Why north pole and south pole was cold?

Answer 1

Because the Earth is tilted on an axis, the equator is always closest to the sun. The North and South poles are the parts of the Earth furthest away from the sun at all times.

WRONG!

because the earth is tilted on its axis the equator is closest to sun for only a moment twice a year!

The poles are cold for several reasons:

1. The primary reason is because when the sun shines there, it is always at a shallow angle. Even during the summer when the sun never sets, it never gets higher than about 24 ° from the horizon. Note that the day is always hottest when the sun is high in the sky. As it begins to descend towards the horizon, i.e. is at a shallower angle, things begin to cool down even though the sun is still up. Since the sun never gets very high in the sky at the poles, it never warms up much.
2. During the winters at the respective poles, the sun never rises at all - they get no direct sunlight to warm them.
3. Weather patterns do not bring much in the way of warmer winds from warmer areas to help raise the temperatures at the poles
4. In the case of the South Pole, the high elevation makes it even colder; the South Pole sits about 2,800 m (9,186 ft) above sea level. By comparison, most of Europe sits at an elevation of about 300 m (980 ft). North America averages about 720 m. The huge continent of Africa averages about 600 m (2,000 ft) above sea level - although the high southern and eastern plateaus, rarely dip below 600 m (2,000 ft), and have an average elevation of about 1,000 m (3,300 ft).