Column: Science lessons really explain a lot

Published 5:27 pm Friday, December 20, 2019


Coffee with Mimi

Way back in 1687, Sir Isaac Newton of England put forth three simple laws to explain motion. In the world of science, these rules are so significant that virtually every student is compelled to memorize and experiment with them to understand the relationship between objects and motion on the earth.

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I took a physics class or two in high school, which, by some reckoning, wasn’t too long after the laws were published. The experience was so memorable, I can nearly quote the laws to this day. The laws were meant to explain relationships in the context of provable scientific facts in an age when such thought was a bit new and at times controversial. 

High school science students have no idea these three little laws actually explain many  activities in real life and that remembering them will save a great deal of time and anguish in their future endeavors.

Take leaf management, for example.

While Sir Isaac Newton is the inspiration for this discussion, let’s not forget Galileo’s contribution to the fact pile. Leaves fall from tree branches to the ground. You can calculate the height of the tree branch, take into consideration the size and density of the leaf and you may have some understanding of the depth of the task ahead of you before you get to work.

However, you get there intellectually, you will most certainly have a real life pile of leaves on the ground in your yard. It is generally accepted that those leaves should not remain on your yard.  Neighborhood conversation is full of leaf discussions from October to December. Depending on the types of trees you have, the issue is more pressing earlier rather than later. After that, we give up as the laws of weather have ruled.

Along about November, when the leaves are falling at a prodigious rate, human activity begins. Tools are gathered and time is allotted for the task of leaf removal.

Newton’s first law tells us that every object in motion will remain in motion unless an external force acts on it; if only. What Isaac forgot to thoroughly explain is that just about anything can and does act as an external force on the object. In the case of leaves, my rake full of leaves, when pushed toward the curb where they will be vacuumed up by the big leaf sucking machine, will not continue of their own volition to the curb because they are impeded by other leaves and the blades of grass naturally occurring in the yard. 

And, let’s not forget the wind. One little detail about the law is that the object will move in a straight line unless — yep, some other force shoves it off course. In the case of leaves, it is always backwards, away from the curb. 

The scientific law is real. Sir Isaac was trying to be kind by not giving us the whole truth. He probably had a teenage leaf raker in the house and didn’t want to get too much in the weeds with scientific theory when chores were passed out.  

The second law states that force equals mass times acceleration; doesn’t it though. Leaves weigh just about nothing. Raking vigorously gets the leaves moved minimally because they don’t contribute to the effort themselves, due to their relative weightlessness.  

The charming sight of brightly colored objects drifting to earth in October should put a chill in a leaf owner’s scientifically informed heart. Isaac proved it. This law applies to leaf blowing, as well. The truth of leaf blowing is that it is most effective when combined with a second and simultaneous effort of raking. This requires additional persons supplying effort. Apply that condition to the law. And besides that, leaf blowers are noisy.

Newton didn’t leave it there and rounded out his theorizing with a third law. For every action in nature, there is an equal and opposite reaction; he got that one right. The example most often cited in class was the one where a kid jumps up and down in front of the room. Clearly, the demonstrator does not go crashing through the floor into the history class in the room below.  Lesson learned. 

The classroom floor exerted an opposite force on the student’s action equalling whatever pressure he put on the floor; this worked every time. Didn’t matter if it was a big kid or a smaller one. The students neither crashed through the floor, nor were catapulted into space. 

The law also works in leaf raking. It is true. A leaf, when raked toward the curb, will not sail off into space, maybe into the neighbor’s yard, but it will stay in the neighborhood. It will not blast a hole in the street pavement when it is finally raked to the curb. 

However, Isaac didn’t exactly have the more practical applications and reality of this one factored in. Whatever effort exerted in raking leaves will result in an equal amount of pain and exhaustion on the part of the leaf raker. 

I sure wish Sir Isaac Newton had an explanation for recovery of an object from sustained effort.