 1:00 minute, I’m going to add 40ml of water at 24.8C to one of the beakers. When the stopwatch hits 9:00 minutes, I’m going to add 40ml of water at 24.8C to the second beaker. At 10:00 minutes, I’m going to record the temperatures of each.

Will the temperatures be the same or will one be hotter? Why?

1. Cocktail
on November 30th, -0001

Naman