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Science

Keeping the Body in Balance

Overview

Students explore how the body maintains constant internal conditions despite constant changes in the environment.

Learning Objective
Students understand homeostasis as the maintenance of a stable internal environment and can describe examples of homeostatic mechanisms.

Resources needed

  • None

Lesson stages

0 / 7 done
  1. 1 Ask: if you eat a lot of sugar, why does your blood not just stay very sweet? What happens?
  2. 2 Introduce homeostasis: the body's ability to maintain stable internal conditions despite changes in the environment.
  3. 3 Example 1 — temperature control: too hot leads to sweating and blood vessels dilating to cool down; too cold leads to shivering and blood vessels constricting to warm up.
  4. 4 Example 2 — blood glucose: glucose rises after eating, insulin released, cells absorb glucose, levels fall; glucose falls, glucagon released, liver releases glucose, levels rise.
  5. 5 Example 3 — water balance: too much water in blood leads to more urine; too little leads to concentrated urine.
  6. 6 Introduce: these are negative feedback loops — the response opposes the change.
  7. 7 Ask: what happens when homeostasis fails? (Diabetes — blood glucose not regulated; heatstroke — temperature not controlled).

Tap a step to mark it as done.

Variations

  • Test body temperature regulation: measure temperature before, during, and after mild exercise.
  • Discuss diabetes: type 1 (no insulin produced) vs type 2 (cells do not respond to insulin).
  • Connect to the nervous and endocrine systems — how do they work together in homeostasis?
More information

Teach: homeostasis, regulate, stable, feedback, insulin, glucagon, sweat, dilate, constrict. The negative feedback concept — the response opposes the change — is the key mechanistic idea.

Focus on one example of homeostasis — temperature regulation — before introducing blood glucose and water balance.

Can students explain what homeostasis means and give two examples? Can they describe one negative feedback loop, including the stimulus, the response, and why it is called negative feedback?

No resources needed. Measure temperature change during exercise using a student's own sense of warmth and sweat response.

Students sometimes confuse negative feedback with a bad or harmful process. Negative means the response reduces the change — it is the body's stabilising mechanism.

Homeostasis is one of the defining features of living things. Understanding it connects to medicine, physiology, and systems thinking in biology.

Activity details
Secondary Medium 25 minutes no prep Whole Class, Small Group Indoor & Outdoor
Topics
Homeostasis Human Body Regulation