Exercises: Mobile phones, tablets and other devices

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

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

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

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 mobile phone wins.

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.

Name three things that a mobile 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.

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

A handheld console has a screen, battery, CPU and memory, like a mobile phone. Do you think it is more similar to a mobile phone or a desktop computer? Defend your answer with two arguments.

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.

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 (mobile phone, tablet or computer) and justify your choice considering the screen, keyboard and comfort.

A tablet with a keyboard case costs almost as much as a laptop computer. Analyse 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.

A mobile 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 mobile phone were empty, and then explain two reasons why in reality significantly fewer fit.

Your grandfather wants a device solely for viewing family photos, making video calls and reading the online newspaper. Choose between a mobile phone, tablet or computer, and justify your choice considering screen size, simplicity of use and where he will use it.

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

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.

A new mobile 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 (miniaturisation of components, greater efficiency) without resorting to "magic".

A "water-resistant" mobile 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.

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 mobile 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.

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 sockets. Choose between a laptop, tablet or mobile 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.

Your older brother is offered the chance to upgrade his 3-year-old phone to a new 300 € model. His current phone runs smoothly, but the battery only lasts 4 hours and the "Storage almost full" warning keeps popping up constantly. The shop assistant 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 shop assistant's argument: 1) Propose two low-cost technical solutions (one hardware and one data management) to restore its battery life and free space without replacing the device; 2) Justify the environmental impact avoided by your proposal compared to buying a new phone, mentioning the saving of raw materials and the reduction of electronic waste.

A manufacturer commissions you to define the technical specifications of the ideal computer or tablet for 1st-year ESO students with a budget limit of 250 € per unit. Resolve these three technical trade-offs, justifying your decision for each one: 1) Screen size: 8 inches (very light but small text) or 11 inches (heavier but better visual ergonomics)? 2) Casing: ultra-thin aluminium or ruggedised plastic with shockproof rubber corners? 3) Battery: 4000 mAh (lightweight device) or 7500 mAh (more weight in the backpack)? Finally, explain why buying the most expensive and powerful model in a store (for example, a 1200 € laptop) for this use would be a technical and practical mistake.

A friend states: "Handheld consoles no longer make sense because any mid-range mobile phone has a faster processor and a better screen". Refute their statement by analysing two technical problems a mobile 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 mobile accessory should incorporate if it aims to compete on equal terms with a dedicated handheld console.

Marcos has a daily routine with his mobile phone: 1) He leaves it charging all night under his pillow with an ultra-fast charger; 2) He plays graphically demanding 3D games while it is plugged into the power outlet; 3) He lets the battery drop to 0% before charging it and always waits for it to reach 100%. Explain which two physical phenomena (excessive heat and electrical voltage extremes) are chemically degrading the cells of his lithium-ion battery. Predict what will happen to the battery life in less than a year and propose a corrected routine with three clear rules of use to maximise its lifespan, explaining the technical reason for each.

The management team of a secondary school has a 25.000 € grant and proposes buying an individual tablet for each of the 80 1st-year ESO students. The headteacher states: "With this, we modernise the school and students will learn better without any added cost". As a technology advisor, write a critical report: 1) Identify two "hidden" technical costs they have not considered (software/MDM management licences, screen breakages, Wi-Fi access point saturation); 2) Propose an alternative with that same budget (such as laptop carts shared between classrooms) and justify why your proposal manages the budget better and reduces maintenance issues compared to the one-tablet-per-student model.

Observe these simplified environmental impact data: manufacturing a smartphone generates about 60 kg of CO₂ and its average lifespan is 2,5 years; manufacturing a desktop computer generates about 240 kg of CO₂, but its modular design allows upgrading parts and extending its lifespan to 10 years. 1) Calculate the annualised CO₂ footprint of each device (kg of CO₂ per year of service). 2) Based on the results, technically justify why modularity and repairability are key ecological factors in technology. 3) Interpret using data the phrase "the greenest technological device is the one you already have" in contrast to a brand's advertising campaign encouraging people to change phones every year because their new model uses 10% recycled plastic.