1. Exploring the Investigative World of Science

This is the opening chapter of the Grade 8 textbook Curiosity. It has no exercise. It invites us into the investigative world of science.

In Grade 6 we learnt that science begins with wonder. In Grade 7 we learnt that science keeps evolving. In Grade 8 we learn how to find new facts ourselves.

A young investigator:

• asks focused questions,
• designs simple experiments to answer them,
• observes carefully and keeps notes, and
• uses the observations to improve understanding.

• Tiny microorganisms — helpful and harmful.
• Health, food, exercise, medicines and vaccines.
• Heating and magnetic effects of electric current.
• Forces, pressure, winds, storms and cyclones.
• Particles of matter; elements, compounds and mixtures; solutions.
• Light — mirrors and lenses.
• Phases of the Moon and calendars.
• Ecosystems, and what makes the Earth just right for life.

First, we ask a scientific question: What are the different things that may change the way a puri puffs up when fried?

Things we can change or control:

• thickness and size of the rolled dough,
• type of flour (atta, maida, etc.),
• temperature of the hot oil,
• the way the dough is dropped into the oil (vertically, at an angle, slowly).

Things we can observe or measure:

• Does the puri puff up? (yes/no)
• Time taken to puff up (in seconds).
• Does a very thick dough still give a thin side?

Rule of a fair test: change only one thing at a time. Keep all other conditions the same.

For example, to test the effect of oil temperature, use dough circles of the same thickness. Drop them in the same way. Change only the temperature of the oil.

Keep notes of everything you see and sense. Did the oil splatter, smell or smoke? After one round, new questions come up. Do puris puff better from fresh dough? What if we prick a hole before frying?