Crop Production and Management
Microorganisms: Friend and Foe
Synthetic Fibres and Plastics
Materials: Metals and Non-metals
Coal and Petroleum
Combustion and Flame
Conservation of Plants and Animals
Cell - Structure and Functions
Reproduction in Animal
Reaching the Age of Adolescence
- Adolescence and Puberty
- Changes at Puberty
- Secondary Sexual Characters
- Role of Hormones in Initiating Reproductive Function
- Reproductive Phase of Life in Humans
- Sex of the Baby Determined
- Hormones Other than Sex Hormones
- Role of Hormones in Completing the Life History of Insects and Frogs
- Concept of Reproductive Health
Force and Pressure
Chemical Effects of Electric Current
Some Natural Phenomena
Star and Solar System
Pollution of Air and Water
One day Reeta went to a jeweller’s shop with her mother. Her mother gave an old gold jewellery to the goldsmith to polish. Next day when they brought the jewellery back, they found that there was a slight loss in its weight. Can you suggest a reason for the loss in weight?
Give reasons for the following.
Immersion rods for heating liquids are made up of metallic substances.
Match the substances given in Column A with their uses given in Column B.