This blog is managed by Song Hock Chye, author of Improve Your Thinking Skills in Maths (P1-P3 series), which is published and distributed by EPH.

## Tuesday, December 11, 2007

### Has the Mystery of Stonehenge been solved?

Watch this incredible video of how one man moves tons of blocks and created a mini Stonehenge in his backyard. The simplest of tools and knowledge of science were used - levers and gravity.

The topic of Simple Machines is taught in Primary 5 Science. It is a PSLE Science Topic.

One of the machines in the P5 Science syllabus is the lever. One of the functions of the lever is to help us move heavy objects. When the fulcrum is placed nearer to the load, compared to the effort, only a small effort is needed to move a larger load.

The video is a testimony that a small force can move heavy objects with the help of the simple lever.

Note that in the "see-saw" scene, which uses the lever principle, a small load is added on one side of the beam so that one side of the beam tilts towards the ground. The builder then raises the fulcrum and the beam is hence, raised.

In the scene where the beam is raised vertically, again, a small load is placed on one side of the beam, causing it to tilt towards the vertical position. Again, the principle of the lever is used.

In an earlier early scene where the builder moves the block in a circle, the principle of the lever is used yet again. He places a rock (the fulcrum) near the centre of the block (the load). In this case, the load is in between the fulcrum and the effort, unlike the other two examples, where the fulcrum is in the centre.

Again, note that the distance between the load and fulcrum is still much smaller than the distance between the effort and the fulcrum, enabling a small effort to move a much larger load.

An illustration is shown below.

Some information about Stonehenge.

http://dictionary.reference.com/browse/stonehenge

Stone·henge
a prehistoric monument on Salisbury Plain, Wiltshire, England, consisting of a large circle of megaliths surrounding a smaller circle and four massive trilithons; dating to late Neolithic and early Bronze Age times (c1700–1200 b.c.) and believed to have been connected with a sun cult or used for astronomical observation