Post: Universal Gravitation
In the same century, Newton didn’t only discover gravity but also a law called universal gravitation. Here, I will explain more about gravitation and how it happens right in front of us even when we aren’t looking. The law of universal gravitation explains many questions such as how the planets orbit the sun. You will find more about gravity in this post, as well as how the formula works.
What Is Universal Gravitation?
In the 1600s Isaac Newton discovered a law that every object attracts every other object. That is called universal gravitation. So technically, you are attracting everything around you including the device you are reading this on, and the device is attracting you. You aren’t seeing a “pull” because the force is too weak. Gravity works better with heavier objects. This law also explains why the planets orbit the sun: the sun is heavier than all the other planets and attracts them.
Formula for Gravitation
Now I will explain the formula of gravitation, $F = G \frac{m_1 m_2}{r^2}$. On the top of the fraction you can see that we multiply the masses of the two objects - this is why I said the lighter an object is, the weaker the force is. If the masses are smaller you will get a smaller product. Then, we divide the product by the distance squared. The force becomes weaker if the objects are far from each other. Finally, we multiply by the gravitational constant. And then you get the gravitational attraction!
Cavendish’s Experiment
In the late 1700s, Cavendish did an experiment to find the density of Earth, which led to calculating the gravitational constant. The setup was simple: he used a rod with two balls at each end, and it had a string keeping it up. Then, he put two larger balls each on the left or right of the smaller balls. If every object attracts every other object, then the smaller balls will go toward the larger ones, twisting the string at the top. Then, he calculated the twist of the string. This experiment was a great demonstration of universal gravitation.
Conclusion
This post showed you more about gravity and the pull between objects. It also showed you how it works not only with the planets in the solar system but also with objects on Earth such as the balls from Cavendish’s experiment. The formula for gravitation showed that the gravitational attraction is stronger if the objects are closer and if they are heavier. That concludes this blog post. I hope you enjoyed reading!
