# High School Physics Lessons - Animal Sizes - Practical

## Animal Size and Scale

Considering how large some things are (like mountains and planets), isn't it surprising that most advanced animals are all from several inches to about 20 feet in size? Do you think that there might be some reason for that? You betcha!

Consider a moderate sized dog, like a Beagle. One that is about 16" tall (measured at the shoulders), will likely weigh 40 pounds.

What if we thought about somehow "magnifying" him to ten times his size. He would be the same overall appearance, just bigger!

Now think about the bones in his legs. How big would they be, compared to how big the same bones are in normal-sized dogs? The bones would be ten times as thick, front to back, and ten times as thick, side to side. Therefore the AREA of the bone will be 100 times as big.

OK. Now let's think about the size of his body. It would be ten times as big, front to back, ten times as big, side to side, and ten times as high, meaning that there will be 1000 times as much of him, as compared to a regular-sized dog. It turns out that the density of all living materials is all pretty similar (because it's all mostly water!) This means that because his body is 1000 times as much, then his WEIGHT will be a thousand times as much, too.

What's all this mean? Well, he has legs that are a hundred times as strong as those of a normal-sized dog, but his weight of 1000 times as much has to be supported by those legs. So, relatively speaking, his legs would have to be supporting ten times the equivalent weight of a normal-sized dog.

Imagine how active a Beagle would be if you strapped 360 pounds of weight to his back. He would probably not even be able to walk! His legs might just crush under all that weight.

An African Elephant is the largest land animal that exists. The largest ones happen to be about 10 times the height of the normal-sized dog we talked about above. They weigh about 16,000 pounds. Have you ever wondered why they have such thick legs? Now you know, because the bones and muscles in there have to be much thicker than if it was a smaller animal.

Now that you have read this, please look at High School Physics Lessons - Planets are Round - Practical to see another application of this principle.

## Useful Applications of Physics Knowledge

Most adults HATE the concept of Physics. If they could, they avoided it in High School and College. If they HAD to take it, Physics seems to represent a traumatic experience in their lives.

This is the case primarily because no one (and no textbook) showed them the incredible usefulness a moderate knowledge of Physics can be.

This series of lessons is meant to correct that situation. Students in High School or College Physics should be able to benefit from and EVEN ENJOY (!!) these Physics lessons. The lessons should help clarify the usages of a lot of those dry subjects and equations the teacher or professor tries to ram down your throat. These lessons are freely made available to teachers and professors for use as they desire, either on the InterNet or in the classroom.

(The preceding paragraphs appears in each lesson, in the event that someone happens to find a single lesson from this series as a result of a search-engine search.)

The High School Physics Lessons - Practical A of this series is:
http://mb-soft.com/public/phys0.html

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C Johnson, Theoretical Physicist, Physics Degree from Univ of Chicago