Just like matter changes from one form to another, there are different ways money changes from one person to another person or company, especially when it comes to paying for things. Let's look at a few different ways people can spend money and why you might choose one way over the others for different kinds of spending.

1. Cash
When you pay cash to buy things, you know you already have the money to make your purchases. You won't owe anything after you pay in full with cash. But cash purchases can be harder to keep track of. To stay on top of where your money goes, it's a good idea to keep your cash receipts in a safe place or write down the important information from those receipts.

2. Check
Many people have some of their money in a checking account. This becomes important as you get older and need a safe place to keep track of your money and pay regular expenses, like electric bills or phone bills. Checks are one way to move money out of your checking account. You can think of a check as a promise to pay. Some companies may ask you to pay by check so that they have a good record of that payment.

You've probably seen a parent or other adult write a check, or maybe you've even been sent one. But do you know how to read or write out a check? To challenge your check writing skills, use your mouse to roll over this check to see if you know what the numbered parts mean.

3. Check Card
A check card is like a plastic version of a check that you can use to pay for things or to take cash out of your checking account. If you use a check card to make purchases, that money is automatically taken out of your account. You have to have enough money for the payment, or your card will be declined (not accepted). Be careful; it's easy to use your card, so purchases can add up quickly. Just like with other methods of spending, it's important to keep good records of check card purchases.

You can also use your check card at ATMs (Automated Teller Machines) to "access" your checking account. This means you can get cash out or deposit money into your account by using this card without going into the bank. You can find ATMs outside of banks, in shopping centers or even at gas stations. ATMs are owned by different banks, but you can use any of these machines to access your account. Just remember that if the machine doesn't belong to your bank, you might be charged a fee to use it.

4. Credit Card
When you use a credit card, it lets you put off paying for your purchase until sometime in the future. Banks or other companies that issue credit cards let you borrow their money when you use their cards. If you don't pay all of what you owe on time that month, you'll have to pay interest on the amount you still owe (or balance). Owing something means you are in debt.

As you get older, you may want to use a credit card for emergencies that you don't have money to pay for right away. But credit cards can be too easy to use. And if you do not manage your money wisely, it can take you a long time to pay off. This becomes very expensive as interest charges keep adding up.