WASHINGTON -- Q: I've been using synthetic oil in my car for 14,000 miles, but the dealer mistakenly put regular oil in at the last oil change. Will this damage the engine?

A: Car expert Pat Goss says that your engine will not be harmed by the switch. But, in general, Goss says synthetic oil is better for your engine than regular oil. That's because synthetic oil has greater shear strength -- meaning it reduces friction and prevents parts in the engine from rubbing against each other. Almost all cars can use synthetic oil, and if you decide to use it, it can lengthen the life of your engine. But prepared to be pay, synthetic oil can cost twice as much as regular oil.

Q: When should I add the soap and water to my laundry, before or after I add the clothes?

A: We got the laundry lowdown from clothing expert Steve Boorstein and from Whirlpool. Both say the key to clean clothes is even distribution of the detergent. The best way to get the dirt out with a top-loading machine is to first start the water, then add the detergent, and put your clothes in last. But be careful, only add enough water to dissolve the detergent before you add the clothes or you might overflow the machine. A distribution danger is detergent poured directly on clothes, the detergent will remain concentrated on only a few garments and could leave stains. Front-loading and some top-loading washing machines have detergent dispensers to add the soap at the right time for even distribution.

Q: What is in Rice Krispies that causes them to snap, crackle and pop?

A: We contacted Kellogg's for the answer. It says starch is the secret behind the sound. Each toasted rice puff has tiny air bubbles. When you pour cold milk onto the cereal, it is unevenly absorbed into the starch structure. This causes the starch structure to swell irregularly, placing a strain on the rest of the puff. Finally, the starch structure breaks down, making the famous snap, crackle, and pop sound.

Q: I'm an avid coffee drinker, but also a diabetic. Does flavored coffee have sugar content?

A: We contacted Folgers Coffee for the answer. It says flavored coffee has no sugar content. In fact, brewing flavored coffee is the same as brewing regular coffee, because the artificial content in flavored coffee adds no calories, fats or carbohydrates. What you need to be concerned about is not whether you are drinking regular coffee or flavored coffee, but how much cream and sugar you add to your drink.

Q: Do liquid dishwashing detergents and powdered dishwasher detergents go bad?

A: We went to the Soap And Detergent Association and Procter & Gamble for this question. Both said you do not need to worry about detergents sitting on store sale shelves. Both liquid and powder detergents have long shelf lives and generally do not go bad if they have not been opened. After they are opened, however, you can usually use detergents for three to five years. That's because once detergent is exposed to air and humidity, it can clump and become less effective over time.

Q: What is the difference between a "moon roof" and a "sun roof" on an automobile?

A: The Association of International Automobile Manufactures filled us in. The main difference between the two is that the moon roof does not retract while the sun roof does. The moon roof is a stationary piece of glass with an inside cover you can slide closed but the glass does not open for air. The sun roof, on the other hand, can actually open.