2008 Gr 11 Biology Field Trip

In September the Gr 11 Biology classes completed a week long field course on Tioman Island. Here they had the opportunity to extend their study of ecology by applying their knowledge to field work on the island. The students studied the coral reef, mangrove, rocky shore and rainforest ecosystems in depth. They completed two major pieces of research which will form part of their Internal Assessment portfolio of work for their IB Diploma.


It was a fantastic week as the photos below show........

Grade 8 WASTE PLASTICS PROJECT

Our class, Ms Carter’s Gr 8 Science class, did a “Waste Plastics Project”. For a week, we had to collect plastics that we were going to throw away and bring them to class. The day we chose to do our tally was on Wednesday, 20/08/2008.

We left all our plastics in a corner of the science lab, and they piled up into a heap as big as a mountain!
Items collected included plastic bottles, containers, snack wrappers, plastic bags and so on. With the help of our fellow classmates, we separated all the collected items
into different categories, and placed them around the lab accordingly.

By the end of the categorizing, there were massive piles of plastic items spread across the desks. Who would have guessed that just twenty families had already amassed such a large amount of plastic waste in just a week?! Imagine just how much more plastic would have been wasted across Singapore!!

TABLE TO SHOW WASTE PLASTICS COLLECTED:




As you can see from the results of our “WASTE PLASTICS PROJECT”, the amount of plastic that is wasted is huge and should be seen as a GREAT cause for concern!

Here are a few ways YOU can help cut down on the amount of waste plastic without drastically altering your lifestyle:

1) When you get takeaway from hawker centres, the vendor will usually pack your food in plastic containers. The next time you get food from the hawker centre, you should bring along the plastic containers you received the last time and ask the vendors to put your food in those you brought instead of giving you more.

2) The next time you go grocery shopping, bring along an eco-friendly cloth bag or a rucksack to put your groceries in, instead of using plastic bags.

3) If you get drinks in plastic bottles, you should reuse those plastic
bottles as your drinking bottles or throw them in the recycling bin.

But the easiest way to cut down on buying drinks packed in plastic bottles is simply not to buy them! Besides, those drinks are nothing but sugar and completely unnecessary anyway!

4) DO NOT USE PLASTIC UTENSILS. Use steel utensils instead.

Now, you have no excuse to waste plastic ever again!

Did you know…??
* Singapore’s landfill sites are located at Ulu Pandan, Pulau Semakau, Senoko, Tuas and Tuas South.

* One of Singapore’s landfill sites, Tuas South, is one of the largest in the world.
Plastic cannot biodegrade. Plastic waste thus takes up a lot of landfill space.

* Pulau Semakau (Singapore’s newest landfill site) is expected to last until 2030 – only slightly over twenty years from now. However, if the amount of waste produced in Singapore continues to rise, the lifespan of the Pulau Semakau landfill might be shorter than expected.

Chlorophyll and Starch in Leaves

On the 24/7/08, Tuesday. Our Grade 10 FIB class, 10RRa learnt a new topic for biology lesson, photosynthesis. To allow us to have a better understanding of how photosynthesis occurs, Dr Hjorth engaged us in an experiment which requires us to test for starch in a piece of leaf.

Our class was then divided into several groups. Whereby we then obtained leaves from various plants and begin on our experiment.
Our group consisted of Yvette, Nicole and Sunshine. Dr Hjorth gave us a piece of leaf that looked distinctively different from the ordinary green leaves. The colour of the leaf was as of such, from the centre, pink, pale yellow, to the edges which are green. According to our knowledge, only the green parts of the leaves contain starch. Yet now we have a leaf with 3 shades, would the coloured parts possibly test positive to starch?

Step 1: First we had to place the leaf in boiling water for a minute to soften it.

Step 2: Once that is done, we place the leaf into a new test-tube with ethanol. Stand the test-tube in a beaker of hot water for around 10 minutes.

Step 3: Wash the leaf in cold water

Step 4: Spread the leaf flat on the Petri dish and cover it with iodine solution. If the leaf turns blue-black, it means starch is present.

After conducting the required steps, we obtained the following results:



As you can see, the places which were green turned blue-black, indicating starch was present where chlorophyll was. The pale coloured parts of the leaf stayed the colour they were, indicating starch was absent. So we can conlude that chlorophyll is involved in photosynthesis producing starch. The reason why a substance like starch is used for storage in plants is because it is insoluble, and does not cause problems like osmosis, unlike glucose.

Making a DNA model!

Constructing a DNA modelThe FIB 10JGo class constructed a DNA model that could be stretched from the third storey in our school all the way down to the first storey, almost touching the ground (see photo below). For the construction, we made about 200 small circular phosphate molecules, 200 pentagonal sugar molecules and 400 rectangular base molecules!!

It was a fun and lively activity, but we did learn a lot about DNA. Or at least, we could cope well with Ms. Carter’s questions afterwards.
DNA stands for deoxyribonucleic acid. We are familiar with DNA in relation to inheritance. For example, we know that DNA has something to do to why offspring often have their parents’ characteristics. Well, that’s correct because DNA is a nucleic acid molecule that carries genetic instructions that is found in all living organisms except some viruses.
In cells of eukaryotic organisms (which have a nucleus in their cells), DNA is found inside the nucleus. Animals (humans are included here), plants, fungi and protists are eukaryotes, so they have their DNA inside their nucleus. Since bacteria do not have a nucleus, they are prokaryotes and their DNA is found in cytoplasm.Now, look at the photo below. It’s a close-up look at our DNA model. The colourful rectangles represent base molecules and contain either one of these letters: T, A, G or C. T stands for thymine, A for adenine, G for guanine and C for cytosine. Notice that T only pairs up with A and G with C. This is the rule of base pairing, i.e. the bases will always pair up this way. Each pair of bases is held together by hydrogen bonds (see the staple between two bases).

The DNA model above looks like a ladder. The phosphates (represented by the yellow circles) join up with sugar molecules (the pentagons) and they make up the uprights of the ladder; the bases make up the rungs. We further twisted the model above into a beautiful double helix (the molecular structure of an actual DNA molecule), so it looked like a spiral staircase.


Petrus Bosa Layarda

Year 9 research: Cutting edge applications of nanotechnology

Diamond and graphite are two well-known forms of carbon. In 1985 scientists discovered a third form of carbon based on 60 atoms bonded in a football-like structure. Scientists called this 'buckminsterfullerene', or 'buckyball'. This started a search for other carbon structures. In 1991 a Japanese scientist called Sumio Iijima found carbon nanotubes. These are about 10 000 times thinner than a human hair, made from carbon atoms bonded in sheets and rolled into tubes. Scientists are working to find out more about carbon nanotubes and what they could be used for.

What do nanotubes look like?

Images Top to bottom: carbon nanotubes, a colored image of a nanotube, a ‘buckyball’

Year 9 have been researching the current applications of nanotubes and other areas of nanotechnology - the science of building machines at sub-atomic level.

Scott Heng, Paul Wong, Scott Lim and Qin Yi researched the most recent applications of nano-tubes and discovered that they are 50 times stronger than steel and are currently being developed as molecular sized wires in electronic circuitry. They explained how these molecular sized nano-wires are currently being developed to produce miniature gadgets.

Maria, Antonia and Nicole discovered that a microscopic layer of titanium dioxide (so thin it is invisible) is being used to coat clothing. This titanium oxide reacts with oxygen, creating a chain reaction that eventually results in the removal of dirt particles without washing. As the girls pointed out ‘great for busy people who don’t have time to clean!’

Anthony, Yuan Min and Ian researched the use of nano-sized particles of zinc oxide in sunscreen. Zinc oxide has been used as sunblock for many years, though, it has never become popular as it forms thick white patches on the skin. Scientists have discovered that if zinc oxide is particles are arranged in a single nano-sized layer, it is does not scatter visible light and becomes transparent, preventing the formation of an unsightly white layer .

Mrs Kitchener

Parents take a Science lesson!!

On April 19 prospective Yr 7 parents visited SJI International to see how we teach. They were involved in several lessons from all subjects and the photos below show them engaed in a science lesson. Some made comment that it was the first time they had been in a science lab for more than 30 years! As you can see they seemed to really enjoy being back.

The scanning electron microscope

The scanning electron microscope (SEM) is capable of creating images of the surfaces of objects at very high magnification. It's amazing the detail that can be seen using this piece of equipment.

Have a look at these images and try to guess what they are of (the answers are at the bottom of this post)

1. (image width approx. 1mm)

2. (image width approx. 0.010mm)

3. (width of bottom image 0.025mm)

4. (image width 1mm)

5. (image width 0.015mm)



Answers:

1. A seed of the tabacco plant

2. Pollen grains from many types of flowers

3. E = red blood cells L=white blood cell

4. The gills of a fish

5. Cholera bacteria