Science Amoung Us ! Part 3

64: Which common items at home show the principle of wheel and axle?

The door knob and the egg beater show two parallel uses of the combination of wheel and axle.

65: How do whistles generate sound?

In a whistle the vibrating system is the air itself. As you blow the whistle, vortexes develop which generate a sound field with a maximum at right angles to their path.

66: At the sunset, the Sun looks dull red. Why?

On the horizon the sunlight has to pass through a greater distance of dust-laden atmosphere. In doing so the short wave-length light is more strongly scattered and the longer wave-length red component of white light manages to get past the obstructing particles more easily.

67: Why do you throw discuss with spin?

The discuss attains gyroscopic stabilization in flight by the spinning action. The spinning action also causes the plane of discuss to remain virtually constant throughout its flight.

68: How does a natural illusion such as mirage occur?

For mirage to happen, a layer of warm air must be sandwiched between two layers of cooler air.

69: Can sand dunes move?

Loose sand is blown by the wind and piles up in wave-shaped formations called dunes. Sand dunes can travel across that desert like waves across an ocean.

70: Thieves have been known to use liquid nitrogen to break locks. How?

Cooling the lock changes its behaviour so dramatically. At low temperatures the dislocations cannot move to assist slip.

71: Why are some people left-handed?

Its Because there the right side of the brain is dominant , that why they are left-handed. Most people are right-handed as their left-side of the brain is dominant. 

72: Why on a clear sunny day there is little wind?

The ground is uniformly heated and without temperature differences heat would not naturally flow. Similar heat flow is that powers a heat engine such as the winds

73: Animals do notice earthquake much earlier or before it can be detected? 

Although different animals seem to respond to different early warning signs, many of them may feel the accumulation of positive electrical ions in the air.

74: How is that milk when overheated flows out of the vessel onto the stove top?

As you heat the vessel of milk, the milk no longer fits in the vessel and so it overflows.

75: Why do shadows happen?

Light travels in straight lines called rays. When the rays hit something they cannot shine through, the light is blocked and a dark shadow forms on the other side.

76: Can we see atoms?

Atoms are the smallest pieces of matter, so we cant see them with our eyes, but atoms can be seen individually under very powerful electron microscopes.

77: Do you have electricity in your body?

All living have beings electricity in there body , There are millions of tiny electrical currents and pulses passing naturally through the body all the time. 

78: How far can you go in an hour?

If you keep walking for an hour without stopping to take rest, your own two legs will carry you about 4 kilometers.

79: Why certain thermal or mineral springs possess therapeutic properties?

It is generally the minerals dissolved in the water that are the active ingredient. As it goes through hot rocks, water collects rare gases and traces of radioactive elements which give it this therapeutic effect.

80: How do birds create their beautiful colours?

A typical bird's feathers are coloured from pigments produced by the bird itself in its skin or produced from something it has eaten. Peacocks among others have feathers with a metallic sheen of ever-changing colours. This is because of the way special feather filaments distort light.

81: Bottling companies never fill their bottles completely full of liquid. Why not?

If a full bottle is heated the liquid inside will expand more than the glass and it will push the top off the bottle.

82: Which conic curve you will see whenever you water a lawn with a hose?

It is parabola.

83: Why sleep really is important?

Sleep is so important that we can survive longer without food than we can without sleep. When we sleep, our pulses rate and blood pressure drop, and our breathing slows. This gives our body and brain a chance to rest.

84: Why the Perspex rod even when tied into a knot can be seen to be conducting light through it?

All the rays which are forced into the one end of the rod are reflected many times by total internal reflection before they finally emerge at the other end.

85: What is the ‘mind's eye'?

It is the place where we can imagine scenes and views that our eyes might see-even with our eyes closed.