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### College Physics (Urone)

Book edition 1st Edition
Author(s) Paul Peter Urone
Pages 1272 pages
ISBN 9781938168000

# When a cold alcohol thermometer is placed in a hot liquid, the column of alcohol goes down slightly before going up. Explain why?

Here the heat is transferred from the liquid to the thermometer by thermal equilibrium. During this transfer, the glass first gets in touch with the liquid and receives the heat, and expands.Whereas the volume of the alcohol remains constant for a bit, and its level drops down.

See the step by step solution

## Step 1: Conceptual Introduction

An object's kinetic energy is the energy it has as a result of its motion. It is the amount of work required to accelerate a body of a given mass from rest to a certain velocity. The body keeps its kinetic energy gained during acceleration unless its speed changes.

## Step 2: Heat transfer by thermal equilibrium

When we put a cold alcohol thermometer in a hot liquid, the heat is transferred from the liquid to the thermometer by thermal equilibrium. However, through this transfer, the thermometer glass first gets in touch with the liquid, and therefore it receives the heat and gets expanded. When the glass initially expands, the level of alcohol will decrease.

The liquid goes down when the thermometer is cooled because cooling makes the alcohol molecules of the liquid move very slowly. When they move so, their attractions can bring them closer so it goes down slightly before going up.

Therefore, at first, the glass that contains the alcohol heats up and expands.