Apple set to unveil new iPhones and iWatch

  The iPhone evolved NEW YORK (CNNMoney) Tim Cook & Co. are set to unveil the latest iDevices Tuesday.

At an event in Cupertino, Calif., Apple (AAPL, Tech30) is widely expected to unveil a pair of larger iPhones, an "iWatch" smartwatch and a mobile payments system.

The two new iPhones, likely to be dubbed "iPhone 6" are rumored to have screens that measure 4.7 inches and 5.5 inches, up from just four inches on the iPhone 5S. The larger iPhones could have scratch-resistant sapphire crystal screens along with bigger batteries to power the larger displays.

The iPhones are expected to feature Apple's new iOS 8 software, a relatively minor update from iOS 7. Among the bigger iOS 8 additions is new HealthKit application that monitors users' heart rates, sleep, weight and blood pressure among other health-related information. IOS 8 will also feature HomeKit, a new platform for people to control all the items in their homes with the iPad or iPhone.

The company may also unveil an "iWatch" smartwatch, its first wearable device. The iWatch is expected to pair with the new iPhones to display notifications, and it will likely have some health and fitness features. Oh, and it will tell time too -- we're pretty sure of that.

Google (GOOGL, Tech30) has already unveiled its smartwatch software called "Android Wear." Samsung (SSNLF), Motorola, LG and other gadget makers have already launched smartwatches, which have received mixed reviews and tepid interest from consumers.

  The Moto 360 in 60 (seconds)

Apple is also expected to launch a mobile payments platform that works with the new iPhones and iWatch. Using a technology called "near field communications," or NFC, the new iDevices will be able to interact with payment terminals in a simple tap. Apple reportedly has deals in place with the major credit card companies, including American Express (AXP), MasterCard (MA) and Visa (V).

NFC chips can also be placed in stickers. NFC stickers are a convenient way to quickly change a phone's settings -- say, silence a phone with a tap of an ! NFC sticker that's on your desk. The technology has been used in Android and Microsoft (MSFT, Tech30) Windows phones for years, but Apple has resisted putting NFC in the iPhone.