April 4, 2017
You can’t talk about forces and motion without talking about Isaac Newton. His three Laws of Motion were published more than 300 years ago, and yet their basic concepts—inertia, acceleration, momentum, and mass—are still the standard for how we discuss forces and motion today. The laws may have been refined over the years (most famously by Einstein) but they still reign as incontrovertible scientific laws. We couldn’t send the Hubble Space Telescope into orbit without Newton.
While there may not be much NEW about Newton’s Laws, there is still plenty to say about how they affect the world around us. Read on for some interesting news reports related to forces and motion. Let us know if you find an article you’d like us to post!
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May 28, 2011
by: Matthew Morris
Newton was a revolutionary thinker of his time. He is responsible for the three laws of motion that we still use today;
1. Objects that are not in motion remain stationary unless acted upon by another force.
2. There is a direct relationship between the force acted upon the object and the mass of that object times the acceleration the object feels (F=ma).
3. For every action there is an equal and opposite reaction.
Nobody before Newton could explain why objects acted the way they did, but with these three laws he quantified movement in terms everyone could understand.
But there was a problem with his theory; if all motion had to be caused by some force acting on it, then why do objects fall towards the earth when you release them from a fixed position? This free falling object was in fact free, meaning free of outside forces acting upon it (besides wind resistance). There were no visible forces acting upon that object. So why do they move downward if nothing is acting on it? But Newton explained this motion with gravity. He said that gravity is a force that the earth has upon all objects, something invisible that pulls us down at all times at a constant acceleration. There is a myth that the way Newton thought of the idea of gravity was when he was thinking about it under an apple tree when an apple fell on Newton’s head and at that moment, he figured out that there must be a force pulling the object down. This is also why apples are used to demonstrate Newton’s force, but no one knows definitively if the myth is true or not. Read the rest of this entry »
March 25, 2010
by: Martin Sagendorf
We often think we see forces. However, in reality, we only see the results of forces. To understand forces we must believe in Newton’s Third Law. It states that all forces can only exist in opposite pairs and be equal in magnitude. And… what is very interesting is that Newton’s Third Law does not stipulate that the forces be of the same kind.
Also, by Newton’s Second Law: If the (net) forces are equal, there will be no accelerations (Fnet = ma = 0)… in other words… equal and opposite (net) forces create a state of equilibrium. An interesting example of equal and opposite (and unlike-type) forces is that exhibited by a combination of opposed magnetic fields within a gravitational (force) field. These two different (types) of fields interact purely as ‘force fields’ – only their forces matter… not their types.
The Cosmic Magnetic Puzzle exemplifies a combination of such forces: a barbell containing two ‘donut’ magnets supported in mid-air above stationary pairs of magnets – with an additional pair of donut magnets maintaining the horizontal location of the barbell. Read the rest of this entry »
July 31, 2009
by: Norman Barstow
When the National Research Council produced the National Science Standards in 1995, they did so without including sets of lesson plans nor did they design them as part of a standard curriculum package. They were written to be used as goals for our students’ achievement in science.
In my classroom I always used the National Standards when designing my lessons, and they were always clearly represented in the objectives I set for my students. I have found that the topics of Force and Motion, as well as Air, (as part of a weather unit), can be easily taught using balloons to demonstrate the concepts of each. Read the rest of this entry »