Solving an Ice Cream Conundrum with Temperature Conversion and Salt

  • Thread starter Thread starter robbie
  • Start date Start date
  • Tags Tags
    Word problem
AI Thread Summary
The discussion centers on solving a complex word problem involving temperature conversion and the principles of making ice cream. It explains the process of converting 3 kg of ice at -30 degrees C to steam at 120 degrees C using heat energy calculations. The key formula used is Q = m * c * ΔT, which helps determine the heat energy required for each phase change. To create soft ice cream from ingredients at 5 degrees C to -5 degrees C, the discussion emphasizes the importance of using ice at 0 degrees C mixed with salt to lower the freezing point and achieve the desired temperature. The conversation highlights the scientific principles behind temperature changes and the role of salt in the ice cream-making process.
robbie
Need help on this word problem please. I don't even know where to start with this one.

If you convert 3 kg of ice at -30 degrees C into 3 kg of steam at 120 degrees C. Using this as a model can you explain how we make ice-cream with ingredients of 5 degrees C into soft ice-cream at temperature of -5 degrees C using ice at 0 degrees C as the coolant? (remember the salt)

THANKS.
 
Physics news on Phys.org
It might help if you posted the problem as given.
Surely it didn't start "If you convert 3 kg of ice at -30 degrees C into 3 kg of steam at 120 degrees C." That's not a sentence!

If ... then what??
 


Sure, I'd be happy to help with this ice cream conundrum! First, let's break down the problem into smaller steps. The first step is to convert the units of measurement to make the problem easier to understand. So, we need to convert 3 kg of ice at -30 degrees C into 3 kg of steam at 120 degrees C.

To do this, we can use the formula: Q = m * c * ΔT
where Q is the heat energy, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature.

Since we are converting from ice to steam, we can use the specific heat capacity for water, which is 4.18 J/g°C. So, the first step would be to calculate the heat energy required to convert 3 kg of ice to water at 0 degrees C.

Q = (3 kg) * (4.18 J/g°C) * (30°C) = 376.2 kJ

Next, we need to calculate the heat energy required to convert 3 kg of water at 100 degrees C to steam at 120 degrees C.

Q = (3 kg) * (4.18 J/g°C) * (20°C) = 250.8 kJ

Now, to make ice cream using the same principles, we need to take the ingredients at 5 degrees C and convert them to -5 degrees C. To do this, we can use the same formula, but this time the ΔT will be negative since we are going from a higher temperature to a lower temperature.

Q = (m) * (4.18 J/g°C) * (-10°C)

To make the ice cream, we need to remove heat energy from the ingredients, which is why the ΔT is negative. Now, we need to figure out how much heat energy we need to remove to get the ingredients to -5 degrees C.

Q = (m) * (4.18 J/g°C) * (-10°C) = 50 J

Now, the last step is to use ice at 0 degrees C as the coolant. To make the ice cream, we need to use a mixture of ice and salt. The salt lowers the freezing point of water, making it colder than 0 degrees C. This will help us achieve the desired temperature of -5 degrees C for our ice cream.

 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Back
Top