Hot, cold and temperature — Physics, 4–6 years
Learn how we compare hot and cold, and why a thermometer is useful. Physics, 4–6 years.
Idea
Temperature is a number that helps us say how hot or cold something is. A thermometer gives a more dependable answer than a finger, because it can show the same scale each time. Water in a fridge, a bath and a sunny car can have different temperatures.
Why
People needed to know whether food, bath water or weather was safe and comfortable, not merely guess from touch. They made thermometers so a change could be compared with a number. The problem it solves is sharing a clear measurement instead of saying only “a bit hot”.
Try it
Read a room thermometer in the morning: it says 18 °C. Later, sunlight warms the room and it says 24 °C. Count from 18 to 24: the temperature rose by 6 °C. The number tells us more precisely what changed than the word “warmer”.
Common mix-up
A hand can feel that one object is colder than another, so it seems like a good thermometer. But a metal chair may feel colder than a wooden chair in the same room because it takes heat from your hand faster. Feeling is useful, but a thermometer makes the comparison fair.
Where it helps
Thermometers help adults check a fever, read the weather and make sure a bath is not too hot. Ovens and fridges also use temperature measurements to cook or store food properly. These numbers help people choose a safe action.
Keep exploring
Other languages
Loading MyLeoNes™…