Hand soaps and foaming hand soaps have become very popular on the market as a cleaner alternative to bar soap. The pump action in each bottle dispenses a premeasured amount of soap, but foaming hand soap differs from hand soap in several ways.
Hand soap bottles usually have a pump at the top and do not drip. Foaming hand soap bottles are similar, but the pump at the top not only dispenses the liquid soap, it aerates it as well, causing the soap to foam as it is dispensed.
Hand soap is usually comprised mainly of soap. Foaming hand soap has a much higher ratio of water to soap so that it does not clog the pump. This ratio is also key to the foaming action, which occurs when the pump aerates the watered down soap, causing foamy bubbles to form.
Hand soap is usually much thicker in consistency than foaming hand soap. Foaming hand soap has a much higher water content and therefore will be much more liquidy in the bottle. When it is dispensed, the hand soap will require water and rubbing to form a lather. The foaming hand soap will already be lathering as it comes out of the bottle thanks to the special foaming hand soap dispenser.