ideas to make models in economics for ninth grade students?

Question

models which either show about different economic backgrounds in india,etc.

Answer 1

I would suggest something on the nature and importance of trade. The fact that nominally sensible adults as well as politicians are talking about "energy independence" and similar nonsense shows that many do not understand the importance of trade.

There are a number of possible models, but the most interesting is the principle of comparative advantage, which says that even if you are better than I am at making bread and making better, maybe you should concentrate on making bread while letting me make your butter:

http://en.wikipedia.org/wiki/Comparative_advantage

Another possibility is to explore the implications of compound interest. Borrowing from the future, whether with credit cards, car loans, or mortgages, is a fundamental element of economic activity we all participate in. Understanding compound interest and the idea of "the cost of money" is therefor important to all of us.

http://en.wikipedia.org/wiki/Compound_interest
http://www.bankrate.com/brm/mortgage-calculator.asp
http://www.finaid.org/calculators/compoundinterest.phtml

Answer 2

Give me more background on your project, I have some ideas. For example, if you go to UN's database you can download a ton of information on countries.

Have you studied regression analysis?