does the money supply change?

yes

how does it change?

http://www.investopedia.com/articles/08/fight-recession.asp

You'll find everything you need to know here:

http://www.bing.com/search?q=money+supply&form=EDGNTC&qs=PF&cvid=472fbf5c08a4430cb141bdb8a2490bef&pq=money%20supply

Yes, the money supply can change over time. The money supply refers to the total amount of money circulating in an economy at a given point. It includes physical currency such as coins and banknotes, as well as demand deposits and other liquid assets held by individuals, businesses, and financial institutions.

There are several factors that can influence changes in the money supply:

1. Central Bank Actions: Central banks, like the Federal Reserve in the United States, have the authority to control the money supply. They can increase or decrease the supply in the economy by conducting open market operations, adjusting interest rates, or implementing other monetary policy measures.

2. Commercial Bank Activities: Commercial banks also play a role in changing the money supply through lending and deposit activities. When banks make loans, they create new money in the form of credit, which effectively increases the money supply. Conversely, when loans are paid off or withdrawn from deposit accounts, the money supply decreases.

3. Government Spending and Taxation: Government actions, such as spending or taxation decisions, can impact the money supply. When the government spends more than it collects in taxes, it injects money into the economy, increasing the money supply. Conversely, when the government reduces spending or increases taxes, it withdraws money from circulation, reducing the money supply.

4. Economic Factors: Economic conditions, such as changes in the level of economic activity, can also influence the money supply indirectly. For example, during periods of economic expansion, demand for money typically increases, leading to an expansion of the money supply to meet this demand.

To determine the current state of the money supply in a specific economy, one can refer to official publications or reports provided by central banks or government agencies responsible for monetary policy. These publications often highlight the key measures and indicators used to assess changes in the money supply, such as M1 (narrow money) or M2 (broad money), which capture different types of assets included in the money supply calculation.