## Activity Introduction

NASA is always on the lookout for earth-like planets that we might be able to colonise in the future. 71% of the Earth’s surface is covered in water. That sounds like a lot, but how much can we actually drink? Use your mathematics skills to determine the actual amount of potable water on Earth, so NASA has a clearer idea of what to be looking for.

This is a good activity for kids to complete independently.

Ideal for: Upper Primary Ages 10 – 12

Themes:

• investigate
• brain teasers
• be creative

Time required: 30 minutes

Curriculum connections: Geography, Mathematics, Science, Numeracy

Some mess might be created as kids use water from the sink. Encourage them to be careful and to wipe up after themselves.

Kids should get eye level with the scale on the side of measuring jugs and cups to ensure they measure accurately.

Curriculum codes:

Complete lesson for classroom teachers:

Every last drop

• Calculator
• Coloured pencils or markers
• Measuring cup, 100 ml
• Measuring jug, 1 litre
• Plate
• Water from the tap
• Writing pen or pencil

[email protected] from Cool Australia

[email protected] resources are designed for parents and teachers to use with children in the home environment. They can be used as stand-alone activities or built into existing curriculum-aligned learning programs. Our [email protected] series includes two types of resources. The first are fun and challenging real-world activities for all ages, the second are self-directed lessons for upper primary and secondary students. These lessons support independent learning in remote or school settings.

Cool Australia’s curriculum team continually reviews and refines our resources to be in line with changes to the Australian Curriculum.

## Clean Water Calculations - Activity Instructions

NASA is always on the lookout for earth-like planets that we might be able to colonise in the future. 71% of the Earth’s surface is covered in water. That sounds like a lot, but how much can we actually drink? Use your mathematics skills to determine the actual amount of potable water on Earth, so NASA has a clearer idea of what to be looking for.

### PART A: Calculating

Step 1. Earth has in total 233.2 billion litres of water. Perform the following calculations to get an idea of Earth’s water stores. Remember to list your answer in litres.

 % of Earth’s total water All of Earth’s water 233,200,000,000 Litres 100% Only the fresh water 233,200,000,000 x 0.03 = 3% Frozen fresh water 233,200,000,000 x 0.024 = 2.4% Water not frozen but polluted or trapped underground 233,200,000,000 x 0.00597 = 0.597% Usable fresh water 233,200,000,000 x
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