Light for Flight
But How Much do Satellite Transmitters Weigh?

Question: If you wore a backpack that weighed 2% of your body weight, how heavy would your backpack be?

"I think Journey North is asking this question so that people know how an eagle feels when it is wearing a backpack," said Chris, Bill, Jacob, and Rhyan from New York. "If I wore a backpack, and if I weighed 120 pounds, my backpack would weigh 24 pounds." (

Answer: Well, luckily for the eagles, their backpacks aren't as heavy as the boys calculated. Just a small mistake with a decimal would mean a terribly heavy backpack for an eagle!

The backpack for a 120 pound person would weigh only 2.4 pounds. (The 24 pounds the boys calculated would be 20% of the 120 pound person's weight.) To calculate 2% of that weight, multiply by .02 and you get just 2.4 pounds. (.02 x 120 = 2.4 pounds) Aren't you relieved to know that eagles don't have to carry a backpack that's 20% of their weight?

Try This!
Fill a backpack until it weighs 2% of your body weight to see how it feels.

As the boys in New York point out, this is what people--including the scientists--are concerned about. Scientists do not want their research to interfere with the life of the eagle. This is for humanitarian reasons, but also because they don't want their research to be affected. The scientists want to learn about NORMAL eagle behavior. How many ways can you imagine that the backpack might cause ABNORMAL behavior? The scientists must always have this in mind when they design their research--and also when they interpret the results.