At a restaurant, your glass of water contains 25% ice while your friend’s glass of water contains 75% ice. What can you say about their temperatures? Explain your answer
In both cases the temperatures will be close to 0°C.
Whenever you have water and ice in thermal equilibrium, the temperature will be 0°C. When you put a big piece of ice in water at room temperature, then the ice will at first melt fast, but this costs a lot of heat, and the water cools down rapidly. The water-ice system quicly reaches a steady state situation very near to thermal equilibrium.
The water will be very close to 0°C, but just a bit warmer than that, especially near the edge of the glass it will be a bit warmer. Near the ice it will be colder, only slightly above 0°C. The ice itself will be 0°C at the surface, the interior of the ice will be slightly below 0°C.
Then you know that heat flows from high temperature to low temperatures. So, these small temperature differences cause heat flow from the surrounding air into the glass of water and rom there into the ice which slowly causes the ice to melt.
To compare the temperatures of the two glasses of water with different ice percentages, we need to understand the relationship between ice and temperature. When ice melts, it absorbs heat from its surroundings. This process is called heat absorption or heat transfer. Since ice has a lower temperature than the surrounding environment, it cools down the water when it melts.
In the given scenario, if the glass of water contains 25% ice, it means that the remaining 75% of the glass is filled with liquid water. Therefore, we can assume that the temperature of the glass of water with 25% ice is closer to that of liquid water rather than ice. Hence, we can infer that the glass of water with 25% ice has a higher temperature compared to the glass with 75% ice.
Conversely, in the case of the glass of water with 75% ice, it implies that only 25% of the glass is filled with liquid water, and the remaining 75% is occupied by ice. As a result, we can conclude that the temperature of this glass of water is closer to that of the ice rather than liquid water. Therefore, the glass of water with 75% ice has a lower temperature compared to the glass with 25% ice.
In summary, the glass of water with 25% ice has a higher temperature, while the glass of water with 75% ice has a lower temperature.