January 14, 2010

It's “Hot Foods Month”!

In the Northern Hemisphere, it tends to be cold in January. For many, this January in particular has been really cold. Perhaps that's why January has been declared:
Hot Tea Month,
Oatmeal Month, and

Mmm, sounds good, doesn't it? It would be so nice to spend all day inside, cozy and warm, drinking hot tea and eating hot oatmeal and soup.

Try this no-sugar-added recipe for Apple-Snapple Oatmeal. (It's nothing to do with the product “Snapple.”)

Or how about this Amish Baked Oatmeal?

Here is a rec
ipe for Italian Sausage Soup, and here is a vegetarian Black Bean and Salsa Soup.

Keep Warm!

You have probably heard the term “warm-blooded.” Although sci
entists don't use the term anymore (it is quite vague), most of us “get” that warm-blooded animals are able to keep their own body temperatures relatively steady, no matter what temperature their surroundings are.

Different a
nimals use a variety of ways to regulate their temperatures and withstand the cold. Take this quiz to see how hot your temperature knowledge is.

1.Tortoises are cold-blooded, so they need to be wrapped in a blanket to stay warm at night. True or False?

2.Dinosaurs are reptiles, so they are cold-blooded. True or False?

3.Bears, like other mammals, are warm-blooded. Still
, many species hibernate during the coldest part of the year. True or False?

4.In general, warm-blooded animals needs 5 to 10 times as much food as cold-blooded ones of the same size. True or False?

5.Shivering causes an animal to become colder. Tru
e or False?
6.Which of the things below help us humans to keep warmer? (There is more than one correct answer.)

A. Dressing in layers

B. Getting out of the wind
C. Drinking hot liquids
D. Keeping the head covered
E. Sweating

ANSWERS and Explanations:

1.false. Blankets and sweaters and other cozy items help ke
ep warm-blooded (endothermic) animals warm in cold air because they insulate the animal from the colder environment in the same way that a thermos bottle helps to keep coffee hot. However, if you put cold or room-temperature coffee into a thermos, it's not going to get hot! In the same way, a cold tortoise isn't going to heat up with a blanket or a sweater. The blanket will soon reach the outside temperature, as will the tortoise. In order to warm up the tortoise, something like a heat lamp is called for.

2.false. All reptiles alive today are cold-blooded (ectothermic),
but the dinosaurs did evolve into the warm-blooded birds. So at some point, some of the creatures, at least, did begin to regulate their body heat. Scientists think that different dinosaurs evolved different mechanisms of heat regulation, but most scientists think that most dinosaurs were warm-blooded.

3.true. Most mammals are fully endothermic, including bears, but different mammals have different strategies for surviving cold temperatures. One of those strategies is hibernation, during which the body temperature may drop as much as 50 degrees Fa

4.true. There are advantages and disadvantages of being warm-blooded. One of the advantages is that endothermic creatures can remain active no matter what the temperature is, but the cost for our higher metabolism is that we need more food than cold-blood
ed animals—5 to 10 times the food of a ectothermic animal of the same size.

.false. Warm-blooded animals (including humans) shiver when they are cold in order to warm themselves. Movement of any kind creates heat, which is why people stamp their feet and rub their hands when they get cold.

6. A, B, and D help keep us warm.
C makes us feel warm, but doesn't necessarily make us warmer.

E cools us off.

A. Layers keep us warm because a small layer of air is trapped between each layer. Like the air between the two sides of a thermos bottle, this air acts as insulation to prevent heat loss.

B. Wind across a surface causes heat loss from that surface,
and the faster the wind, the greater the heat loss. If the air is 50 degrees F and there is wind, we FEEL colder than 50 degrees with no wind, and our bodies lose more heat, as well. That's why meteorologists and weather reporters talk about the “wind chill factor.”

C. I read explanations from doctors that claimed two seemingly conflicting things. First, hot drinks can slightly increase our core temperature, thus keep us warm. However, hot drinks make us feel warmer because the hot liquid increases blood flow to the skin--but there, the heat can be lost, which makes us slightly colder.
D. It is a bit of a myth that we lose most of our body heat through our head, according to research, but there can be a significant amount of heat loss from the head when you are at rest, and way more when you are exercising or shivering. So keeping the head covered is an important key to staying warm.

E. Sweat evaporating off the skin is a major way in which many animals, including humans, stays cool.

Here are some cool infrared photos. Notice the difference between the cold-blooded creatures and the warm-blooded humans holding them!

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