Class 8 Science Chapter 1 – Exploring the Investigative World of Science from NCERT Curiosity with easy Notes and complete Book Solutions. Get simple explanations, important concepts, questions and answers, and revision material for effective learning, practice and exam preparation.
Exploring the Investigative World of Science
Curiosity — Textbook of Science for Grade 8
Easy Introduction
Science begins with curiosity. We see something, wonder about it, ask questions and then try to find answers.
In Grade 8, we move one step further. We learn how to investigate questions scientifically by observing, measuring, experimenting and recording what we find.
Even simple things around us, such as a puri puffing in hot oil, can become interesting scientific investigations.
Short Easy Notes and Concepts
1. Science Begins with Curiosity
Science begins when we wonder about things and ask questions such as “Why?” and “How?”
2. Investigation in Science
Investigation means asking a focused question and trying to find its answer through careful observation and experiments.
3. Observation
Observation means carefully noticing what happens using our senses or suitable measuring tools.
4. Experiment
An experiment is a planned activity used to test an idea or answer a scientific question.
5. Variables
A variable is something that can be changed in an experiment. We should change only one factor at a time when possible.
6. Recording Results
Scientists record observations and measurements so that they can compare results and understand what happened.
Root and Kite Symbols
Root
The root symbolises a strong foundation of knowledge and our connection with our environment, traditions and heritage.
Kite
The kite reminds us that curiosity should take flight and help us explore the unknown.
Our Journey in Grade 8 Science
| Area | What We Explore |
|---|---|
| Microorganisms | Tiny organisms that can be helpful or harmful. |
| Health | Nutritious food, exercise, medicines and vaccines help us stay healthy and fight infections. |
| Electricity | Heating and magnetic effects of electric current are useful in many devices. |
| Force | Forces can make objects speed up, slow down or change direction. |
| Pressure | Pressure is related to how force is distributed over an area. |
| Weather | Differences in air pressure can cause winds, storms and cyclones. |
| Particles and Materials | Matter is made of tiny particles. Materials can be classified as elements, compounds and mixtures. |
| Solutions | A solution forms when a substance such as sugar dissolves in another substance such as water. |
| Light | Light can reflect from surfaces and bend when passing through lenses or different materials. |
| Moon and Calendars | Careful observation of the Moon’s phases helped humans develop calendars. |
| Ecosystems | Living organisms depend on air, water, sunlight and other organisms. |
| Earth and Climate | Earth’s suitable conditions support life, while human activities can affect its climate. |
Systematic Investigation
A scientific investigation should be planned carefully. We should ask a focused question, decide what to change, observe the results and record what we find.
- Ask a question: Decide what you want to find out.
- Choose what to change: Select the factor you want to test.
- Keep other conditions the same: This makes the comparison fair.
- Observe or measure: Record what happens.
- Record the results: Write down observations carefully.
- Compare the results: Look for patterns or differences.
- Ask new questions: One investigation can lead to more questions.
The Puri Investigation
Why does a puri puff up?
A puri or batura can puff up when placed in hot oil. This simple everyday event can be investigated scientifically.
We can change things such as the thickness and size of the rolled dough, type of flour, temperature of the oil and the way the dough is put into the oil.
We can observe whether the puri puffs up and measure the time it takes to puff up.
Book Questions with Short Answers
Why is one side of a puri thinner than the other?
Answer: It may be due to uneven thickness of the rolled dough or the way the dough is placed in the hot oil. The chapter encourages us to investigate this question scientifically.
Are there more grains of sand on all the beaches and deserts of the world, or more stars in our galaxy?
Answer: This is a question that can be investigated by making careful estimates and calculations.
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?
Answer: Nature has produced great variety because living things have different features and adaptations that help them survive.
Is there such a question that makes you curious about the world?
Answer: Yes. For example: Why do shadows change their length during the day?
what happens if…?
Answer: It is an invitation to ask questions and investigate what happens when we change something.
why does dough rise?
Answer: Dough can rise when gases produced during fermentation get trapped inside it.
is the world getting warmer?
Answer: Scientists study temperature and climate data to understand how Earth’s climate is changing.
But what does our body need to stay healthy?
Answer: Our body needs nutritious food, exercise, proper care and protection from infections.
How do we fight these infections?
Answer: We fight infections with a healthy immune system, medicines when needed and vaccines that help protect us.
Have you noticed how a puri or a batura puffs up when placed in hot oil?
Answer: Yes. It puffs up when placed in sufficiently hot oil.
Why does it puff up like a balloon?
Answer: Heating causes moisture inside the dough to form steam, which helps the puri puff up.
And why is one side thinner than the other?
Answer: The difference may be related to uneven dough thickness or how the dough enters the oil. It can be investigated by an experiment.
What are the different things that may change the way a puri puffs up when fried?
Answer: Dough thickness, dough size, type of flour, oil temperature and the way the dough is put into the oil.
Did the oil splatter, smell, or smoke?
Answer: These are observations that should be recorded during the experiment.
Do puris puff better when made fresh or from stored dough?
Answer: This can be found out by comparing fresh and stored dough under the same conditions.
What happens if I prick a hole in the puri before frying?
Answer: The puri may not puff in the same way because the hole can allow steam to escape. This can be tested by an experiment.
Important Terms
| Term | Easy Meaning |
|---|---|
| Curiosity | A desire to know or understand something. |
| Investigation | A planned search for an answer to a question. |
| Observation | Carefully noticing what happens. |
| Experiment | A planned test used to investigate a question. |
| Variable | A factor that can be changed in an experiment. |
| Measurement | A value found using a measuring tool or scale. |
| Ecosystem | Living organisms and their interaction with their surroundings. |
| Climate | The usual pattern of weather of a place over a long period. |
Quick Revision
Curiosity leads us to ask questions.
Observation helps us notice what happens.
Experimentation helps us test our ideas.
Measurement gives us useful data.
Recording helps us compare results.
Investigation can lead to new questions.
Think Like a Young Scientist!
Ask questions. Observe carefully. Experiment thoughtfully. Record what you find. Then ask new questions.
Curiosity + Observation + Experimentation = Scientific Investigation
Prepare with this NCERT Curiosity worksheet for Chapter 1, The worksheet includes important questions and revision exercises to help students understand key concepts, practise what they have learned, and prepare effectively for class tests and exams.
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