# Physics IA - Thermal Physics

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So we got a lab to do ourselves over the winter break, and the instructions we got (as usual) were super ambiguous. But considering we haven't touched upon thermal physics that much, I was hoping I could get some help from you guys (: This is the assignment:

• Bob just poured himself a cup of steaming hot coffee. Bob likes his coffee hot and likes cream in his coffee. He goes to his fridge to get the cold cream. Just before pouring the cream in his coffee ... ding dong ! someone is at the door. What should Bob do? Pour the cream in now, or wait until he gets back from the door? Bob does like his coffee hot ...
There are many aspects of this situation that can be analyzed. The solution to this problem depends on many things. Decide on one and analyze it. Do a full IB write-up of the lab. Be sure to include at least one graph

What I have so far is basically just carrying out the experiment by pretty much carrying out the situation where i have two cups of coffee, put the cream in one right away, and measure the temperature over a 10 minute period? I think that would be a really bad graph to have because it's only a time/temperature graph so I don't know if it would show the effect of adding the cream? I also was thinking about making the temperature of the cream while adding it the independent variable, would that makes sense?

thanks for any help in advance =)

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Well since my biology teacher was told to make his lab directions less straightforward, I think your teacher is playing it safe

I'm not sure I understand what you mean by 'I also was thinking about making the temperature of the cream while adding it the independent variable'

How willing are you to look at this lab from another angle?

One possible thing [which is what you are already talking about] would be having several cups of coffee. Bob normally put X amount of cream. How much should he put to get it to Y Kelvins/degCelsius? I don't know if you have the power to change the lab like that, but if that was your premise, then I think you could do a nice experiment with it.

Also your teacher said there are lots of aspects you can look at. Have you heard of bomb calorimetry versus coffee cup calorimetry? [it's not nearly as exciting as it sounds, as much as I love thermochemistry]. Analyze the equation you're looking at Q=mC(delta)T. C is the specific heat...

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Well since my biology teacher was told to make his lab directions less straightforward, I think your teacher is playing it safe

I'm not sure I understand what you mean by 'I also was thinking about making the temperature of the cream while adding it the independent variable'

How willing are you to look at this lab from another angle?

One possible thing [which is what you are already talking about] would be having several cups of coffee. Bob normally put X amount of cream. How much should he put to get it to Y Kelvins/degCelsius? I don't know if you have the power to change the lab like that, but if that was your premise, then I think you could do a nice experiment with it.

Also your teacher said there are lots of aspects you can look at. Have you heard of bomb calorimetry versus coffee cup calorimetry? [it's not nearly as exciting as it sounds, as much as I love thermochemistry]. Analyze the equation you're looking at Q=mC(delta)T. C is the specific heat...

well you can look at not only the thermal energy Q but the latent heat Q. think about that and then maybe you just might understand this really ambiguous case

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I'm doing a similar IA except mine is cold milk instead of cream

I decided to use hot water and cold water instead of making hundresds of cups of coffee and wasting milk.

I'm doing at least 5 trials each time, and my teacher told me to look at it from a different angle so I thought of changing the volume of cold milk:

but I don't know which I'm investigating:

how the volume of cold milk affects final temp

or WHEN to pour in the cold milk

honestly.... I'm stuck there as well.

Also for my volume and things, my teacher told me to use SHC (specific heat capacity)

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So you've got three variables floating around. Final temperature, volume of cold milk [or cold water], and time. Hold one of these constant, and then the remaining two will be the independent and dependent variables.

If you say you like your drink at X degrees Celsius, then you can look at how the volume of cold water affects the time it takes to get the drink to the temperature needed.

If you only have X mL of cold water, you can look at what temperature your drink gets at different times or how much time it takes to get your drink to certain temperatures.

You can do other variations as well.

Are you confused about the SHC? As far as I know, it's the same thing as specific heat, and you can use Q [heat] = mass * specific heat * change in temperature

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