My girlfriend recently was given an iPhone 4 for Christmas, and as a result I was interested in seeing if it was capable of doing any "cool" things. In doing a Google search for the "secrets of the iPhone 4" I came to find that there are actually MANY unknown secrets of the iPhone 4. Strangely enough, most of these secrets are not printed in the included instruction iPhone 4 manual, and from what I can tell they are not even necessarily found on Apple's own website! Some of these iPhone secrets may come as no real surprise to you, but hopefully at least a few of them will immediately make you pull out your smart phone and check them out. Many of these tricks for the iPhone 4 actually work with previous iPhone models, as well as the iPod touch; so be sure to keep that in mind as well!

1. You're iPhone can Read your E-Books and other Documents to You

This is certainly a strange thing that is implimented into the Apple iPhone 4 that most will never notice. While it does require the free iBooks application (which comes preinstalled on the iPhone 4), it is one of interesting and relatively useful tools that can make all e-books into audio books, and make going through tedious work and school documents a lot more bareable. All you have to do is turn on VoiceOver (the text-to-speech feature), open up your desired e-book or PDF document, double tap your screen, and listen to the voice read until you double tap again to make it stop. While the voice is rather robotic sounding, it is very bareable for most uses; and can in the least be pretty fun. One thing I did with this was write a piece of poetry, upload it as a PDF, then listen to the iPhone read it to me. This is a very practical application and amusing as well! This service is also excellent for someone with disabilities as well, which is why it is actually in the iBooks app to begin with.

2. Double Tap the Space Bar to Insert a Period

One thing I despise about the iPhone is the onscreen keyboard. In fact, I still use the original LG Chocolate because I preference its simplicity and hardware keyboard. However, I have also messed around with my girlfriend's iPhone; and while I have grown used to it to a certain degree, it still bothers me because of AutoCorrect and the navigation of the buttons. This little tip makes writing text messages so much easier, as we often use periods (assuming we use proper grammar anyways). It is as simple as double tapping the space bar. It will insert a period and an extra space so you can keep typing away. You can turn this setting on/off by going to Settings -> General -> Keyboard on your phone.

3. Tap and Hold to Save Images

The iPhone 4 is a great mobile phone because of all the storage capacities it has. When browsing the internet, on occasion I have found some great pictures that I would have liked to have stored on my girlfriends iPhone to show friends later (and not to mention use as a potential wallpaper). Apparently, it is possible to save images to your phone; and it is as simple as tapping the image and holding your finger on the screen. It will pop up some options like "Copy" and "Save Image." Just choose "Save Image" and the picture is yours!

4. Double Press Home to Access Music Controls

If you are listening to music, then just double press the home button to bring up the music controls. This is one of those great little iPhone 4 tips that can save time and energy navigating through your phone. I find this especially useful when out jogging and wanting to access the volume slider. Not to complicated, but it may save you a few seconds of your time.

5. Get a Scientific Calculator when You Turn Your Iphone on It's Side

This is probably one of the coolest functions of the iPhone 4 that I never realized. You no longer need to spend hundreds of dollars on a scientific calculator, as the iPhone has the functionality of one built in! I thought the iPhone calculator was only a simple mathematics instrument, until finding out that when turned on it's side it provides many more options.

Take a look at the picture of this thing below!

12 Unknown Secrets of the iPhone 4 Scientific Calculator

6. Press the Home and Sleep Buttons Together to Take a Screen Cap

This is a convenient tip that will allow you to take a picture of your screen. Simply hold the Home and Sleep buttons, and you will have deposited on your phone a picture of your screen in it's current state. Very cool to use and very simple as well! This is one of the best kept iPhone secrets.

7. Hold the Home and Sleep Buttons Together to Reboot

While these may be the same button combination as mentioned in secret #6, it is important to take note of the fact that you need to hold these buttons down for the reboot to take effect. I learned about this last week when my girlfriend's brother managed to break his phone screen causing it to freeze on him. He rebooted his iPhone and it began working without a problem again. This is a very useful Apple iPhone 4 tip that will certainly be of aid when your iPhone decides to crash and freeze on you. I just wish Apple included this information in their iPhone 4 manual.

8. Tap and Hold Any Letter for Extra Characters and Symbols

This is a very cool iPhone tip to know if you are communicating with someone who does not speak English, or speaks a different form of English. For example, if you tap and hold down the "o" button, you will be shown some additional characters that are similar in appearance including Spanish letters with cedillas. Text communication with the iPhone 4 is no longer limited to just the English alphabet and language.

Iphone 4 Secrets(76706)

9. Add Your Favorite Websites to Your Home Screen

Assuming you are using the built in Safari web browser, then this is a very simple iPhone 4 tip that may make your daily web surfing routine quicker. Open up Safari and your web page of choice, click the + button, and choose "Add to Homescreen." It is as simple as that. You can then access this website from your home screen on your iPhone. This is probably one of the most useful and simple iPhone 4 tricks.

10. Tap and Hold a Link to Copy It

Imagine you are browsing the internet when suddenly you stumble on a really interesting article, or a hilarious rage comic. Of course you want to share this with your family and friends, but often writing out the link address can be tedious and difficult. All you have to do is tap the link, and it will provide you an option to copy the address. You can then paste this into an SMS text message or an e-mail and share without all the hassle.

11. Double Tap Text or Images to Zoom In

You may have stumbled upon this one on your own by mistake, but in case you have not give this one a try right now! Open up a web page, double tap some content that seems interesting to you, and you will find that the screen zooms in so you can read or examine it's content easier. This is a very useful tool!

12. International Keyboards for International TLDs (top level domains)

Finally, the final unknown secret of the iPhone 4 (for this iPhone article list anyways) is the ability to enable international keyboards for international TLDs. You can turn this setting on by going to Setting > General > Keyboard > International Keyboards. You will then see it in a similar way as the earlier mentioned tab and hold down on the buttons and symbols, except this will be performed on the .com button. An example of this would be turning on the British keyboard symbols, which then causes the iPhone to display the British TLD Once you get a hand on using it, it becomes a very nice thing to have; especially if you frequent international websites.

I hope you have enjoyed this article documenting the 12 Unknown Secrets of the Iphone 4. While there are certainly more secrets that you can find online, these are the ones I find particularly useful when I use the iPhone. Hopefully you have been able to learn a thing or two, and if you have any secrets of your own or other related iPhone 4 tips and tricks; feel free to leave comment below. I love hearing from you!

If you're into technology be sure to check out some of my other articles including The 7 Best Free Android App Downloads Currently Available (2011) and The 7 Best eBook Readers You Can Buy.