Tell Me How : How Were The Egypian Pyramids Built?

Pyramid building developed slowly in ancient Egypt. The first pyramids were simple structures called mastabas, which were platforms built over the tombs of importants people. Over the years further levels were added, until a structure called a step pyramid was produced.

In later pyramids, the steps were filled in to produce the smooth conical shape of the famous Pyramids at Giza that we can see today. Pyramid building became an important part of the Egyptian civilization. Egyptians believed that pyramids offered a pathway to heaven for their rulers, the pharoahs, who were buried with items they might need for the afterlife.

Tell Me How : How Fast Does The Earth Move?

The Earth has two motions – it spins on its own axis and it orbits around the Sun. Its rotation about an axis causes the rising and setting of the Sun, Moon and stars and the changes from day to night. One complete turn of the Earth actually takes 23 hours, 56 minutes and 4.091 seconds. There are tiny variations because of the friction of ocean tides and the changes in the Earth's crust.

The Earth also moves around the Sun and at some points it is closer to the Sun than at others. The Earth and all planets move in their orbit at a speed that depends on the distance they are from the Sun. A planet moves faster when it is closer to the Sun than when it is farther away. The orbital speed varies therefore between 18.8 miles per second to 18.2 miles per second.

Tell Me How : How Does A Caterpillar Become A Butterfly

During her lifetime a female butterfly can lay from 100 to several thousand eggs. She is very careful to lay these eggs near the kind of plant that will be useful to her offspring later.

These eggs will hatch into tiny, wormlike grubs called 'caterpillar lavae' which begin to feed and grow immediately. They will shed their skins several times.

When the caterpillar feels it is time for a change. It spins a little button of silk to which it clings. It lands head down and shed its caterpillar skin. It then appears as a pupa or chrysalis.

The pupa or chrysalis may sleep for some weeks or months. During this time it is undergoing a change, so that when it emerges from its chrysalis skin, it is a butterfly.

It will spread its wings so they can dry and become firm before it will attempt to fly.