The World of Metals and Non-metals — Science STD 7 — Question

What is the effect of acids and bases on blue and red litmus paper?

What kind of toilets are in aeroplanes and trains?

In a mirror, I can also see my face. Is that also due to the reflection of light?

Paheli observed that most of the fish in the pond of her village were gradually dying. She also observed that the waste of a factory in their village is flowing into the pond which probably caused the fish to die. If the factory waste is acidic in nature, how can it be neutralised?

Boojho wants to know how plants prepare their own food?

Name the phenomenon that is involved in the formation of image of an object by a concave mirror.

Why ice floats on water?

What direction does the Sun appear to move in the sky?

Algae are green in colour. Why?

What do you mean by animal nutrition?