Attached is the Answer Key for the quiz.
Mr. Sack
http://www.mrsack.info/dl/calc_Chap3-1_3-3.pdf
21Nov
Algebra Turkey Question
Similar to the Calculus Turkey Question….but can be solved with Algebra. Hint: Use a slope.
A roasted turkey is taken from an oven when its temperature has reached 185oF and is placed on a table in a room where the temperature is 75oF.
a) If the temperature of the turkey is 150oF after half an hour, what is its temperature after 40 min?
b) When will the turkey cool to 90oF?
21Nov
Roasted Turkey Calculus Question
A roast turkey is taken from an oven when its temperature has reached 185°F and is placed on a table in a room where the temperature is 75°F.
(a) If the temperature of the turkey is 150°F after half an hour, what is the temperature after 40 minutes?
_____°F(b) When will the turkey have cooled to 100°F?
____ minutes
_____°F(b) When will the turkey have cooled to 100°F?
____ minutes
Happy Thanksgiving
21Nov
The Physics of Cooking A Turkey
The science of cooking a turkey:
As you cook the turkey, muscle fibers contract until they begin to break up at around 180 degrees Fahrenheit. Bonds within the molecules begin to break down, causing proteins to unravel, and the dense muscle meat to become more tender. Collagen in the bird (one of three protein fibers that attaches muscles to the bone) breaks down into softer gelatin molecules as it unwinds.The dryness of a turkey is a result of muscle proteins coagulating within the meat, which can result if it is cooked too long.
Temperature differentials in cooking a turkey:
Part of the problem, as described above, is that the different nature of the light and dark meat in a turkey result in different rates to reach the coagulation of the muscle proteins. If you cook it too long, the breast meat has coagulated; if you don’t cook the bird long enough, the dark meat is still tough and chewy.Harold McGee, a food science writer, indicates aiming for 155 – 160 degrees Fahrenheit in the breast (which concurs with the overall temperature indicated by Roger Highfield), but you want 180 degrees or above in the leg (a distinction Highfield does not address).
Heating differentials in cooking a turkey:
Since you ultimately want the breast and legs to be different temperatures, the question is how to successfully accomplish this. McGree presents one option, by using ice packs to keep the breast of the bird about 20 degrees lower than the legs while thawing, so that the legs get a “heat start” on the cooking process when they’re put in the oven.Alton Brown, of Food Network’s Good Eats, once presented another way to establish different heating rates, using aluminum foil to reflect heat away from the breast, thus resulting in the legs heating faster than the breast. His current roast turkey recipe on the Food Network website does not include this step, but if you watch the related videos, it shows the steps involved in using the aluminum foil
Cooking thermodynamics:
Based on thermodynamics, it is possible to make some estimations of cooking time for a turkey. Considering the following estimations, it becomes fairly straightforward:
- Assume the oven maintains a constant temperature throughout.
- Assume the thermal diffusivity is independent of temperature and time.
- Assume the turkey is so plump that it can be estimated as a sphere.
You can then apply the principles of Carlaw & Jaeger’s 1947 Conduction of Heat in Solids to come up with an estimate for the cooking time. The “radius” of the hypothetical spherical turkey falls out, resulting in a formula based solely on mass.
Happy Thanksgiving Everyone….
Source: About.Com
06Oct
iSad – Steve Jobs 1955-2011
The world has lost one if its true innovators. Steve Jobs wasn’t only an innovator in consumer electronics (iPod, iPad, iPhone) and computers (iMac, Macbook, etc.), he also changed the way we buy and listen to music. He also changed the way we watch movies with his technological breakthroughs at Pixar. My condolences to the Jobs family and all who knew him.
I actually met Steve Jobs in 1984 at the COMDEX computer show at a party when Apple (and I) were very young. I had developed voice recognition software for the Apple II while in college and I was at IBM for two years developing graphics software for them.
He was a pretty animated and interesting guy and always said what was on his mind.
I had an opportunity to leave IBM go to work for Apple shortly after our meeting, but decided to stay with IBM.
26Sep
Cool Derivative Calculator
Here is a cool derivative calculator: http://www.webmath.com/diff.html
26Sep
Dervative Table
Here is very good list and explanation of derivatives of trig and log functions. We will also be going over the chain rule next week.
23Sep
Another Way At Looking At Subtracting Negative Numbers
“How do you go from ‘ – (–16)’ to + 16 ?”
Imagine that you’re cooking some kind of stew, but not on a stove. You control the temperature of the stew with magic cubes. These cubes come in two types: hot cubes and cold cubes.
If you add a hot cube (add a positive number), the temperature goes up. If you add a cold cube (add a negative number), the temperature goes down. If you remove a hot cube (subtract a positive number), the temperature goes down. And if you remove a cold cube (subtract a negative number), the temperature goes UP! That is, subtracting a negative is the same as adding a positive.
Now suppose you have some double cubes and some triple cubes. If you add three double-hot cubes (add three-times-positive-two), the temperature goes up by six. And if you remove two triple-cold cubes (subtract two-times-negative-three), you get the same result. That is, –2(–3) = + 6.
There’s another analogy that I’ve been seeing recently. Letting “good” be “positive” and “bad” be “negative”, you could say:
good things happening to good people: a good thing
good things happening to bad people: a bad thing
bad things happening to good people: a bad thing
bad things happening to bad people: a good thing
Source: Purplemath.Com
22Sep
Top Colleges For Entrepreneaurs
Here is a great article that discusses the top colleges where you can learn how to start your own business.
The Top 50 Entrepreneurship Programs
21Sep
Entrepreneaur Magazine
To get some ideas for your Economics project and to see what other people are doing to start up businesses, check out Entrepreneaur Magazine. There are a lot of interesting articles on all types of businesses and the people who started them.
This month, there is a great article on starting a business in a recession.
20Sep
Calculus Test Suggestion
Hint: Make sure you understand the concepts of the Tangent Line Problem and the Area Problem. Also understand the concepts of Continuity and Discontinuity for tomorrow.
19Sep
Economics Project Posted
HI Class….
As we discussed today, the Economics Project is up on MrSack.Info.
Here is the link: http://www.mrsack.info/dl/2011_project_business_plan.pdf
It is due on October 3.
18Sep
Precalc 4.3 Answers
16Sep
Create A Business Plan Project
I have uploaded the Project Rubric for the Create A Business Plan project. It is due October 3 and counts 10o points towards your grade. Presentations will be the week of October 3.
You can download it here: http://www.mrsack.info/dl/2011_project_business_plan.pdf
16Sep
Calculus Continuity Help
Hi Class….
Here is another discussion and example of Continuity that may be helpful. It is in Spark Notes.
Spark Notes Discussion on Continuity
15Sep
Horror Movies!!!
NetFlix (NFLX) is down 15% today after losing 1 Million subscribers after their price increase. NFLX is $175 per share this morning…down from $300.00 in July.
15Sep
Intro to Logarithms
Here is a good tutorial on Logarithms. I suggest you check it out if you need additional help and can’t come in after school or are stuck at home.
14Sep
Extra Help Reminder
Don’t forget I am available EVERY DAY after school for extra help and many H periods. There is never any excuse for not understanding something. Just drop by my classroom during those times and together we can get you back on track if you are stuck or lost on a concept or topic.