Decimals and Measurement · Semester 2

Addition and Subtraction of Decimals

Performing addition and subtraction of decimals with varying numbers of decimal places.

About This Topic

Water pollution and management focus on the human impact on our water resources and the strategies used to ensure a sustainable supply. Students learn about different types of pollutants, from industrial chemicals to household waste, and their effects on aquatic life. This topic is deeply integrated with Singapore's context, highlighting our innovative water treatment processes like NEWater and desalination.

Students explore the importance of water conservation and the 'Reduce, Reuse, Recycle' mindset. By understanding the effort required to produce clean water, students develop a sense of stewardship for their environment. This topic comes alive through collaborative problem-solving where students design their own water filtration systems and debate water management policies.

Active Learning Ideas

Inquiry Circle: The DIY Water Filter

Groups are given 'polluted' water (mixed with sand, oil, and debris) and various materials (charcoal, sand, gravel, cotton). They must design and build a multi-stage filter to produce the clearest water possible.

⏱ 60 min·Small Groups

Generate mission

Gallery Walk: Singapore's Four National Taps

Students research one of the 'Four Taps' (Local Catchment, Imported Water, NEWater, Desalinated Water) and create a poster. They then move around to learn about the other three, comparing the energy and technology required for each.

⏱ 45 min·Small Groups

Generate mission

Formal Debate: The Water Conservation Challenge

The class debates the most effective way to save water in Singapore: through technology (better appliances) or through behavior change (shorter showers). Students must use scientific facts to support their arguments.

⏱ 40 min·Whole Class

Generate mission

Watch Out for These Misconceptions

Common Misconception

Filtering water makes it safe to drink immediately.

What to Teach Instead

Filtering only removes large particles; microscopic bacteria and dissolved chemicals may still remain. Discussing the difference between 'clear' and 'clean' water helps students understand the need for chemical treatment and boiling.

Common Misconception

Singapore will never run out of water because we are surrounded by the sea.

What to Teach Instead

Desalinating seawater is expensive and energy-intensive, and our land for catching rainwater is limited. Peer-led research into the costs of different water sources helps students appreciate the need for conservation despite being an island.

Frequently Asked Questions

What is NEWater?

NEWater is Singapore's brand of high-grade reclaimed water. It is produced by treating used water with advanced membrane technologies and ultra-violet disinfection, making it ultra-clean and safe to drink, though it is primarily used for industrial purposes.

How does littering in the street affect our water supply?

In Singapore, rainwater is collected through a network of drains that lead to reservoirs. Litter dropped on the street can be washed into these drains, polluting the water in our reservoirs and making it harder and more expensive to treat.

What are the main causes of water pollution?

Major causes include industrial waste, agricultural runoff (pesticides and fertilizers), oil spills, and improper disposal of household chemicals and plastics. These pollutants can harm aquatic ecosystems and contaminate drinking water sources.

How can active learning help students understand water management?

Active learning, such as the 'DIY Water Filter' challenge, puts students in the role of engineers. They experience the difficulty of removing even simple pollutants, which builds a genuine appreciation for the complexity of Singapore's water treatment plants. This hands-on struggle makes the message of 'saving every drop' much more impactful than a lecture on conservation.

Browse curriculum by country

• Americas
• US
• CA
• MX
• CL
• CO
• BR

• Europe
• UK
• IE
• FR
• DE
• ES
• IT
• NL
• PT
• SE

• Asia & Pacific
• IN
• SG
• AU