Experimenting with pencil.

Wednesday (24/03/2010)

a) Observation
l The kids recalled what they saw during their trip yesterday. Chun Kit remembered about the Police Museum while Devin remembered the National Museum.
l We were lucky that we saw a lot of things related to our current lessons on “Scientist”. The various stones dug showed that they could be of various colours from the Earth Core or the kids referred to as stomach.
l Thus, we watched a video clip again about the Neolithics writing culture. Xing Tong said that writing on paper is much easier than on stones. Thus, different tools were created to ease writing.

b) It became a stone!
l That was Jing Kai’s remark. The mud clay which the kids wrote on Tuesday evening were still soft at writing or drawing. Today, it became hard and Shi Jie tried writing on them but very difficult. They touched their stones, analysed them, juggling them.
Teacher: Why did it become hard?
Shi Jie: Because you removed the plastic wrapper.
Yun Wen: There is no more water. Water makes it soft.
Teacher: Where do clay come from?
Qian Joe: Near the grass. Teacher: Good! Some is near the river. What is actually mud?
l They learnt that mud clay is a type of stone on the top layer of the Earth and some is within 3 km deep down the ground.
l Teacher: What are the writing tools for today?
l Paper and various pencils. Kids guessed that pencils are made from trees. Thus, we watched a video clip on “The Making of pencils”.
l They were amazed to see that the pencil lead is actually long cylinder shape. The pencil leads were first made by crushing the granites. Then, colours were added for making colour pencils. After molding as long cylinder, they were put in between 2 pieces of wood by machines. Then, they were either packed by hands or machines. Wow, it was quite a challenging process.

c) Experimenting with pencil.
l We observed the pencil and I cut opened it. It was quite tough and yes…we saw the long lead. Thus, a pencil consists of 2 parts: the long lead and the wood part. Why can’t it just consist of the lead? They said because the lead is easily broken.
l Who invented pencils? The kids guessed and guessed the different jobs but finally Jun Hong guessed correctly. It was two carpenters who were husband and wife. However, they made pencil the difficult way. They took a piece of wood and dug the inner side of the wood. Then, a piece of lead was inserted slowly. Sometimes, they had to modify the lead just to fit the wood case.
l Later, scientists invented machines that made two piece of wood. Each wood has got a curve so that the lead could be placed in between before sandwiching the woods together.

d) National Anthem: Negaraku
* We practised the National Anthem to reinforce the lyrics. I reminded them of “discipline” as informed by the police officer who worked in the museum. Thus, they stood straight and sang seriously while saluting.