1.Tina was trying to burn a paper using sunlight, she have different kinds of mirrors and lenses in her hand .But she doesn’t know which one to select from them .Can you help Tina to select the best options from the mirrors and lenses she have. Justify your answer.
2.Classify the following processes into physical or chemical changes.
(a) Beating of aluminium metal to make aluminium foil
(b) Digestion of food
(c) Cutting of a log of wood into pieces
(d) Burning of crackers
3.The animals living in rainforest adapt themselves to the climate present there. How are
they adapted to the climatic conditions present in tropical rain forest?
Answers
Answer:
a( is the correct digestion of food
Answer:
convex lens
Explanation:
1.
She should select Convex lenses brcause it concentrates the light energy to one spot on the paper so that the heat energy accumulates on that one small spot of paper. As the heat increases, combustion will occur when the spot becomes too hot and the paper will burn.
2.
Firstly, we need to understand what chemical and physical changes are:
Physical change – The type of change in which the physical properties of a material change. It can be changed in shape, state of matter, colour, density, size, odour, solubility, etc. During this change, only the physical traits of the substances are changed.
Chemical change – A substance is said to undergo a chemical change when the chemical properties of a substance alter. As a result, there is either formation or breaking of atomic bonds at the molecular level.
(i) The beating of aluminium metal to make aluminium foil – Physical change
(ii) Digestion of food – Chemical change
(iii) Cutting of a log of wood into pieces – Physical change
(iv) Burning of crackers – Chemical change
3.
Adaptation can be defined as the physical or behavioural characteristic of an organism that helps an organism to survive better in the surrounding environment. All animals adapt a few features for their smooth survival in the residing environment. some of these features are mentioned below-
- Many animals have adapted to the unique conditions of the tropical rainforests.
- The sloth uses camouflage and moves very slowly to make it difficult for predators to spot.
- The spider monkey has long, strong limbs to help it to climb through the rainforest trees.
- Elephants survival and adaptive features are-
- They have a strong sense of smell and uses their trunk for smell.
- They also use their trunk to hold food.
- They have long ears which help them in keeping cool in a hot and humid climate.
- Long ears help them in hearing the very soft sounds.
- They have thickly padded feet which help them in moving silently.