How do we measure the hottest and coldest of an object
Answers
Answer:
LEARN
VIDEO
ACTIVITY 1
ACTIVITY 2
QUIZ
GAMES
EXPLORE
Objective
This topic gives an overview of;
Heat
Measuring Temperature
Reading a Thermometer
Laboratory Thermometer
Heat
We had learnt that woollen clothes are made from animal fibres. You also know that cotton clothes are made from plant fibres. We wear woollen clothes during winters when it is cold outside. Woollen clothes keep us warm. We prefer to wear light coloured cotton clothes when it is hot. These give us a feeling of coolness. You might have wondered why particular types of clothes are suitable for a particular season.
In winter you feel cold inside the house. If you come out in the sun, you feel warm. In summer, you feel hot even inside the house. How do we know whether an object is hot or cold? How do we find out how hot or cold an object is? In this chapter we shall try to seek answers to some of these questions.
Hot and Cold
In our day-to-day life, we come across a number of objects. Some of them are hot and some of them are cold. Tea is hot and ice is cold. List some objects you use commonly in Table-1. Mark these objects as hot or cold.
Table-1
Object Cold/Cool Warm/Hot
Ice cream
Spoon in a tea cup
Fruit juice
Handle of a frying pan
We see that some objects are cold while some are hot. You also know that some objects are hotter than others while some are colder than others. How do we decide which object is hotter than the other? We often do it by touching the objects. But is our sense of touch reliable? Let us find out.
Activity - 1
Take three large mugs. Label them as A, B and C. Put cold water in mug A and hot water in mug B. Mix some cold and hot water in mug C. Now dip your left hand in mug A and the right hand in mug B. After keeping the hands in the two mugs for 2 minutes, dip the hands simultaneously in mug C . Do both the hands get the same feeling?
Then, how do we find out how hot an object really is? A reliable measure of the hotness of an object is its temperature. Temperature is measured by a device called thermometer.