Have you ever pulled your hand away from something hot without even thinking? That is your body reacting to a stimulus. A stimulus is anything that makes your body act, and the action your body does is called a response.
Your five senses help you react
Your sense organs notice stimuli around you. Each sense organ is good at noticing a different kind of change:
| Eyes | light and colour |
| Ears | sound |
| Nose | smell |
| Tongue | taste |
| Skin | touch, heat and pain |
Key idea
Stimulus → a sense organ notices it → response (your body acts). The stimulus always comes first, and the response comes after.
Example
A bright light shines in your eyes (stimulus). You blink and turn your head away (response). This happens very quickly to protect you.
Remember
- Different sense organs notice different stimuli.
- Reacting to danger fast, like moving away from fire, helps keep you safe.