Solved

gravity demo

Posted on 2012-04-02
3
331 Views
Last Modified: 2012-04-03
Hello

Do you know of any demos I could use in a classroom which involve pupil participation to show that gravity decreases with distance or to show that gravity is a force of attraction between 2 objects.

The emphasis is on the use of volunteers to show very basic gravity concepts

thanks
0
Comment
Question by:andieje
3 Comments
 
LVL 27

Assisted Solution

by:d-glitch
d-glitch earned 167 total points
ID: 37798371
I'm not sure there is much you can do in a classroom.

The website lets you calculate g as a function of location:  
     http://www.physicsclassroom.com/class/circles/u6l3e.cfm

At the top of Mt Everest, g is only 2% less than at sea level.

If you were to try to measure g (with a pendulum for example) in the basement and on the roof, you would be hard pressed to see any difference.
That doesn't mean you shouldn't try.

Another classic gravity experiment is the Cavendish experiment, which requires enormous masses and precise measurements.  Not easy in the classroom.
http://en.wikipedia.org/wiki/Cavendish_experiment
0
 
LVL 27

Assisted Solution

by:aburr
aburr earned 166 total points
ID: 37798620
The distance relation is too small for easy illustration, especially with people.
The demonstration essentially measures the Newtonian G (not g).
As mentioned, the Cavendish experiment used large masses (they were moved on rails with mining carts)
You can easily illustrate the increase in attraction with increase in mass (with a spring).
One of the difficulties is the large size of the earth. If you double the distance of the mass from the surface of the earth., you have changed the r in F = GmM/r^2 by only something like
0.00001%
0
 
LVL 84

Accepted Solution

by:
ozo earned 167 total points
ID: 37799310
Since gravity is so weak, instruments sensitive enough to demonstrate this in a classroom may be prohibitively expensive,
But electrostatic forces decrease with distance in the same way, so that might provide an easier demonstration of the same 1/r^2 law
http://www.engr.uky.edu/~gedney/courses/ee468/expmnt/coulomb.html

Or, of you want to observe the orbits of planets and moons, you might demonstrate Kepler's law's and relate that to 1/r^2 gravity.
0

Featured Post

NAS Cloud Backup Strategies

This article explains backup scenarios when using network storage. We review the so-called “3-2-1 strategy” and summarize the methods you can use to send NAS data to the cloud

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

A Guide to the PMT, FV, IPMT and PPMT Functions In MS Excel we have the PMT, FV, IPMT and PPMT functions, which do a fantastic job for interest rate calculations.  But what if you don't have Excel ? This article is for programmers looking to re…
How to Win a Jar of Candy Corn: A Scientific Approach! I love mathematics. If you love mathematics also, you may enjoy this tip on how to use math to win your own jar of candy corn and to impress your friends. As I said, I love math, but I gu…
This is a video describing the growing solar energy use in Utah. This is a topic that greatly interests me and so I decided to produce a video about it.
Although Jacob Bernoulli (1654-1705) has been credited as the creator of "Binomial Distribution Table", Gottfried Leibniz (1646-1716) did his dissertation on the subject in 1666; Leibniz you may recall is the co-inventor of "Calculus" and beat Isaac…

777 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question