Hot and cold tell us how warm something feels or how much heat it has. Young learners can compare hot things, like the Sun or soup, with cold things, like ice or snow. A thermometer helps us see temperature because the colored liquid moves when the temperature changes.
When it gets warmer, the thermometer goes up, and when it gets colder, it goes down.
Heat moves from warmer things to cooler things, so a warm hand can melt an ice cube. A thermometer has numbers that help us measure temperature, such as degrees Celsius or degrees Fahrenheit. The red part on many thermometers shows warmer temperatures, while blue often reminds us of cooler temperatures.
Learning hot and cold helps children choose safe clothes, understand weather, and stay away from things that are too hot to touch.
Key Facts
- Hot means a higher temperature, and cold means a lower temperature.
- Warm = thermometer goes UP.
- Cold = thermometer goes DOWN.
- Water freezes into ice at 0°C or 32°F.
- Water boils at 100°C or 212°F.
- Temperature change can be found with ΔT = final temperature - starting temperature.
Vocabulary
- Temperature
- Temperature tells how hot or cold something is.
- Thermometer
- A thermometer is a tool that measures temperature.
- Hot
- Hot means something has a high temperature and may feel warm or unsafe to touch.
- Cold
- Cold means something has a low temperature and may feel chilly.
- Heat
- Heat is energy that moves from a warmer object to a cooler object.
Common Mistakes to Avoid
- Thinking the thermometer goes down when something gets warmer is wrong because the liquid rises as temperature increases.
- Touching something to test if it is hot can be unsafe because very hot objects can burn skin.
- Calling ice hot because it is in the Sun is wrong because ice is still cold until enough heat melts it and raises its temperature.
- Mixing up weather temperature with body temperature is wrong because they are measured in the same units but describe different things.
Practice Questions
- 1 A thermometer shows 10°C in the morning and 18°C in the afternoon. Did the thermometer go up or down, and by how many degrees?
- 2 An ice cube is at 0°C. A cup of warm water is at 40°C. What is the temperature difference between them?
- 3 A child sees a red arrow going up on a thermometer and a blue arrow going down. Explain which arrow shows warming and which arrow shows cooling.