Question

1. A)Define the terms (a) Sedimentation. (b) decantation,
B) Which of the two will dissolve more sugar : cold water or warm water? Why?
2. Which part of the human body are protected by the following ?

A. Skull
B. Ribcage. C. Backbone
3. Draw a labelled sketch of a torch Where does a torch get electricity from? Why do we need a
switch in the torch?

4. a) What is meant by biodegradable garbage and non biodegradable garbage? Give two example of
each type of garbage?
b) Give two advantages of recycling old newspapers.​

Answer 1

Answer:

1A) a)Sedimentation is the tendency for particles in suspension to settle out of the fluid in which they are entrained and come to rest against a barrier. Settling is the falling of suspended particles through the liquid, whereas sedimentation is the termination of the settling process.

b) Decantation is a process for the separation of mixtures of immiscible liquids or of a liquid and a solid mixture such as a suspension.

B) Sugar dissolves faster in hot water than it does in cold water because hot water has more energy than cold water. When water is heated, the molecules gain energy and, thus, move faster. As they move faster, they come into contact with the sugar more often, causing it to dissolve faster.

2A. Skull

3.Cells (battery) are a source of energy for the torch. Chemical energy is stored in the battery which is changed into electrical energy and then light energy as the light glows. An electric circuit is a pathway that allows electricity to flow or a system that allows electrical energy to move. An electric circuit consist of a cell, a torch bulb and two wires which makes the bulb light up. If we want to turn the bulb on' and off easily, we should add a switch in the circuit.  The circuit is incomplete  due to which electricity does not flow in the circuit in this case. So the bulb does not light up.

4a) Biodegradable material contains food waste like vegetable and fruit peels, dead plants and animals, egg shells, chicken, garden waste paper materials, etc. Non-biodegradable things include of plastics, polystyrene, plastic, metals, and aluminum cans, toxic chemicals, paints, tyres, etc.

EXAMPLE -a) Recyclable Waste b) Green Waste.

b) The advantages of recycling paper include saving energy, water and landfill space. Paper recycling reduces greenhouse gas emissions and the recycled fiber is a sustainable, cost-saving resource for making new paper products.

ANSWER 3