📘 Teacher Guide

1. Overview

Every smartphone contains dozens of chemical elements, many of which are classed as critical raw materials: they are essential for modern technology, but their supply is at risk. This resource lets learners take a phone apart virtually, find out which elements are inside each part, what they do, where they come from, and why recycling matters.

How it works

1. Take the phone apart: the interactive 3D phone can be taken apart and put back together with the buttons or the slider, turned by dragging it sideways, and seen from the diagonal or from the back. When it is apart, name tags and dashed guide lines show how the seven layers fit together. Select a phone part by tapping it. The "Photo" button switches to an exploded-view photo instead (shown automatically on devices that cannot display 3D graphics).
2. Tap an element tile to see a photo of the element and read what it does, a fun fact and where it comes from.
3. A red corner on a tile (and a red info box) means the element is on the EU, US or UK critical-materials list.
4. Each part also shows statistics from a scientific study of old mobile phones, e.g. the value of the metals per tonne.
5. Previous / Next buttons (or swiping, or the arrow keys) move between the elements of a part.
6. Below the phone, "Parts explored" ticks off each part as it is visited (the chips can also be used to jump to a part). Once all six are done, pupils are invited to take the quiz.
7. Before a part is chosen, the welcome panel shows an Element of the day: a photo and fun fact for one element (a different one each day; the "Another one" button shuffles) with a button that opens its card. It makes a quick starter on the board. Below it, a Quick question from the quiz bank can be answered straight away, with the explanation and a link to the full quiz.
8. Each element panel shows a mini periodic table with the element's position marked. Tapping it, or the "Periodic table" button at the top of the page, opens the full periodic table with all the elements in the guide highlighted. Tapping one there shows which parts of the phone contain it.
9. The 🎮 Recycling game button (at the top, in the welcome panel and in the "What Can YOU Do?" section) opens Urban Mine: Repair Rush, described in section 2.
10. The "What Can YOU Do?" section at the bottom gives practical actions, the drawer challenge and a link to find the nearest UK drop-off point for old electricals.
11. When pupils feel ready, they take the quiz and can print a certificate with their name and score.

2. The recycling game: Urban Mine: Repair Rush

Pupils run a phone repair and recycling shop for one 2½-minute shift. Old phones ride along a conveyor belt and each one has to go to the right station before it falls into the landfill bin. The game turns the waste hierarchy into quick decisions: reuse and repair first, recycle what cannot be saved, and handle damaged batteries safely.

How to play

• Drag a phone to a station, or tap a phone and then a station. With a keyboard: the left and right arrows choose a phone, keys 1 to 4 send it to a station, F (or Space) puts out a fire and P pauses.
• A small badge on each phone shows its problem. With the tutorial switched on (the default for the first game), the first phone of each kind is labelled and an arrow shows where it should go.
• Phones that reach the red end of the belt glow, wobble and tick: last chance before the landfill!

Fires, scoring and difficulty

• Fires: a burning station stops working and everything on it is lost. Tap a fire 3 times to put it out; on Normal and Hard, a fire spreads after 10 seconds. A station with no free slot shows FULL.
• Points and money: repairs and sales earn money, which pays for spare parts. Landfill, fires and wrong choices cost points.
• ⚡ Streak: correct choices in a row double the points after 4 and triple them after 8. A mistake, a fire or a phone in landfill ends the streak.
• Events keep the shift lively: a school collection drive (a rush of phones), a heatwave (batteries catch fire sooner), a parts sale (half-price parts) and a belt that speeds up twice.
• Difficulty: 🌱 Easy (slower belt, fires do not spread), ⚙️ Normal and 🚀 Hard (faster belt, quicker fires). Each level keeps its own best score on the device. Easy suits younger pupils and first-time players.
• Daily challenge: one goal per day (for example "no fires" or "repair 8 phones") for 200 bonus points. It is the same for everyone on that day, which works well for a class competition.

End of the shift

The end screen shows the score and stars, the longest streak, the daily challenge, what happened to the phones, the metals recovered (copper, silver, gold, palladium and rare earths, using the amounts per phone from the study on the main page) and personal lessons such as "phones recycled although they could have been repaired". A link opens the card of one element from the shift on the main page, so pupils can go straight from the game back to the science.

3. Learning objectives

By the end of the activity, learners should be able to:

• name the main parts of a smartphone and some of the elements each part contains;
• link the properties of an element to its use (e.g. gold does not corrode, copper conducts electricity, neodymium makes strong magnets, lithium is very light);
• explain what makes a raw material "critical" and give examples of supply being concentrated in a few countries;
• describe environmental, social and ethical issues linked to mining (e.g. cobalt mining, conflict minerals);
• explain why old phones are a valuable "urban mine" and why reuse, repair and recycling matter;
• (extension) interpret and compare data, e.g. metal concentrations in phones versus ores.

4. Background for teachers

What is a "critical" raw material?

Governments publish lists of materials that are both important to the economy and have a supply that is at risk, for example because production is concentrated in one or a few countries, or because they are hard to substitute or recycle.

• EU: the Critical Raw Materials Act (Regulation (EU) 2024/1252) lists 34 critical raw materials, 17 of which are also "strategic" (key for green and digital technologies, defence and space).
• USA: the US Geological Survey's 2025 list contains 60 critical minerals, defined as essential to economic or national security and with a supply chain vulnerable to disruption.
• UK: the UK Critical Minerals Strategy (November 2025) lists 34 critical minerals, based on an assessment by the Critical Minerals Intelligence Centre at the British Geological Survey. Unlike the EU and US lists, it includes iron, but not copper.

The lists are reviewed every few years, so an element's status can change. For example, indium was on the EU's 2020 list but not the 2023 list, and copper and silver were added to the US list in 2025.

Key messages

• Small amounts, big value: gold, silver, platinum and palladium make up less than 1.5% of the metal in a phone, but 93% of its metal value. Copper is more than half of the metal by weight.
• Urban mining: old phones are richer in many metals than natural ores. A tonne of phone circuit boards can contain hundreds of times more gold than a tonne of gold ore.
• Concentrated supply: e.g. DR Congo mined 73% of the world's cobalt in 2025; China produced 99% of primary gallium and mined about 69% of rare earths.
• Ethics: tin, tantalum, tungsten and gold are "conflict minerals" (3TG): companies in the US and EU must check their supply chains don't fund armed groups. Some cobalt is mined by hand in dangerous conditions, sometimes by children.
• Hazardous substances: since 2006, EU rules (RoHS) have restricted lead, mercury, cadmium and some other hazardous substances in new electronics, and lead-based solder was replaced by tin-silver-copper solder.
• UK picture: UK homes are holding on to more than 880 million unused electrical items, and over 100,000 tonnes of electricals are still thrown away each year (Material Focus, 2025). In 2022 the UK produced 24.5 kg of e-waste per person, the second highest in the world after Norway. In the year to March 2026, UK waste companies recorded 1,518 fires at their sites, more than 700 caused by lithium-ion batteries.
• Recycling gap: in 2022 only about 22% of the world's e-waste was documented as properly collected and recycled.

5. Curriculum links

The resource supports topics commonly taught at ages 11–16 across the UK: Key Stage 3 and GCSE science in England, Wales and Northern Ireland, and the Curriculum for Excellence (third and fourth levels) and National 4/5 Chemistry in Scotland, as well as equivalent courses elsewhere:

6. Suggested lesson plan (50 minutes)

7. Discussion questions

8. Extension activities

Data task: how many phones for 1 g of gold?

Old mobile phones can contain up to 141 g of gold per tonne (Gómez et al., 2023). A phone weighs about 100 g. How many old phones would contain 1 g of gold?

Data task: richer than ore

Phone circuit boards contain about 28% copper. Copper ore contains about 0.5–3% copper. How many times richer in copper are circuit boards?

More ideas

• Urban Mine debrief: after playing the recycling game, ask: Why does selling or repairing a phone earn more points than recycling it? Why are swollen batteries dangerous, and why do real recycling centres take batteries out first? What happened to the phones that ended up in landfill? Which metals did you recover, and which of them are critical? What does the streak reward? Compare scores, levels and strategies across the class.
• Periodic table hunt: colour in all the elements from the resource on a blank periodic table. Where are they? What do the rare earths and the platinum-group metals have in common?
• Supply-chain research: pick one critical element and create a poster: where it is mined, how it is refined, what it is used for, and the risks.
• Drawer phones survey: how many unused phones do pupils' households have? Use the drawer challenge at the bottom of the main page to see how much copper, silver and gold they contain, then add up the whole class.
• Design challenge: design a phone that is easy to repair and recycle.

9. Using it at events, on tablets and offline

Exhibition mode

Add ?kiosk to the address, e.g. index.html?kiosk. In exhibition mode:

• after 90 seconds without anyone touching the screen, a short countdown appears and the display then resets itself for the next visitor (use ?kiosk=120 for 120 seconds, or any other number);
• links to external websites are switched off, so visitors stay in the display;
• the teacher guide link and the certificate printing are hidden;
• the recycling game works as normal; if a visitor walks away mid-game, the display resets after the idle time.

Switch the browser to full screen (F11 on Windows, Ctrl + Cmd + F on Mac). It works well on a touchscreen. Place a second device next to it running quiz.html?kiosk, so visitors can explore first and then test themselves.

Tablets and offline use

• When opened from the website, the resource can be installed as an app (e.g. "Add to Home Screen" on iPad, or the install icon in Chrome and Edge). After the first visit it also works without an internet connection.
• Alternatively, download all the files and open index.html directly. No internet is needed (only the links to external sources need one).

Good to know

• Dark mode: the pages follow the device's light/dark setting; the 🌙/☀️ button in the top corner switches manually.
• Accessibility: everything works with a keyboard (Tab, Enter, arrow keys) and screen readers, colours meet WCAG AA contrast in light and dark mode, and animations are reduced for users who have that setting on. The recycling game is fast and visual by nature; pupils who find it hard can use Easy, the tutorial, the pause button or the keyboard controls, and the phone and the quiz cover the same content.
• Languages: all the text of the interactive phone and the quiz is kept in one file per language (content/en.js), so translations can be added. A language menu appears automatically once there is more than one language.

10. Privacy & troubleshooting

Privacy

There are no accounts, cookies, adverts, analytics or tracking, and the pages load nothing from other websites. Nothing pupils do is sent anywhere. The only exception is the optional, anonymous teacher survey in section 14: it is embedded from Microsoft Forms, so that part of this page loads from Microsoft (which uses its own cookies), and it sends the answers a teacher chooses to submit. The pages only remember a few things on the device itself (in the browser's local storage): light or dark mode, 3D or photo view, the best quiz score, the game's best scores, difficulty, sound settings and the daily-challenge result. The "Parts explored" ticks last only until the browser tab is closed. The name typed for a quiz certificate is only used for printing and is not saved. To clear everything, clear the browser's data for this site.

Troubleshooting

• No 3D model? Older devices that cannot show 3D graphics automatically get the exploded-view photo, which works in the same way.
• An installed or offline copy shows an old version? Open the page while online and reload it once or twice; the new version is then stored.
• No sound in the game? Check the 🔊 and 🎵 buttons in the game and the device volume. Some tablets only play sound after the first tap.
• The game is too fast for some pupils? Choose Easy on the start screen, keep the tutorial switched on, or pause with ⏸ (or the P key).
• Printing: the worksheet button prints only the worksheet; the quiz certificate prints on one landscape A4 page.

11. About the data

• The component values, weights and metal contents come from a peer-reviewed study of 15 old mobile phones made between 2002 and 2015 (Gómez et al., 2023). Modern phones may differ; for example, most new phones now use OLED rather than LCD screens.
• Values are the gross value of the metals contained, at 2021 prices. The real value recovered is lower, because collection, dismantling and refining cost money and not everything can be recovered.
• Batteries were not analysed in that study; battery facts come from other sources.
• Production shares (e.g. "China produced 99% of primary gallium") are for 2025, from the US Geological Survey's Mineral Commodity Summaries 2026.
• Critical-list status uses the EU list (2023/2024), the US list (2025) and the UK list (2025).

A full list of sources and image credits is at the bottom of the main page.

12. The quiz & answer key

Each round of the quiz asks 10 questions chosen at random from the bank below, with the answers in a random order, so pupils can play several times. Pupils see an explanation after every answer and can review all answers at the end. The best score is remembered on each device, and pupils can print a certificate with their name and score (landscape A4).

13. Student worksheet

🖨️ Print worksheet

15. Licence & how to cite

© 2025–2026 Prof. Peter Nockemann, Queen's University Belfast (ORCID 0000-0001-9864-9702).

This resource is licensed under Creative Commons Attribution 4.0 (CC BY 4.0): you may use, share and adapt it, including in teaching materials, as long as you credit the author. The element photos are third-party images under their own licences (see credits on the main page). The exploded-view phone illustration and the interactive 3D phone model were created by the author using Google Gemini (AI generation) and adapted for this resource; the 3D graphics use three.js (MIT licence).

Suggested citation:
Nockemann, P. (2026). Hidden Treasure in Your Pocket: An Interactive Guide to Critical Elements in Smartphones. Zenodo. https://doi.org/10.5281/zenodo.23421480

Main data source: Gómez, M., Grimes, S., Qian, Y., Feng, Y. & Fowler, G. (2023). Critical and strategic metals in mobile phones. Journal of Cleaner Production 419, 138099. doi:10.1016/j.jclepro.2023.138099