An athlete throwing a ball. A gymnast tossing a baton. A chef making pizza dough. A child playing
with a paper airplane. What do these things all have in common? Do you know in each of these
instances, a particular scientific principle is at work? Something amazing happens when you throw an
object into the air. Have you guessed what the phenomenon is? No matter how hard we throw an
object, it will always come back to the ground. This scientific principle is called gravity.
You may not think about gravity often or consider it noteworthy because it is so very, very common.
You've probably experienced it hundreds or even thousands of times since you were born
without even realizing it. For thousands of years, people knew that an object going up
would always come back down. It wasn't until Isaac Newton watched an apple fall from a tree
that the question of why was posed. Newton observed that an apple shaking loose from a tree
will always fall down, not upward or sideways. Seeking to better understand what was happening,
Newton began to wonder what caused objects to fall to the earth.
Isaac Newton developed a new theory he called the Law of Universal Gravitation. This law states that
every object is attracted to other objects in direct proportion to their mass.
What does that mean? We all experience the effects of gravity pulling us down towards the earth in
the same way a ball thrown into the air falls back down. However, the Earth is not the only object
that has a gravitational pull. In fact, every object in our universe has a gravitational pull,
and the bigger the mass of the object, the larger its gravitational pull. Since the Earth is a very,
very large object and always has the highest mass of any object within reasonable distance to us,
we feel its gravitational pull more than any other object around us. Gravity is working on
everything, all the time. There is a gravitational pull between the couch in your house and the lamp.
There is a gravitational pull between a tree and a bird in the sky. There is a gravitational pull
between a honey bee and a flower. Look around at any two objects and you are seeing
gravity at work. However, these gravitational pulls are so small that we don't even notice them.
Because the size and mass of each of these objects are minuscule when compared to the Earth,
because the Earth has so much mass, the only gravitational pull that we typically notice is
the pull downward toward the center of the Earth. Interestingly, the farther apart objects are,
the less gravity affects those objects. For example, as an astronaut launches into space,
the gravitational pull between the astronaut and the earth becomes less and less.
Gravity is not limited to our earth, though it also plays an important role in the universe.
Remember, the more mass an object has, the stronger the gravitational pull it has on
other objects. The sun is by far the object with the most mass in our solar system,
and all the planets orbit the sun because of its gravitational pull.
We often take it for granted in our day-to-day lives, but gravity is a complex and fascinating
force. The principle of gravity keeps the planets in our solar system in orbit
around our life-giving sun. This same force causes ripe apples to fall to the ground.
But when you jump, it's gravity that returns your feet to the surface of the Earth.
God created a world where we have just the right amount of gravity to keep us grounded, but also
allow us to move easily. The next time you throw a ball or watch a piece of fruit drop to the ground,
take a moment to marvel like Isaac Newton did at the fascinating force that is gravity.