Important brain needed aluminum rods expirement

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Discussion Overview

The discussion revolves around the effect of inserting aluminum rods into a beaker of water on the time it takes for the water to reach a temperature of 75 degrees Celsius when heated. Participants explore concepts related to heat capacity, energy transfer, and the interaction between aluminum and water in a thermal context.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant questions whether the insertion of aluminum rods affects the heating time of water, suggesting that increased mass may lead to longer heating times due to energy requirements.
  • Another participant highlights the difference in heat capacities between water and aluminum, noting that water requires more energy to raise its temperature compared to aluminum.
  • A participant asks if the presence of aluminum would consume energy that could otherwise be used to heat the water, indicating a potential delay in reaching the target temperature.
  • One contribution suggests that the aluminum rods would draw from the heat source, affecting the final temperatures of both substances.
  • Another participant proposes considering an idealized setup to simplify the analysis, questioning how the heating time would differ if the beaker were filled entirely with aluminum instead of water.
  • A later reply emphasizes the need for more details about the experimental setup, such as whether the rods are fully submerged or if they displace water, to provide a more accurate response.

Areas of Agreement / Disagreement

Participants express varying opinions on the impact of aluminum rods on the heating time of water, with no consensus reached. Some agree that heat capacity differences are relevant, while others emphasize the need for more specific details about the experimental conditions.

Contextual Notes

Participants note limitations in the discussion, such as missing assumptions about the experimental setup and the need for clarity on whether the volume of water displaced by the aluminum rods is accounted for.

14mflohr
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super important for science- What's the relationship between Al and H2O

Does the insertion of aluminum rods into a beaker of water affect the time it takes for the temperature of the water to reach 75 degrees Celsius when heated?

I believe it would because there is more mass but I'm not sure and I don't know why (as in the law of equation to verify this.)

Could someone please tell me whether it would or not and how to prove it?

Thank you so much! :)

I would guess that the more mass of aluminum you put in the longer it will take to reach 75 degrees because of the amount of energy needed of something like that.. maybe the equation QΔ= M(TΔ)Cp <-- maybe
PLEASE HELP
 
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What happens is that when you insert the aluminum rods both the water and the aluminum. And it is not just a matter of "mass". Water and aluminum have different "heat capacities", the energy necessary to raise the temperature 1 degree C.
As you can see here: http://www.iun.edu/~cpanhd/C101webnotes/matter-and-energy/specificheat.html
Water has a heat capacity of approximately 4.2 Joules per gram per degree and aluminum has a heat capacity of approximately .9 J per gram per degree.
 


Thanks:) also though if I put an aluminum rod into a beaker of water then heat the beaker will it take longer for the water to reach 75 celsius because they have different heat capacities. Will the aluminum use up energy that would otherwise be used to heat the water?
 
Important brain needed:) aluminum rods expirement

If I put an aluminum rod into a beaker of water then heat the beaker on a hot plate, will it take longer for the water to reach 75 celsius compared to when it is heated alone? Someone helped me by saying that they have different heat capacities. Will it take longer for the water to reach 75 degrees celsius if the aluminum rod is inside? Would the aluminum use up energy that would otherwise be used to heat the water? Please explain and give me an equation or law of sorts to explain to others:)
thanks!
 


What do you think? We cannot answer your question until you have tried to answer it yourself.
 


I believe it would because the aluminum and water will both draw from the heat source. Aluminum needs approximately 0.9 joules of energy to raise one degree and water needs 4.79 joules. Because of this the aluminum rod and water will have different final temperatures. The tests that I did suggest that the aluminum rods do use a fraction of the heat source. What I don't know how to do is to figure out what percentage of the energy the aluminum uses, or what equation to use. I thought that maybe surface area is a part of it considering the aluminum rods only touch a small section of the beaker that's being heated while the water is touching much more. I don't need anyone to do the equations for me if they don't want to or aren't allowed, I'm just asking for some help in which direction I should proceed.
 


anyoneeee? :P
 


You should probably ignore the configuration of the rod and beaker, and consider it simply an idealized setup. Also, assume the water and rod have enough time to reach equilibrium with each other (i.e. they are the same temp)

Think about how long it would take warm up a gallon of water. Then think of how long it would take to warm up a gallon of aluminum rod. Consider the specific heat of each.

If the beaker were completely full of the aluminum rod, would it heat up faster or slower than if it were full of water?
 


Did not realize this was a dupe post.
 
  • #10


14mflohr said:
If I put an aluminum rod into a beaker of water then heat the beaker on a hot plate, will it take longer for the water to reach 75 celsius compared to when it is heated alone? Someone helped me by saying that they have different heat capacities. Will it take longer for the water to reach 75 degrees celsius if the aluminum rod is inside? Would the aluminum use up energy that would otherwise be used to heat the water? Please explain and give me an equation or law of sorts to explain to others:)
thanks!

Welcome to the PF. Please do not multiple post your question. I have merged two of your three threads.
 
  • #11


14mflohr said:
anyoneeee? :P

You haven't given us enough information to answer the question. Are you simply inserting aluminum rods into the water? Do you remove exactly the same volume of water that the aluminum rods displace? Are the rods completely submerged or are their ends hanging out like a heat exchanger?

Details! DETAILS!
 

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