1. Why does the temperature of a substance remain constant during its melting point or boiling point?
ScienceClass 9CBSEAnswered 27 Mar 2026
Answer
The temperature of a substance remains constant during melting and boiling points till the completion of melting and boiling because of latent heat of fusion used by the substances. Latent heat of fusion helps to overcome the force of attraction between particles of solid to change into liquid when they melt. Hence temperature remains constant.
I the same way during formation of vapours latent heat helps solid substance to convert into gaseous state. Hence temperature of a substance remain constant at boiling point.
Suggested Q&A
Science · Class 9- ScienceClass 9Comment on the following statements: (a) Evaporation produces cooling. (b) Rate of evaporation of an aqueous solution decreases with increase in humidity. Sponge though compressible is a solid.
- ScienceClass 9You want to wear your favourite shirt to a party, but the problem is that it is still wet after a wash. What steps would you take to dry it faster?
- ScienceClass 9It is a hot summer day, Priyanshi and Ali are wearing cotton and nylon clothes respectively. Who do you think would be more comfortable and why?
- ScienceClass 9Alka was making tea in a kettle. Suddenly she felt intense heat from the puff of steam gushing out of the spout of the kettle. She wondered whether the temperature of the steam was higher than that of the water boiling in the kettle. Comment
- ScienceClass 9Water as ice has a cooling effect, whereas water as steam may cause severe burns. Explain these observations.
- ScienceClass 9Classify the following into osmosis/diffusion Swelling up of a raisin on keeping in Spreading of virus on Earthworm dying on coming in contact with common Shrinking of grapes kept in thick sugar Preserving pickles in Spreading of smell of cake being baked throughout the Aquatic animals using oxygen dissolved in water during respiration