Hint: A better taste of the soup is obtained if the soup is creamy and spreads evenly into the whole surface of the tongue. If the soup spreads all over the tongue, more taste buds will be able to sense the taste of the soup. Different regions of the tongue have different kinds of taste buds that can completely sense all the essences and tastes in the soup.
Complete step by step answer:
When a liquid is heated, its cohesion and adhesion values decrease thus the attractive forces acting on it decreases. This can be used to say that the surface tension of a liquid decreases with the increase of temperature. Thus, the property of liquid to take a shape of least possible surface area is relaxed with increase of temperature and it will occupy a larger surface area.
Thus, when a soup is heated, its surface tension value will decrease and it will tend to occupy a larger area. Thus, it will spread on our tongue properly and evenly. This proper spread of soup on our tongue results in a better taste of the hot soup than the cold soup.
So, the assertion that hot soup tastes better than the cold soup is correct and reason is also correct which is also the correct explanation of the assertion.
Note: Students might think that a hot soup tastes better due to the intense aroma that the hot soup gives out that a cold one cannot. Though this is partly true since the human brain relates a good aroma to good taste, however, the main reason why a hot soup tastes better is because the surface tension is lowered and the soup spreads evenly over the whole surface of the tongue.
