The phone in your pocket
Think about your phone. Somebody took metals out of the ground to make it. Factories used a lot of power to build it. Soon you will want a new one.
What happens to the old one?
New technology gives us a lot. It also costs us something. Today you look at four more technologies, and you learn how to judge them.
Key words
| Word | What it means | Example |
|---|---|---|
| Open source | Software whose code anyone can read, use and change, under a licence. | Linux, Python |
| Licence | The rules that say what you may do with software or work. | You may use it, but you must share changes |
| Blockchain | A shared record, kept by many computers, that is very hard to change in secret. | A record of who owns a digital coin |
| Rare metal | A metal that is limited and hard to get, used in electronics. | Lithium in batteries |
| E-waste | Old electrical and electronic things that are thrown away. | A broken phone |
| Sensor | A part that measures something, such as light or movement. | A camera on a car |
| Autonomous | Able to act without a person controlling every move. | A self-driving car |
| Robot | A machine that does physical work, often on its own. | An arm that builds a car |
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Quick check: the phone
Have a go
Quick check: the phone
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Open source software
Open source software has code that anyone can read, use and change. The rules are in a licence.
Python, Linux and Firefox are open source. Many apps and websites are built on open source parts.
Closed software is different. The company keeps the code secret and you pay to use it.
Open source: for and against
| For | Against |
|---|---|
| Free or cheap to start using | There may be no company to call for help |
| Many people check the code and find faults | A fault in a popular part affects many systems |
| You can change it to fit your needs | You must read and follow the licence |
| No single company controls it | Some projects stop when volunteers leave |
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Blockchain
A blockchain is a list of records. Each record is a block. The blocks are joined in a chain.
Many computers keep a copy of the whole chain. If one person changes a block in secret, the other copies do not match, so everybody sees it.
It is used for digital coins, for tracking food from farm to shop, and for proof of certificates.
Blockchain: for and against
| For | Against |
|---|---|
| Records are very hard to change in secret | Some kinds use a lot of electricity |
| Many computers share the record, so there is no single owner | It can be slow and complex |
| Good for proof: who owned what, and when | A mistake in a record is hard to correct |
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