Back to homeAP® Computer Science Principles · AP Computer Science Principles · Change subject
Start for free
AP CSP · AP® Computer Science Principles
Digital devices · Beyond the computer

Cell phones, tablets and other devices

Your cell phone fits in your pocket and a desktop computer takes up half a desk, but inside they are relatives: both have a CPU, memory and storage. An operating system (OS) such as iOS, Android, Windows or macOS manages that hardware and the apps on every one of them. Here you will find out what they have in common, how they differ and how to choose the right device for each task.

Relatives of different sizes

On the outside they are very different. On the inside, they all solve the same problem: calculating, saving and displaying data.

Desktop computer, tablet, cell phone and smartwatch drawn at approximate scale: they are very different on the outside, but they all have a CPU, RAM and storage. Computer large screen Tablet Phone Smart watch all have inside CPU · memory · storage

What changes between them is their size, whether they have a battery and what task they are designed for.

Practice★☆☆Not started
Name three components that your cell phone shares with a computer and explain in one sentence what each one does inside the phone.

Name three components that your cell phone shares with a computer and explain in one sentence what each one does inside the phone.

Solve
Practice★☆☆Not started
The figure compares a computer and a cell phone: the central capsule shows the components they share, but one is missing, as shown in the diagram. Which shared component…

The figure compares a computer and a cell phone: the central capsule shows the components they share, but one is missing, as shown in the diagram.

Computer large screen · keyboard Cell phone battery · touch screen · pocket BOTH HAVE CPU RAM ?

Which shared component is missing from the capsule and what is it used for? Look also at the differences shown below each device and explain a task in which the computer wins and another in which the cell phone wins.

Solve
Practice★☆☆Not started
Name the device corresponding to each description: (a) fits in a pocket and is used to make calls; (b) has a large screen designed for reading for hours without eye…

Name the device corresponding to each description: (a) fits in a pocket and is used to make calls; (b) has a large screen designed for reading for hours without eye strain; (c) connects to the TV and is operated with a controller for gaming; (d) is worn on the wrist and tracks your steps.

Solve

The right device for each task

Comparison between cell phone, tablet and laptop ordered from smallest to largest screen size, with the most suitable tasks for each one. Phone Tablet Computer messages, quick photos reading, watching videos, drawing essays, editing small screen large screen
Practice★☆☆Not started
Think about these devices: laptop computer, tablet, cell phone, game console and e-reader. Choose three of them and explain one task for which each is better than the…

Think about these devices: laptop computer, tablet, cell phone, game console and e-reader. Choose three of them and explain one task for which each is better than the others.

Solve
Practice★☆☆Not started
Name three things that a cell phone and a tablet have in common (touch screen, battery, apps...) and one important difference between them, explaining how that…

Name three things that a cell phone and a tablet have in common (touch screen, battery, apps...) and one important difference between them, explaining how that difference is noticed when using them.

Solve
Practice★★☆Not started
You have to do three tasks: write a long essay, edit a photo for a presentation, and inform your group of a change of plans. State which device you would use in each…

You have to do three tasks: write a long essay, edit a photo for a presentation, and inform your group of a change of plans. State which device you would use in each case (cell phone, tablet, or computer) and justify your choice considering the screen, keyboard, and comfort.

Solve
Practice★★☆Not started
A tablet with a keyboard case costs almost as much as a laptop computer. Analyze two advantages and two disadvantages of studying using only the tablet (notes,…

A tablet with a keyboard case costs almost as much as a laptop computer. Analyze two advantages and two disadvantages of studying using only the tablet (notes, assignments, online exam) and conclude whether you think it could replace the laptop in your case.

Solve
Practice★★☆Not started
Compare writing a four-page essay on a cell phone using an on-screen keyboard with writing it on a laptop: analyze the speed, comfort and errors you would make in each…

Compare writing a four-page essay on a cell phone using an on-screen keyboard with writing it on a laptop: analyze the speed, comfort and errors you would make in each case, and describe a situation in which the cell phone would indeed be a good option for writing.

Solve
Practice★★★Not started
A photographer travels for two weeks doing reports: she needs to review and select photos every night, write articles and send them, and does not always have access to…

A photographer travels for two weeks doing reports: she needs to review and select photos every night, write articles and send them, and does not always have access to power outlets. Choose between a laptop, tablet or cell phone as the main device for the trip, justify your choice (screen, battery life, weight, storage) and explain which accessories you would recommend to her.

Solve

How much fits in your pocket

Bar showing a cell phone's total storage divided into three parts: system and apps, videos and free space, with the warning that the advertised free space is not all the space available. system + apps videos free total storage the "free" space on the label is never all the space available
Practice★★☆Not started
A cell phone has $64\ \text{GB}$ of storage and each photo takes up on average $12\ \text{MB}$. Knowing that $1\ \text{GB}$ is equivalent to $1\,000\ \text{MB}$,…

A cell phone has $64\ \text{GB}$ of storage and each photo takes up on average $12\ \text{MB}$. Knowing that $1\ \text{GB}$ is equivalent to $1\,000\ \text{MB}$, calculate using the division $\frac{64\,000\ \text{MB}}{12\ \text{MB}}$ how many photos would fit if the cell phone were empty, and then explain two reasons why in reality significantly fewer fit.

Solve
Practice★★☆Not started
An e-reader has $8\ \text{GB}$ of storage and each book takes up on average $2\ \text{MB}$. Calculate using the division $\frac{8\,000\ \text{MB}}{2\ \text{MB}}$ how…

An e-reader has $8\ \text{GB}$ of storage and each book takes up on average $2\ \text{MB}$. Calculate using the division $\frac{8\,000\ \text{MB}}{2\ \text{MB}}$ how many books fit and estimate how many years you could read at a rate of one book a day (a year has $365$ days). Comment on whether it makes sense to worry about space on this device.

Solve

Battery and durability

Battery at 70% charge and three habits that reduce consumption and make the charge last longer: lowering the brightness, closing apps and turning off Wi-Fi that is not being used. battery at 70% makes the charge last lower brightness close apps turn off Wi-Fi
Practice★☆☆Not started
Explain what a device battery is and why desktop computers do not need a battery to operate, whereas cell phones, tablets and laptops do.

Explain what a device battery is and why desktop computers do not need a battery to operate, whereas cell phones, tablets and laptops do.

Solve
Practice★☆☆Not started
An e-reader lasts for weeks without charging and a tablet only lasts a few hours. Relate this difference to their screens (E Ink vs. bright touch screen) and to the…

An e-reader lasts for weeks without charging and a tablet only lasts a few hours. Relate this difference to their screens (E Ink vs. bright touch screen) and to the amount of calculations each device performs.

Solve
Practice★★☆Not started
A "water-resistant" cell phone and a normal one fall into a puddle. Explain what it means for a device to be sealed against water and dust, and name two other everyday…

A "water-resistant" cell phone and a normal one fall into a puddle. Explain what it means for a device to be sealed against water and dust, and name two other everyday devices gaining this protection (watches, earphones...), explaining why they need it.

Solve
Practice★★★Not started
You are on a mountain hike, you only have 15% battery left, there is almost no coverage on any stretch, and you need the phone to stay on for 4 hours to let people know…

You are on a mountain hike, you only have 15% battery left, there is almost no coverage on any stretch, and you need the phone to stay on for 4 hours to let people know when you arrive. A friend tells you: "Set the screen to maximum brightness to see well in the sun, leave GPS and cellular data searching for a signal in case a message comes through, and close and reopen the maps app every five minutes so it doesn't consume battery". Critically analyze why these three pieces of advice drain the battery much faster, linking it to the processor, the screen, and the modem. Then, design the optimal technical protocol of 3 settings that you should activate immediately so that the device survives until the end.

Solve
Practice★★★Not started
A friend states: "Handheld consoles no longer make sense because any mid-range cell phone has a faster processor and a better screen". Refute their statement by…

A friend states: "Handheld consoles no longer make sense because any mid-range cell phone has a faster processor and a better screen". Refute their statement by analyzing two technical problems a cell phone suffers from when running demanding games for two consecutive hours (thermal throttling and accelerated battery drain) compared to the active cooling system of a console. Then, design what three hardware features (physical or thermal) a cell phone accessory should incorporate if it aims to compete on equal terms with a dedicated handheld console.

Solve

Smaller but better: miniaturization and aging

A large 2016 chip and a much smaller 2026 chip. Both have the same number of transistor blocks, but in the new one they are tinier and use less energy to do the same work. 2016 chip 2026 chip new generation transistors more energy less energy same work, less space and less energy

Batteries, on the other hand, age: every full charge and discharge wears them down a little, so a one-year-old cell phone lasts less than when it was new.

Practice★★☆Not started
A new cell phone is smaller and lighter than one from five years ago, yet it has a better camera, more memory and a larger battery. Explain how it is possible for…

A new cell phone is smaller and lighter than one from five years ago, yet it has a better camera, more memory and a larger battery. Explain how it is possible for devices to improve while becoming smaller (miniaturization of components, greater efficiency) without resorting to "magic".

Solve

The greenest device is the one you already have

Making a cell phone requires mining, a factory and transport, with a large impact; using it uses only a little energy each day. The manufacturing impact is spread over more years if the device lasts 6 years than if it lasts 2. make use lots of energy and materials a little each day The impact of making it is spread over the years of use 2 years 6 years manufacturing impact per year of use
Practice★★★Not started
Your older brother is offered the chance to upgrade his 3-year-old phone to a new 300 dollars model. His current phone runs smoothly, but the battery only lasts 4 hours…

Your older brother is offered the chance to upgrade his 3-year-old phone to a new 300 dollars model. His current phone runs smoothly, but the battery only lasts 4 hours and the "Storage almost full" warning keeps popping up constantly. The store employee tells him: "That phone is already junk; it's more cost-effective to buy a new one than to try to fix it". Technically refute the store employee's argument: 1) Propose two low-cost technical solutions (one hardware and one data management) to restore its battery life and free up space without replacing the device; 2) Justify the environmental impact avoided by your proposal compared to buying a new phone, mentioning the savings of raw materials and the reduction of electronic waste.

Solve

Summary

See all the exercises in this section