The active ingredients in something old can be gone. Advise you get some new baking powder.
The first thought is that one may have forgot to add baking powder, or not enough baking powder or the baking powder was bad. Baking powder is perishable. To test a batch, add 1 teaspoon to ½ cup hot water. If it doesn't bubble, throw it out.
new world
if you use old baking powder, the cake will not rise properly. To test the baking powder to see if its still good, put one teaspoon of baking powder in a glass, add a little water, if it foams real good, you can use it, otherwise throw it out and get new.
Depends on how out of date and how it was stored. It will probably work just fine. You might not get quite as much rise out of it, but you should get some regardless of how old it is.
an old K.C. Baking Powder can.
"William Wrigley Jr. came to Chicago in the spring of 1891. He was 29 years old, had $32 in his pocket, and possessed unlimited energy and great talent as a salesman. He started out selling soap. As an extra incentive to merchants to carry Wrigley's soap, he offered them free baking powder. When baking powder proved to be more popular than soap, he switched to the baking powder business. One day, Mr. Wrigley got the idea to offer merchants free chewing gum with each can of baking powder." - http://www.wrigley.com/wrigley/about/about_story.asp
itis about 62 years old
Your baking powder might be old. Check the date on the can or just buy some fresh.
Nine year old baking powder is definitely past its expiration date. While it might not actually be poisonous, it may have deteriorated to the point where it would no longer have effective leavening properties.
baking powder is baking soda and an acid. Today most baking powder is double acting, which means it rises once when it gets wet and again when it gets hot. The answer to the question depends on what your substituting in. Sometimes baking soda is used to adjust the pH (acid or base level) of a dish. Baking powder won't really help there. If you use the same amount of baking powder instead of baking soda in a cake it will not rise properly. I made two batches of banana bread. One using baking soda, as called for in the recipe. The other only using baking powder (without adding any cream of Tartar). They both had the same rise to them. I was very surprised. However, I think it does depend on what type of result you are trying to achieve. If you have time to experiment, then you should. There's no better teacher than experience. That's what I did.
Should work. Add a 1/2 teaspoon of Baking Soda as well for insurance. And if it's really old check for bugs. ;)
How about building a volcano out of paper mache, and then put combine vinegar and baking powder to produce an "eruption". Adding read food colour makes it more fun!