Carrot cake is a tasty, but it's not the simplest cake to bake. This trick from America's Test Kitchen doesn't cut down on the cooking time, but it does shrink the prep to only 15 minutes, uses your slow cooker, tastes delicious, and is healthier to boot. Here's how it works, and where to get the recipe.
    
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Leaving for a vacation is always a bit of a stressful time as you run around the house and get everything ready. Before you hit the road, it's worth running through Apartment Therapy's checklist of 10 things you need to check before you leave the house.
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Freshly made mozzarella cheese is a delight, but it gets ruined if stored in the fridge. If you have store-bought or previously refrigerated mozzarella, all hope is not lost, though. Serious Eats says you can rescue the cheese with a warm milk bath.
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We're approaching that time of year when shoppers go into a frenzy, lured by "doorbusters" and potential savings. If you'd like to get in on the savings but would rather avoid the craziness, you can do that now, simply by using the right credit card.
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Back in the day, web browsers didn't mean quite as much. Now they are an integral part of our lives. While we could just go with the system default back in the day, now passionate users support their browsers as fervently as their operating systems. We took the two most popular—Chrome and Firefox—and asked you to prove which one is better. Here's what you said.
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College is expensive and there's no getting around that unless you have a time machine and can lock in older, cheaper tuition rates. Alternatively, finance blog Dumb Little Man suggests using a 529 plan to prepay at today's rates for college in the future.
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Parallel parking can be a a challenge for even the most seasoned drivers. Thankfully, over at Quora, Yishan Wong offers this step-by-step breakdown of how to parallel park perfectly every single time—and he’s spot on.
Whenever I visit the airport or hunker down for a road trip, I tend to give myself a little more leeway when it comes to buying food. Actually, a lot more leeway. That means a burger there, a slice of pizza here, waffles and coffee galore. But a few things have cooled down my enthusiasm for "treating myself" with food when I travel—mainly overpriced meals and a general lack of healthy, satisfying options.
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If your dog doesn't do a great job of letting you know when he or she needs to go for a walk, or you live somewhere you may not hear or see your dog pacing at the door, wanting to outside, this DIY doggie doorbell is a weekend project both you and your pet will appreciate.
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In an effort to include more wireless data in its periodic reports on the state of broadband in America, the Federal Communications Commission has released an Android app that lets consumers test the speed and quality of their wireless provider (and of course shares that data with the FCC).
FCC Speed Test is currently available via the Google Play app store. Once installed, users can choose to run a test or just have the app occasionally run one in the background.
The app tests four different aspects related to wireless broadband — download speed, upload speed, latency, and packet loss. If a user chooses to run a test on her own, she can pick and choose which of these categories to include. The Commission says it prefers data from random background testing as manually initiated tests “can lead to biased results when performed only at specific times or places, and may provide a less accurate picture of overall broadband performance.”
By default, the tests will eat up a maximum of 100MB/month of data usage, but this number can be changed in the settings to whatever the user wants it to be.
Given the recent revelations about various federal agencies nosing into supposedly private data, there are obvious privacy concerns for some people about installing an app that provides information to the FCC.
According to the Commission, in addition to the speed and quality test results, the app records four other types of information:
1. Location — this includes the location and ID of the cell tower through which your phone connected for the test. It also includes the GPS location for your device.
2. Time of data collection — pretty self-explanatory, this involves recording the start and end times of the test.
3. Handset type and operating system version — what type of device you’re using and what OS you’re running.
4. Cellular performance and characteristics — including your service provider, the strength of the radio signal, and what type of connection (3G or 4G) service you have.
The FCC claims that the data gathered by the test is entirely anonymous and that any reports made public will only consist of aggregated, anonymous data. You can check out the entire privacy policy here.
Police investigators are trying to determine what happened to a critically injured infant who lived in a home they say had been converted for growing marijuana.
Redskins wide receiver Pierre Garcon had his head shaved Tuesday after losing a fundraising battle for childhood cancer.
The Supreme Court won't hear an appeal from three former Duke University lacrosse players who were among those falsely accused of raping a stripper
This Veterans Day, an animal rescue group has found a way to help a soldier who suffers from PTSD.
The Richmond Times-Dispatch reports that the number of dolphin deaths has fallen from 172 in August to 31 in October
This Veterans Day, an animal rescue group has found a way to help a soldier who suffers from PTSD.
I was absentmindedly stirring a cup of hot tea, when I got to thinking, "aren't I actually adding kinetic energy into this cup?" I know that stirring does help to cool down the tea, but what if I were to stir it faster? Would I be able to boil a cup of water by stirring?
Will Evans
No.
The basic idea makes sense. Temperature is just kinetic energy. When you stir tea, you're adding kinetic energy to it, and that energy goes somewhere. Since the tea doesn't do anything dramatic like rise into the air or emit light, the energy must be turning to heat.
The reason you don't notice the heat is that you're not adding very much of it. It takes a huge amount of energy to heat water; by volume, it has a greater heat capacity than any other common substance.[1]Hydrogen and helium have a higher heat capacity by mass, but they're diffuse gasses. The only other common substance with a higher heat capacity by mass is ammonia. All three of these lose to water when measured by volume.
If you want to heat water from room temperature to nearly boiling in two minutes, you'll need a lot of power:
\[1\text{ cup}\times\text{Water heat capacity}\times\tfrac{100^\circ\rm{C}-20^\circ\rm{C}}{2\text{ minutes}}=700\text{ watts}\]
(Note: Pushing almost-boiling water to boiling takes a large burst of extra energy on top of what's required to heat it to the boiling point—this is called the enthalpy of vaporization.)
Our formula tells us that if we want to make a cup of hot water in two minutes, we'll need a 700-watt power source. A typical microwave uses 700 to 1100 watts, and it takes about two minutes to heat a mug of water to make tea. It's nice when things work out![2]If they didn't, we'd just blame "inefficiency" or "vortices".
700 watts for two minutes is an awful lot of energy. When water falls from the top of Niagara Falls, it gains kinetic energy, which is converted to heat at the bottom. But even after falling that great distance, the water only heats up by a fraction of a degree.[3]\(\text{Height of Niagra Falls}\times\frac{\text{Acceleration of gravity}}{\text{Specific heat of water}}=0.12^\circ\text{C}\) To boil a cup of water, you'd have to drop it from higher than the top of the atmosphere.
How does stirring compare to microwaving?
Based on figures from industrial mixer engineering reports,[4]Brawn Mixer, Inc., Principles of Fluid Mixing (2003) I estimate that vigorously stirring a cup of tea adds heat at a rate of about a ten-millionth of a watt. That's completely negligible.[5]Tea loses heat a much higher rate than this. See: Ben Harden, Tea temperature vs. Time graph
The physical effect of stirring is actually a little complicated.[6]In some situations, mixing liquids can actually help keep them warm. Hot water rises, and when a body of water is large and still enough (like the ocean) a warm layer forms on the surface. This warm layer radiates heat much more quickly than a cold layer would. If you disrupt this hot layer by mixing the water, the rate of heat loss decreases.
This is why hurricanes tend to lose strength if they stop moving forward—their waves churn up cold water from the depths, cutting them off from the thin layer of hot surface water that was their main source of energy. Most of the heat is carried away from teacups by the air convecting over them, and so they cool from the top down. Stirring brings fresh hot water from the depths, so it can help this process. But there are other things going on—stirring disturbs the air, and it heats the walls of the mug. It's hard to be sure what's really going on without data.
Fortunately, we have the internet. StackExchange user drhodes measured the rate of teacup cooling from stirring vs. not stirring vs. repeatedly dipping a spoon into the cup vs. lifting it. Helpfully, drhodes posted both high-resolution graphs and the raw data itself, which is more than you can say for a lot of journal articles.
The conclusion: It doesn't really matter whether you stir, dip, or do nothing; the tea cools at about the same rate (although dipping the spoon in and out of the tea cooled it slightly faster).
Which brings us back to the original question: Could you boil tea if you just stirred it hard enough?
No.
The first problem is power. 700 watts is about a horsepower, so if you want to boil tea in two minutes, you'll need at least one horse to stir it hard enough.
You can reduce the power requirement by heating the tea over a longer period of time, but if you reduce it too far the tea will be cooling as fast as you're heating it.
Even if you could churn the spoon hard enough—tens of thousands of stirs per second—fluid dynamics would get in the way. At those high speeds, the tea would cavitate; a vacuum would form along the path of the spoon and stirring would become ineffective.
And if you stir hard enough that your tea cavitates, its surface area will increase very rapidly, and it will cool to room temperature in seconds:
No matter how hard you stir your tea, it's not going to get any warmer.
Second part to the interlude, by Jack. Thanks for spoiling us, you lovely lovely person<3
This week will feature our favorite GGaR warrior (apart from Jo of course): the Knight in Furs! And we have Jack to thank for! Remember him? He did a guest strip not that long ago, along with his friend Derek. Pretty neat style, huh?
There will be updates Wednesday and Friday as always, but since this "interlude" is in four parts, we'll just have to have an update on Saturday as well, won't we? So look for those! And thank Jack for me please. This way I can have a little break before starting a new chapter and breathe a bit. :)
Tests found tablet has problems
!['Will [ ] allow us to better understand each other and thus make war undesirable?' is one that pops up whenever we invent a new communication medium.](http://imgs.xkcd.com/comics/simple_answers.png "'Will [ ] allow us to better understand each other and thus make war undesirable?' is one that pops up whenever we invent a new communication medium.")