What is Weight? Simply put, an object's weight on Earth is the force of gravity pulling on the object. The force of gravity pulling on the object — or the object's weight — is proportional to the masses of both the Earth and the object. So, if the object has more mass, its weight will be greater. Also, if the mass of the Earth somehow increased, the object's weight would
As discussed in the unit on gravitational forces, like all forces, gravity is a mutual force. This means that the force of gravity on an object on Earth is equal to (but opposite directions from) the force of the object on the Earth. (This idea is shown above, where the forces are equal but in opposite directions.)
Calculating object weight. The weight of an object here on Earth is equal to the mass of the object times the acceleration due to gravity on Earth, or g, which is about 10 m/s2:
Weight of object (on Earth) = mass of object * 10 m/s2
The direction of the force of weight is straight down (toward the center of the earth).
Weight on other planets. In general, the weight of an object on any planet (or moon), etc., is proportional to the masses of both the object and planet (or moon). So, if the object has more mass, its weight will be greater. Also, if the mass of the planet (or moon) is greater, the weight of the object will be greater.
So, your weight on the biggest planet (Jupiter) would be your weight here on Earth. But you would weigh less on Mercury or Mars than on Earth because these planets are less massive than the Earth.
The weight of an object on another planet (or moon) is equal to the mass of the object times the acceleration due to gravity on the planet (or moon):
Weight of object (on planet/moon) = mass of object * acceleration due to gravity on planet/moon
The acceleration is greater for more massive planets (or moons).
Mass is constant. But, of course, your mass would not change. You would still look the same here on Earth and on the other planets, because the amount of "stuff" you are made of would not change.
***Note for Teachers: You can access more information about this website and find other resources for science inquiry on the ISP Tutor website.
©2022 Klahr Lab. All Rights Reserved
The TED project was funded in part by the Institute of Education Science (IES), Grant R305H060034, and in part by the National Science Foundation, Grant SBE035442. The ISP Tutor project was funded by IES, Grant R305A170176.
The research reported here was supported by the Institute of Education Sciences, U.S. Department of Education, through Grant R305A170176 to Carnegie Mellon University (Klahr Lab). The opinions expressed are those of the authors and do not represent views of the Institute or the U.S. Department of Education.