Lesson Plan - Does Water Always Boil at 100°C? Here’s What You Should Know
The lesson plan for Does Water Always Boil at 100°C? Here’s What You Should Know helps parents and carers explore this fascinating scientific question with their children. While we often learn that water boils at 100°C, this lesson explains why that’s not always true. Using simple, clear language, the plan covers how altitude, air pressure, and added substances like salt affect the boiling point of water.
It provides a flexible structure with activities, discussion questions, creative tasks, and deeper thinking prompts. The tasks are designed to suit a wide range of ages and abilities, and the plan can be used as a one-off lesson or part of a wider science project on states of matter, weather, or kitchen chemistry.
Whether your learner prefers hands-on experiments, reading, or drawing, you’ll find something in this lesson to spark their curiosity. Parents don’t need any science background—just follow the plan and learn together! It’s ideal for Elective Home Education families who want a ready-to-use lesson that still leaves room for personalisation and creativity.
This topic is part of our Info Zone collection. You can read the full article here: Does Water Always Boil at 100°C? Here’s What You Should Know
You’ll also find a full Lesson Plan and a handy Parent Q & A Sheet ready to use.
| Does Water Always Boil at 100°C? | |
|---|---|
| Overview | This science-based home education lesson explores what really affects the boiling point of water. Learners will investigate how pressure, altitude, and other factors cause water to boil at different temperatures. Includes discussion points, critical thinking, and creative science activities suitable for learners aged 8–16. |
| Learning Objectives |
- Understand why water does not always boil at 100°C - Explore how pressure and altitude affect boiling point - Identify how boiling point is used in science and everyday life - Encourage observation, questioning, and curiosity in science |
| Estimated Time | 45–60 minutes |
| Starter Activity |
Ask your learner: “Does water *always* boil at 100°C?” Let them guess. Then discuss where they think boiling water might behave differently (e.g. on a mountain, or in space!). Optional: Show a pan of boiling water and ask what they notice. Where do the bubbles start? What causes them? |
| Read and Learn |
Read the article Does Water Always Boil at 100°C? aloud together or independently. Then reflect on the following:
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| Activities |
Comprehension Questions:
Simple Experiment:
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| Deeper Thinking |
Big Question: “Why do you think scientists need to know exactly when water boils?” Talk about space science, cooking, medicine, and safety. Encourage your learner to imagine how incorrect boiling points could affect real-life situations. |
| Creative Projects |
- Draw a cartoon showing water boiling on a mountain vs at the beach vs in a pressure cooker - Write a science comic strip explaining how altitude changes boiling point - Design an info poster for your kitchen explaining “Why Water Doesn’t Always Boil at 100°C!” |
| Review & Reflect |
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| Extensions & Homework |
- Watch a video of water boiling in space or under vacuum (check YouTube) - Research how cooking changes at the top of Mount Everest - Find out what temperature water boils at in your local area—can you measure it? |
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