Nuclear energy
In 1938 scientists found that a heavy atom (like uranium) can split. This is nuclear fission. It gives a lot of heat and also frees more neutrons, which can split more atoms (a chain reaction).
- Uses: power plants (since the 1950s), medicine and research.
- Benefits: a lot of electricity with little carbon.
- Risks: radioactive waste, rare but serious accidents, and nuclear weapons. So countries made rules and treaties to control it.
Space exploration
The space age began with the satellite Sputnik (1957). Then came the first human in space (1961) and the Moon landing (1969). Many countries now have space programmes, including India (Chandrayaan-3 landed near the Moon's south pole in 2023).
Satellites give weather forecasts, GPS, TV and phone signals and pictures of crops and floods. Challenges: high cost and space junk. The International Space Station shows countries can cooperate.
ICT and the knowledge society
ICT (information and communication technology) means computers, phones, the internet and the software that makes, stores and sends information. Key steps: first computer networks (1969), the World Wide Web opened to the public (1991), smartphones (2007 onwards).
A knowledge society is one where knowledge and skills are the main source of wealth and progress. More people work in education, research, software, health and design.
Issues: the digital divide (some people have no internet or skills), privacy, fake news, and jobs changing. Good schools, libraries and fair access help.
Try it: benefit and risk table
Make two columns, Benefits and Risks, for each of: nuclear energy, space, ICT. Write two items each. Then pick one risk and write one rule or habit to reduce it (for example, check news before sharing).
Key formulas and definitions
- Fission = heavy atom splits into smaller parts, giving heat
- Sputnik: 1957; first human in space: 1961; Moon landing: 1969
- Web opened to the public: 1991
- ICT = tools to make, store and send information
- Knowledge society = knowledge and skills are the main source of wealth
- Digital divide = unequal access to the internet and skills
Worked examples
1. Explain a chain reaction in two lines.
A neutron splits an atom, which frees more neutrons. Those neutrons split more atoms, so the reaction keeps going.
2. Give two everyday uses of satellites.
Weather forecasts and GPS navigation. (Also TV and phone signals.)
3. Why is the digital divide a problem in a knowledge society?
People without internet or skills cannot reach information, learning or jobs, so inequality grows.
Common mistakes
- Thinking nuclear energy and nuclear weapons are the same thing: they use the same science but very different devices and rules.
- Saying the internet and the World Wide Web are identical: the web is a service on top of the internet.
- Mixing the dates: Sputnik is 1957, Moon landing 1969.
- Thinking only rich countries use satellites: weather and phone signals help everyone.