2. HOW THEY WORK A cell phone is basically like a A cell phone uses one frequency to talk and another to listen When you make call, When you talk the cell phone would send analog signals to the tower, or with digital it would send waves. Then the tower would send a signal to the other cell phone that they have a call

3. HOW THEY WORK Then the towers will then open up a channel connect both cell phones When you driving your cell phone automatically switches over to another cell tower so you don’t loose your signal The signal that the cell phones and towers have are called frequencies. The phone and the tower send frequency signals each other when you are calling someone, basically every time you talk and listen

4. Samartphones Smartphone took the cell phone other level You could now do multiple things at the same time You could browse the internet Check your email Play games Social Networking

5. 1G vs. 2G 1G In each cell has 56 voice channels, so only 56 people can be talking at the same time 2G This was the step form analog to digital Now the number of channels increases for 56 to 168

6. 3G vs. 4G 3G It was faster to transmit data than 2G Also you could stream videos, audio, and much more. 4G Its basically a step from 3G, faster.

7. Future of the phone IPhone 6 3D 5.5 inch screen Face recognition Security 10 MEGAPIXEL Camera rear and 8 in front Full 1080p HD Recording AND 3D Video Recording / Display Samsung Flexible phone

8. Sources http://electronics.howstuffworks.com/cell-phone2.htm

9. Global Positioning System How They Work

10. GPS BACKGROUND The GPS was built by the US military in 1995. There are currently 31 satellites angled at 55 degrees to the equator. The satellites orbit 20,000km (12,430miles) from the earth and make two orbits per day. The orbits are designed to have six satellites in view from most places on earth.

11. HOW IT WORKS A GPS receiver gets a signal from a GPS satellite The satellite transfers the exact time the signals are sent By subtracting the time the signal was transferred from the time it was received, the GPS determines how far it is from the satellite.

12. HOW IT WORKS (CONTINUED) A complication with the GPS is calculating the time it took for the signal to be received. GPS satellites have atomic clocks keeping precise time, but it isn’t feasible to give a receiver an atomic clock. If it receives a fourth satellite, it solves the equation it determines the exact time.

13. TRILATERATION A simple mathematical principal similar to triangulation and using a series of circles for two-dimensional problem solving, and spheres for three-dimensional problem solving.

14. WORKCITED http://www.maptoaster.com/maptoaster-topo- nz/articles/how-gps-works/how-gps-works.html