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Wednesday, June 24, 2009

Chemistry Week - Laboratory Experience

We attended a series of laboratory sessions at the Singapore Science Centre during their Chemistry Week. Most of the workshops used concepts in Chemistry learnt at the Secondary 3/4 level. Of course, my 8 year-olds don't get it all! But they had fun just "playing" with the apparatus. ;-)

For the sake of future reference, I will go ahead with noting down the specifics of what was done.

Workshop 1 - Sulfur Dioxide and its Role in Preserving Food

What we did :- We tested for the presences of SO2. Hydrogen peroxide was added to food samples (preserved mango, dried sour plum, preserved papaya, raisins, potato chips, fruit juice). This causes SO2 to be oxidised to form sulphates. This sulphate will precipitate out as barium sulphate when barium chloride is added.

My observation :- Boys got the droppers all mixed up and in the process contaminated the solutions!

Workshop 2 - Recycle Paper - Transform Newspaper to New Paper

What we did :- We blended newspaper shreds in a blender with some water. The resultant pulp was gently laid on a mesh that is submerged in a tray of water. The pulp is spread evenly to dry.

Some dried flowers were sprinkled throughout.

We had some leftover pulp, so we made a smaller circular shaped paper.

My observation :- This is the most straight forward of all the workshops. The boys needed to learn that "more doesn't mean better"... I had to remove most of the dried flower they "dumped" onto the paper.

Workshop 3 - Hydrogen Fuel Cell

What we did :- We produced hydrogen gas by reacting magnesium with hydrochloric acid. Hydrogen gas was tested using a glowing splinter.

Too slow in preparing the glowing splint. Ops... fingers too small to stopper over test-tube opening, so most of the hydrogen escaped! ... Managed to get a soft "pop"sound (positive test for hydrogen). Phew!

The set up here was used to electrolyse water.

Green solution of Universal Indicator was added into the water. We observe that the colours at the two graphite electrodes were different. The indicator cahnged to orange (acidic) on the anode (left arm) and violet on the cathode (right arm).

The electrode reactions are as follows:
at the anode:
2H2O(l) → O2(g) + 4H+(aq) + 4e–
at the cathode:
4H2O(l) + 4e– → 2H2(g) + 4OH–(aq)
2H2O(l) → O2(g) + 2H2(g)

The aim of showing the children the electrolysis of water is to show the working principles of a hydrogen fuel cell. The electron gradient produced can be be channelled through an electrical circuit.

Workshop 4 - Green Chemistry - Balance with Nature

What we did :- We investigated the greenhouse effect of carbon dioxide. Two identical set up like this was set up.

Carbon dioxide was put in one of the boxes. The thermometer poked into the box allowed temperature in there to be taken over a period of 8 minutes after the lamp above it has been switched on. The temperature gradient was significantly higher in the box with carbon dioxide.

This was another experiment where we investigated on the effects of various solution on shells. You can see that there is a hole in the middle of the shell on the left. That is the result of submerging it in hydrochloric acid. This experiment aims to show the effect of acid rain.

Conclusion : I realized that my boys had a lot to learn about basic laboratory skills! These include measuring, planning and general apparatus handling. I found a simple lab sheet on Laboratory Safety and Measurement that we can work through at home. Alright, more hands-on session at home from now on...

Sunday, June 21, 2009

Horse Unit Study (part 5) - Drawing Horses

For Art, we were broke away from our usual and galloped off on horses! Let me explain...

We were in the mood to draw horses since we have been reading so much about them. But horses aren't exactly the easiest animal to draw. So I pulled out some of my art books to see what I could put together. I read from How to Draw Animals by Jack Hamm. This book is published in the 1960s but yet the clarity of its instructions far surpasses that of more recent how-to books on the same subject.

What started out as a simple copying of horses unfolded into many successive sessions on animal drawing!

We started working from the beginning of the book where we learned about the shapes found in a generalized animal. We then learn how to put those basic shapes together when we look at an animal.

Here are some outlines we copied from the book. Notice the shoulder muscles, hip muscles and rib cage. These outlines are supposed to help in later shading and rendering of other surface details.

Shading of a generalized animal body was the emphasis for the next few sessions. It really gives the drawing depth and perspective.

Here's an attempt at applying the above concepts. I let my boys try outlining the animals from looking at photographs of animals. I wanted to see if they understood the concept. This is what they produced. Here is my boy's drawing of the basic outline of a donkey. He looked at a photograph in our Apologia Zoology 3 book.

The later part of Hamm's book focuses on different animal types and the usual challenges of drawing these animals. We jumped ahead to the section on Horses. (Couldn't wait!) We copied some of the horse drawings in that section.

Then each of us selected a picture of a horse from one of our other books to copy. Here are my boy's outlines. This was B's sketch from James Herriot's Treasury for Children.

This is D's mustang sketched from Album of Horses by Marguerite Henry.

Drawing and colouring are two separate skills. In the past, I noticed that my boys will be very discouraged when their colouring "ruined" their nicely drawn pictures. This time, I decided to make photocopies of their drawing for them to colour on. This is so that credit can be given to the drawing as well as the colouring; and each having something to show for. We used oil pastels. I joined in the fun too using my boys' drawings.

Drawing animals is indeed very challenging. A mistake in proportion can make a deer look like a dog, or a horse like a cow! For a long time, I myself have shied away from drawing animals. I am now glad I overcome my own phobia and gave it a try because I am pleasantly surprised at my boys' enthusiasm. I guess children just have a natural affinity for animals. I now wished I had done this little off tangent project sooner when we still had our zoo membership!

Wednesday, June 17, 2009

Science :Botany - Ferns

I found it difficult to complete this chapter on ferns without mentioning the concept of the alternation of generations in plants. In the end, I decided to introduce it to my boys. These are some useful sites:
My objective is to expose them to the concept. I didn't want to overload them with technical terms.

I found a good diagram in one of my old Biology books called Botany: An Introduction to Plant Biology by Mauseth. (Here is another good diagram.) It shows the haploid and diploid parts of the fern in its life cycle. I found the easiest way to get my boys to understand this complex concept was to let them colour the diagram; using yellow colour to indicate the parts that are haploid (with one set of genes) and green colour for the diploid(with two sets of genes) parts. The "ah-ha" moment came as they were colouring.

From there, I could then further make a comparison between the spores of the ferns and the seed of flowering plants. They are not quite analogous. The spore is haploid while the seed is diploid, the result of a fertilization process.

We collected sporangium from our fern to view under our Brock Magiscope (mag:200x). I managed to capture it on my camera just by positioning the camera directly over the eyepiece!

You can see the thin side walls of the sporangium and the very faint outlines of the spores within. The cells surrounding have jointed rings (annulus) that will strighten hygroscopically to break the thin side walls, throwing out the numerous spores within. We left the whole set up as is to continue with our other activities for school. Three hours later, this was what we saw. The sporangium opened!

Visit Rumphius Science Webpage to learn more about how we approach Science in our homeschool.

Tuesday, June 16, 2009

Science : Botany - Gymnosperms

We learned about the different types of gymnosperms. Those that bear pollen cones or seed cones are the conifers. Those that bear berry-like cones are like junipers and yews. Then there are special ones that don't really bear cones but still have "naked" seeds, as is the characteristics of all gymnosperm. They are the ginkos and cycads.

One section focused on Softwood versus Hardwood. I proceeded to read a picture book called Woodlore by Cameron Miller and Dominique Falla. I picked this book up years ago in a garage sale. I was naturally attracted to its contents as my home has always been stocked with wood of all types. It starts out like this:

Yew trees grown throughout the ages,
Have the wood the bowyers favors.

Maple and spruce are always kings

For makers of lutes and violins.

This book is written in poetic form telling which types of wood are best for what purposes. Interesting!

The Elementary Apologia Science books have sections called Creation Confirmation. I love these as they are so important in building up our faith. Here's my boys narration for one of such sections in this chapter:
The world-wide Flood happened about 4700 years ago. We know that by counting the generations of people in the Bible. All trees will die in the world-wide flood. Seeds will still survive. All trees alive now must have grown after the Flood. The oldest living tree is 4700 years old. That is a good evidence that the Flood took place at about 4700 years ago.

Visit Rumphius Science Webpage to learn more about how we approach Science in our homeschool.

Monday, June 15, 2009

History of China... Preliminary Plans

We visited the Asian Civilizations Museum three weekends ago to view the Kangxi Emperor Exhibition: Treasures from the Forbidden City. It was International Museum day and that meant the public could enter the museum for free!

My personal favourite object in the exhibition is a painting (on hand-scroll) that is 22 metres in length, depicting Kangxi emperor on his second inspection tour. We had fun studying the details of the painting and trying to spy where the emperor was. It's a pity we were not allowed to take pictures in the exhibition...

We spend some time musing at the not-so-ordinary family tree- what with 50 wives and 55 children!

Our interest in the History of China was sparked off and I am now researching to see how I can incorporate Chinese history into our History curriculum. That was my original plan anyway. I just haven't sat down to seriously do my research.

There is a spatter of Chinese history in Story of the World, but in my opinion, too superficial. Being Chinese, we ought to know more. It is a pity our command of the Chinese language isn't good enough for us to use Chinese history books (or any primary sources), we would have to resort to those in English instead.

Here are some things I've managed to find so far...

An Amazon Listmania provided me with a list of books I could use to explore deeper. Two books stood out from the rest; The Story of Ancient China (from Neolithic times through the Tang Dynasty) and its sequel China's Later Dynasties (mainly on China's last four dynasties - the Song, the Yuan, the Ming, and the Qing) both by Suzanne Strauss Art. They are written for middle school students (ages 10-14 yrs old) and look like wonderful spine books I could use for our study on the History of China!

Here are some websites with important information that is geared for children (I will add on to this list if I find more useful sites):

Post update on 12 July:
I found a unit study called Ancient China: To the Great Wall and Beyond by Judy Wilcox. This is a twelve-week study that brings you through eleven key dynasties through reading and project work. One interesting point brought up in reviews (1 & 2) was the fact that the student is challenged to research and make biblical contrast. Efforts were even made to relate historical events in China to the biblical timeline for context. This looks really promising!

Post update on 14 July:
Here are 2 books available as etext on Chinese History:
1. China's History by William E. Griffis
2. The Story of China by R. Van Bergen

Wednesday, June 3, 2009

Science : Botany - Trees

This post highlights snippets of what we did for the chapter on Trees apart from our usual read aloud and narration of our Botany book.

We wanted to find out more about heartwood and sapwood. We found this site (Wood Magic) with very clear explanation. In fact we completed a notebook page based on our read alouds through these pages.

I made a set of 3-part cards for Twig Anatomy while my boys made theirs on the new vocabulary for this chapter. I just could not find the time to prepare these before hand. I have decided to keep it simple; no fancy coloured borders, no printed words, no lamination. I just coloured the respective parts of the twig and wrote the name of the parts down!

We reviewed our old 3-part cards for flower anatomy because my boys have forgotten that. I needed them to know because this chapter introduced the concept of "imperfect flower". Cannot expect them to know what is an imperfect flower if they don't first know what is a perfect one. Just love these 3-part cards. They are so convenient to pull out for reviews whenever we need it.

I decided to teach my boys the shapes of tree crowns. Different websites use different terminologies so I thought I'd just introduced them all. (They can be seen mainly in these two pictures: 1 and 2)
1. round/spherical
2. oval
3. V-shaped/vase/funnel
4. cone/pyramidal
5. columnar/tube
6. spreading/umbrella
7. weeping
8. irregular
This post is long overdue. I had initially wanted to follow this chapter up with an Adopt a Tree project that would continue for at least a year. However, some circumstantial changes at home has caused me to think we might not be living here for that long. This has caused me to procrastinate for quite some time; and was tempted to abort the plan altogether.

My original plan was to observe an adopted tree (within our neighbourhood) regularly over at least a year to see if we can observe any growth change or patterns. I noticed that some trees flower only at certain times of the year and some even shed their leaves almost completely. I am not sure these cycles follow a strict time period, so I thought it would be nice to investigate.

I later decided to allow my boys to make their observations anyway. This would serve to review many of the concepts covered in previous chapters. The following observations were made of their adopted tree. These will also be the guidelines for any of our future tree study:
1. tree - shape, height, branching patterns, height of lowest branch,
2. trunk - girth, bark texture
3. leaf - shape, size, margins, venation
4. flower - colour, growth pattern, petal arrangement, predict pollinator
5. fruit - colour, type, predict dispersal mode

Visit Rumphius Science Webpage to learn more about how we approach Science in our homeschool.
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