The smartphone: a computer in your pocket
๐ In short
A smartphone isn't just a phone: it's a small computer with a camera, a map, a flashlight, a calculator and a library of games and books. Inside it are clever sensors that know whether you're holding it upright or sideways, where you are on the map and when your finger touches the screen.
๐คฉ Did you know?
- The first mobile phone call was made in 1973, and the phone weighed more than a kilogram!
- A modern phone has several cameras, and some can take clear pictures of the Moon.
- A phone battery can be charged and emptied hundreds of times before it wears out.
- There are more mobile phone subscriptions in the world today than there are people!
๐ Find out more
๐ A screen that feels your finger
Your body carries a tiny bit of electricity. When you touch a phone screen, the small electric current changes at exactly that spot, so the phone knows where you pressed. That's why the screen often doesn't work when you're wearing woolly gloves!
๐ Why does the picture turn?
A phone has a small sensor that feels gravity and movement. When you tilt the phone, it knows it's sideways and turns the picture so it stays straight in front of your eyes. It's the same sensor that counts your steps when you walk.
๐ก How does it know where you are?
The phone picks up signals from satellites circling the Earth. From the time each signal takes to arrive, it works out exactly where you are, so the map knows which street you're standing in.
๐ฏ Apps
Every program on a phone is called an โappโ and has an icon we tap to open it. But before downloading any app we ask our parents, because some apps collect our information or show unsuitable ads.
๐งญ Battery
A phone's battery stores electricity. A very bright screen, heavy games and searching for signal drain it fast, while โairplane modeโ saves it.
๐ Phones and privacy
A phone knows where you are, your photos and your messages, so we lock it with a code and only let an app know our location or use the camera if it really needs to.
๐ See how it works
๐ Key words
- App
- A program on a phone with an icon
- Sensor
- A part that measures movement, light or location
- Touch screen
- A screen that shows the picture and feels your finger
๐งช Try it at home
Ask one of your parents to open the compass or level app on the phone, then slowly tilt or turn the phone and watch the number change: that's the sensor at work!
๐งฉ Test yourself
1 Why does the screen often not work with woolly gloves?
2 How does the phone know where you are?