Why does your tongue stick to metal on a cold winter day but not to wood or plastic?

It is very interesting question related with my chemical engineering degree. If you knew about the conductive of materials, this question will be not really complicated for you. I had succesfully completed my mass and heat transfer class in college.

What is thermal conductivity ?

The quantity of heat transmitted, due to unit temperature gradient, in unit time under steady conditions in a direction normal to a surface of unit area.

Thermal Conductivity - k - is used in the Fourier's Law. Fourier's Law express conductive heat transfer as written:

Q = k A dT / s (1)
where
Q= heat transferred per unit time (W, Btu/hr)
A = heat transfer area (m2, ft2)
k = thernmal conductivity of materials (W/m.K or W/m oC, Btu/(hr oF ft2/ft))
dT = temperature difference across the material (K or oC, oF)
s = material thickness (m, ft)

Conductive heat flow occur in direction of the decreasing temperature since higher temperature are associated with higher molecular energy.

The metal, plastic and wood are at the same temperature, but the metal feels colder. That's because metal is better conductor of heat and it conducts heat away from your body faster than plastic or wood do. (2) The below is heat conductive of metal, plastic and wood at 25 oC

Iron.................................................................80 W/m.K
Wood oak........................................................0.17 W/m.K
Plastic foamed ( insulation materials)........0.03 W/m.K

References:

1. Fundamental of Heat and Mass Transfer 5th ed. by Frank P. Incropera and David P. Dewitt (2002)
2. Dr.Joe and what you didn't know: 177 fascinating questions and answers about the chemistry of everyday life by Joe Schwarcz (2003)

History of Cosmetic Science

When I was a kid, I am wondering how household products works? such as laundry bar soap. Because in my home country, people are using laundry bar soap in everyday life. When I take a shower, I like to read the label on my shampoo bottle listed by many compounds. Why was there many compounds and How all ingredients are works? Today, I had answer most of these questions because I am working in cosmetic industry. I will write in my blog a more in- depth discussion of each compound, structure formula and the role of the ingredients in products. The cosmetic science is founded way back in long time ago. It's hard to believe that around the 15th to the 10th centuries BC, Ancient Egyptians had cosmetic products. The products was made from natural materials such as iron oxide, copper and lead ore. They applied these products to their lower eyelids, rid of scratch marks and shrink wrinkles. Also they made bar soaps made from animal fat mixed with powdered lime. (1) Today, in the global market of the cosmetic industry is a multibillion dollar enterprise and there were many major companies is making all kinds of cosmetic products such as lotion, shampoo, deodorant, eye makeup, sunscreen lotion, skin care products and more.....


1.The history of Cosmetics- by Arden Millor ( A Vanity Fair magazine )

How to test methanol in Alcoholic beverages ?

Methanol formula is CH3-OH. Methanol is very toxic and when ingested in large amounts it can cause blindness and death. Smaller volumes can damage the brain. To determine the % of methanol in alcohol is very interesting subject.

• Methanol is flammable, volatile, clear colorless liquid. Odor of methanol very similar to drinking alcohol but slightly sweeter than ethanol. (1)
• There is several methods available for the estimation of methanol in alcohol beverages using Gas Chromatography ( GC) and Fourier Transform Infrared Spectroscopy (FTIS). You can find these standard analysis methods from website of AOAC (Association of Official Analytical Communities) and ASTM ( American Society for Testing and Materials). GC method is based on the retention time which is affected by temperature, pressure and flow of carrier gases.
• In laboratory simple test to determine of methanol in alcohol is using Fehling solution. Fehling solution contains copper (II) ions complexed with tartrate ions in sodium hydroxide solution. Equation can be written as:

2 Cu 2+(in comp) + 2OH- +2e--------------Cu2O+H2O

Two drops of the methanol is added to 2-3 ml of Fehling solution and the mixture is warmed gently in hot water bath for a few minutes. (2) The blue solution produces a dark red precipitate of copper oxide (I). Because methanol reduce the complexed copper (II) ion to copper (I) oxide.

gives the overall equation:

RCHO+ 2 Cu 2+..comp + 5 OH- ----------------RCOO + Cu2O + 3H2O

References

1. Material Safety Data Sheet Number: M2015 Prepared by: Environmental Health & Safety. (U.S.A.)
2. Vogel's Textbook of Practical Organic Chemistry 4th ed by Arhur I. Vogel (1987)

Which foods are rich in what elements?

98 % of the mass of the human body is made up of just five elements: oxygen, carbon, hydrogen, nitrogen and Calcium. Remaining 2 % is sparse sampling of the periodic table of elements. How human body get these elements. They come with the food we eat, the water we drink and the air we breathe. People asked me often times, which foods are rich in what particular elements? I have no easy answer this question but recent research has shown the following foods are rich in these elements :

• Foods with high levels of Magnesium are almonds, Brazil nuts, cashew nuts, soya bean, parships, bran, chocolate,cocoa, wholemeal bread, brown rice, cheese and brewers yeast
• Calcium in rich foods are almonds, corn tortillas, Brazil nuts, sunflower seeds and fish oil
• Potassium in rich foods are nuts, wheat bran, dried fruit, banana, potatoes, bacon, mashrooms and fruit juices
• Iron in rich foods are liver, wheat germ, meats, corned beef, iron-fortified breakfast cereals, red wine, baked beans, peanut butter, raisins, and eggs
• Zinc in rich foods are steak, pecans, dried milk, egg yolk, and oats
• Copper in rich foods are seafood's- oyster, crab, lobster, nuts, split liver, meat, butter,Brazil nuts, sunflower seeds, mushrooms and bran.
• Manganese in rich foods are pecans, whole wheat bread, oatmeal, cereal products, nuts, sunflower seeds, coconuts, peanuts, almonds, blueberries, olives corn, rice and tea
• Iodine in rich foods are any sea foods, cod, oysters, haddock, shrimp, herring, lobster, sunflower seeds, seaweed and sweet potatoes.
• Selenium in rich foods are Brazil nuts, any sea foods, milk, brown rice, butter, wholemeal bread and molasses.
• Molybdenum in rich foods are Liver, brown rice, oats, green beans and eggs

References;

Trace Elements in foods by Dr Myhill

Nature's Building Blocks by John Emsley

Uncle Sam want you to learn chemistry from Tumur's blog

Why pregnant women and children are need to eat foods rich in Calcium?

Everyone knows that Calcium is the most common element (1.5%) in the human body. Average adult men and women need at least 1.2 kg calcium of daily. Calcium nearly all of it found as the bones and teeth. Pregnant women and children are need to eat more calcium rich foods because calcium is help to growth of teeth and bones. Also, did you know that calcium most important role is in bodily functions, such as muscle contraction and protein regulation and keeps the PH of the blood stable and aids clotting.

The most recommended Calcium Rich foods are: Cheddar Cheese, milk, almonds, sunflower seeds, white bread, leafy green vegetables and Vitamin D in fish liver oil as well.

How much water should you drink per day ?

Eveybody knew that the water formula is two hydrogen atoms bonded with one oxygen atom. 65 % oxygen and 10 % hydrogen are predominantly found in water, which makes up about 60-70 % of the body by weight. It's practically impossible to imagine life without water. When your body doesn't have enough water, that's called being dehydrated. A bad case of dehydration can make you sick. Not only does water fight dehydration, but it's awfully refreshing and has no calories.
How much water should I drink per day? A sample question with not easy answer.
The general recommendation is 8×8 oz cups of water daily. A good guideline below as promoted by Paul Chek (world-renowned expert in the fields of corrective and high-performance exercise kinesiology). We can calculate the amount of drinking water that we need on average each day. This is calculated on our body weight in kg’s, divided by 0.024.
For example: An 80 kg person would require 3 1/3 litres per day (80 kg divided by 0.024 = 3.3 litres per day). This amount of water is the minimum you need a day to assist your cells functioning optimally.This will increase to at least 1 litre if the day is hot or we are doing exercise.

How much water do you drink in a given day?
Leave a comment!
Looking forward to hearing from you,

Major Elements in the human body

The Scientists has discovered more than 60 chemical elements in the human body.The human body requires 25 elements if it is to function properly. These are called the essential elements and are listed in the table below as fractions of the total body mass.





Raw Data from which this table was made from: Nature's Building Blocks AN A-z Guide Elements by John Emsley (2001)

Fraction of total body Elements
61 % ...........of Oxygen
23 % ...........of Carbon
10 % ...........of Hydrogen
2.6 %......... .of Nitrogen
1.4 %........... of Calcium
1.1 %........... of Phosphorus
0.2 %........... of Sulfur
0.2 %........... of Potassium
0.14 %......... of Sodium
0.12 %..........of Chlorine
0.027 %........of Magnesium
0.026 %.......of Silicon
60 p.p.m.......of Iron
37 p.p.m........of Fluorine
33 p.pm........ of Zinc
1 p.p.m......... of Copper
0.2 p.p.m...... of Manganese
0.2 p.p.m...... of Tin
0.2 p.p.m...... of Iodine
0.2 p.p.m.......of Selenium
0.2 p.p.m...... of Nickel
0.1 p.p.m.......of Molybdenum
0.1 p.p.m ......of Vanadium
0.03 p.p.m.....of Chromium
0.02 p.p.m.....of Cobalt

Units of p.p.m (parts per million)

Chemistry in Every day Life

Chemistry is the science that concerns the composition, structure and properties of matter. All the matter that you are likely meet in your everyday life is made of Chemicals or a mixture of chemicals: Sun, Air, food, plants, animals, people, and rocks are all chemicals. For example: the sun contains 94 % hydrogen, 6 % helium and less than 0.2% all other elements. The atmosphere contains nitrogen, oxygen and other elements. The human body is more than 60 % of water, 65% Oxygen, 18% Carbon, 10% Hydrogen, 3% Nitrogen..... other elements.Chemical reactions are part of everything you do from breathing and eating to thinking. Science of Chemistry will help you better to understand the world around you and how things works.

• How many elements in the human body?
• How much water you should drink per day?
• What's the food elements?
• What's difference between sports drink and regular water?
• What's difference between hard and soft water?
• How detergents works? Can I use laundry detergent instead of dish washer?
• How is bleach works?
• What's soap?
• Why carbon monoxide dangerous for your health?
• How can I buy better gasoline in my car?
• What's chewing gum?
• Why people need to use sunscreen lotion?

The following days I will explain each subject separately.

Thank you for reading.

.

Free Museum Days 2009 in USA

International museum day has been celebrated since 1977 all over day world. In USA, the most of museums have Free Admission on September 26, 2009 because of Museum day 2009.

Find out Free Museum admissions in your area from the following website. http://microsite.smithsonianmag.com/museumday/index.html....

Enjoy your free Museum Admission !!!

Chemistry in my life

I have been learning in Chemistry since at age 14. I studied chemistry 4 years in high school and 8 years in college. After these long years, I discovered you never know yourself until you tested. Tested mean is to work in real a job. In my blogs, I want to shear my knowledge of chemistry to people and I want to bring chemistry to real life as close as I can. Chemistry is big Science. It is impossible to explain everything at once. At least I am try to explain how things works. Science answer one question, it usually raises other question. Never ended.......................

Continue.............

Money saving tips

Every day, most of people has financial problems. If you didn't think about how to save money from regular daily basis, you never save money. Even you had good paying a job.

Here is 6 tips how to save money grocery shopping, gas and phone.

1. Before buying the gas and phone, people need to shop round in the Internet. If you have Internet, it will be takes few minutes. The following website help you how to find cheaper phone and gas near by your home. http://www.billshrink.com..,


2. When you buy gas from gas station you need take in attention buying food and items. Because these items cost you double in gas station. For example: bottle of water cost you $1.50 in gas station. Case of water $3.25 in Costco. You can keep the case of water in your car and when you thirsty you can drink any time.


3. If you buy Sunday Chicago Tribune newspaper every Sunday, you will be save some amount of money from coupons. The newspaper cost you $1.99 but you can find ton's of different coupons from this newspaper.


4. If you have time instead of going out small grocery store, go to Sam's club and Costco. Because most of small business owners buy items from Costco and Sam's club and selling to you double prices.


5. When you pay your phone bill, instead of traveling to phone store. You can pay online using your credit card.


6. Final saving money advise from me, you can stay home, if you can. Even your friends ask you go out. If you go outside, you will spend money on ice cream, coffee and red bull, monster ..............double prise!!!!!!!!!