7th Class Science - Chapter 4: Heat

Study Notes

Heat is a form of energy that involves a shift of energy from a hotter to a cooler object.
Hot and cold can be differentiated based on the differences in their temperatures.

A thermometer is a device used to measure temperature.
Clinical thermometer is used to measure body temperature, usually in the range of 35°C to 42°C, and is widely used in hospitals and at home.
Clinical thermometer consists of a long, narrow glass tube with a bulb that contains mercury at one end.
Digital thermometers are favored nowadays because they don't contain mercury and are less harmful.
Maximum-Minimum Thermometers are used to calculate the daily minimum and maximum temperatures.
Laboratory Thermometer is used to measure temperatures of all items other than human bodies, typically in the range of 10°C to 110°C.

Heat is the transmission of energy from a hotter commodity to a cooler commodity.
Heat transfer can take place in various ways, including conduction and convection.

Conduction is a procedure of heat transfer where the heat is transmitted from the hot section to the cold section of the articles.
Examples of conductors include iron and copper.
Examples of insulators or poor conductors include wood and plastic.
Handles of most utensils are made of plastic or wood because they are insulators.

Convection is a way of heat transfer in liquids and gases, where the heat is transmitted by the shifting of the heated molecules in them.
Examples of convection include when bubbles rise to the top from the bottom of a vessel while boiling water.
Convection is the concept behind the interesting characteristics found in the coastal areas, termed the sea and land breeze.