Download CBSE Class 8 Science Syllabus for 2022-2022






FAQs on CBSE Class 8 Science Syllabus for 2023-24 Examination - Free PDF Download
1. What is synthetic fibre? What are the examples of synthetic fibre?
Synthetic fibres are made from materials like petroleum to form a different compound. These fibres are ideally the product of chemical extraction to create a sturdy and vibrant fabric. Methods, like melting of plastics or heating the chemical compounds and then pulling strings via tweezers, are traditional manufacturing techniques. Next, the molecules are parallelly aligned to create a crystallised residue conjoined together into a lustrous fibre. Another method called heat-setting is applied to create a colourful fibre dipped in dye.
Some of the common types of synthetic fibres are nylon, polyester and acrylic.
2. What do you mean by Deforestation?
Deforestation is a harmful practice by humans who remove trees and plants from the selected area. This includes grazing and clearing agricultural lands to construct a building and using the woods for commercial purposes. Deforestation ideally affects the habitat and food source of animals.
Not only human-made causes, but this phenomenon is also a cause of severe fire or drought-like situation. Deforestation can again reduce the water level and lead to soil pollution. This issue can be tackled by planting many trees or afforestation and practising sustainable living habits. Students must be taught ways of effective conservation and encouraged to spread this knowledge among friends.
3. What are the characteristics of a sperm?
Sperms are also termed as the male gametes that combine with female eggs to produce offspring. Some of the primary characteristics of sperm are- Testes produce millions of sperm in a male body. Each sperm has a head, a middle piece and a tail. These sperms compete with others to reach the female egg. The middle part of a sperm contains mitochondria that offer energy during the movement and flow. Sperms are stored in testes as the body temperature of a human body can cause their destruction.
4. How is human life turning unsustainable as mentioned in CBSE Class 8 NCERT?
Human life has been dependent on nature for economic prosperity. Humans started exploring it to meet many of their needs. As the population grows, so do the needs. The demands of humans turned unprecedented. They started exploiting nature without a thought for the future. They built factories that emitted harmful gasses into the air. Humans have cleared forests to extend agricultural lands. All of this led to global warming and pollution. On the other hand, most of the natural resources were depleted due to excess stress on them. They have ended us up on an unsustainable path. Now, humans are turning towards a sustainable way by adopting non - renewable energy practices.
5. What are metals and non - metals discussed in CBSE Class 8 NCERT?
Things around us are generally classified into metals and non - metals. So it is important to know how to differentiate them and what they actually are. Metals are elements that readily lose electrons to form cations. For example, copper, aluminum and gold. There are around 90 elements that are metals in the periodic table. On the other hand, non - metals are those elements that do not exhibit the properties of metals. For example, carbon, boron etc., Metals are hard and tensile in strength. Generally, metals are solids at room temperature except for mercury which is liquid at room temperature.