Exploring the Investigative World of Science — Class 8 Science
Curiosity · Chapter 1
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6- Mathematics
- Science
- + 3 more
- Space weighted by chapter size
- Charts from the book's own data
- Traps corrected
2- Mathematics
- Space weighted by chapter size
- Charts from the book's own data
- Traps corrected
- Space weighted by chapter size
- Charts from the book's own data
- Traps corrected
- Space weighted by chapter size
- Charts from the book's own data
- Traps corrected
Chapter summary
Key ideas & terms
- Scientific question
- A focused, testable question that can be explored through observation or simple experiments rather than guessed at.
- Variable to control
- A factor an investigator can change or keep fixed in an experiment, such as dough thickness or oil temperature.
- Observation
- Information gathered using the senses or instruments, which may be a yes/no answer or a measured number.
- Systematic investigation
- A planned approach in which one factor is changed at a time while others are kept constant, with careful record-keeping.
- Fair test
- An experiment in which only the factor being studied is varied so its effect can be judged honestly.
- Curiosity
- The drive to wonder about and question the world, treated here as the starting point of all scientific inquiry.
Extra questions & answers
What is the main new skill the chapter says Grade 8 students should learn?
Not just to learn new facts, but to learn how to find new facts through focused questions, simple experiments, and careful observation.
Why is the puffing of a puri used as an example?
It shows that science is everywhere, even in the kitchen, and that an everyday event can be investigated like any scientific puzzle.
In the puri experiment, name two things that can be changed or controlled.
Examples include the thickness or size of the rolled dough, the type of flour, the oil temperature, and the way the dough is dropped into the oil.
In the puri experiment, name two things that can be observed or measured.
Whether the puri puffs up (yes/no) and the time in seconds it takes to puff up.
Why should we change only one thing at a time in an experiment?
So that any difference in the result can be linked to that single change and not confused with other factors.
Why is keeping notes important during an experiment?
Recording everything sensed, such as splatter, smell, or smoke, helps make sense of results and raises new questions for further study.
What do the root and the kite symbols on the page numbers represent?
The root stands for a solid foundation of careful observation and heritage; the kite stands for curiosity and creative ideas taking flight.
Does science require a fancy laboratory? Explain.
No. Even a home kitchen is a good place to observe, ask questions, and do simple experiments.
What does it mean that the puffing of a puri is "not fully understood" by scientists?
Even simple everyday events can still hold open questions, showing that science is always evolving and never finished.
What is the value of asking new questions after an experiment?
New questions, such as whether fresh or stored dough puffs better, drive the next round of investigation and deepen understanding.
Probe and ponder
Why is one side of a puri thinner than the other?
A puri puffs because water in the dough turns into steam in the hot oil and the steam gets trapped inside the two layers of the dough. The puri is rolled flat, so it has a top and a bottom surface. When it is placed in hot oil, the outer layer that touches the oil first gets cooked and becomes a little stiffer, while the inner steam pushes outward. The layers do not stretch equally — the upper layer is freer to stretch and becomes thinner like a balloon, while the lower layer stays slightly thicker. The way we roll the dough and the way we slide it into the oil also makes the stretching uneven, so one side ends up thinner than the other. Even scientists say this everyday observation is not yet completely understood and is a good example of systematic investigation.
Are there more grains of sand on all the beaches and deserts of the world, or more stars in our galaxy?
Scientists estimate by counting samples and then multiplying. The number of grains of sand on all beaches and deserts of Earth is about
Right from Grade 6, we’ve observed the incredible diversity of plants and animals around us. From the different shapes of leaves to the many kinds of insects—why has nature created such a vast variety?
Nature has not created variety all at once, it has developed over millions of years through evolution. Living things show small differences due to variation in their genes. Some variations help an organism to survive better in its particular place — for example, a leaf shape that captures more sunlight, or an insect colour that hides it from predators. This is called adaptation and natural selection. Those better-adapted organisms survive and reproduce more. Over long periods, different environments like deserts, forests, oceans and mountains select for different traits, leading to many species. This variety also helps ecosystems stay balanced, as different plants and animals depend on each other for food, shelter and pollination.
Is there such a question that makes you curious about the world? Write it here!
This is an open prompt for you to write your own curiosity question. Any genuine wonder question is correct. For example: Why does dough rise when we add yeast and keep it warm? Or, Why does the Moon look a little different every night after purnima? A good scientific question starts with observing carefully, then asking How or Why, and thinking how you could test it by changing one thing at a time and measuring what happens.