Reflections on science experiences, laboratory sessions, field work and excursions

This year, I have taken part in many science experiments in the science laboratory, and I would like to share some of my personal experiences in these activities that I have taken part in.

Laboratory sessions and experiments I have taken part in
Throughout the year, I have taken part in various science experiments which took place in the science laboratory. An examples of these sort of activity in Term 1 was getting to know more about the Bunsen burner, and knowing how to operate it. Further activities in Term 2 and 3 required the use of the Bunsen burner, such as separating salt from a mixture of salt and sand, boiling of water, etc. Also, there were other activities such as measuring the heat intensity of two different containers with different colours, etc. Also, there were many different sort of activities according to the practical worksheets we were given. I feel that the idea of having practical worksheets to do while we did the experiments was a good idea, as it was partially to make sure that we learnt from the experiment, well as to make sure that we understood the topic of the experiment (elements, compounds, mixtures, cells, distillation, etc.)
The greatest takeaways from these activities was that they were a fun way to learn our science topics and I feel that this should be the same for next year as well.

Reflections on Termly Personal Performance and Growth Development in Science

This is a reflection on my termly science grades and growth in understanding of science, and how I can improve your grades and keep growing in scientific understanding and interest.

Term 1

For my science test in Term 1, I scored 31/40, which was rounded off to 78/100. This score was an A1, and I feel that my score was quite decent, although I could have done better.

Term 2

For my science test in Term 2, I scored 21.5/40, which was rounded off to 54/100. This score was an C6, and I was not satisfied with my score. I felt that I had not put in my maximum effort and I decided to immediately put a stop to computer gaming, which was disturbing me from my work.

Term 3

For my science test in Term 3, I scored 33.5/40, which was rounded off to 84/100. This score was an A1, and I was happy with my score and felt that putting a stop to gaming had indeed paid off. I told myself to work harder in future, as I knew that I can do well if I try my very best

Term 4

Right now, I have yet to take the science main examination paper in Term 4, and I hope that I can do well and pass with flying colours. My aim is not just to get an A1, but to do the very best I can, and with the maximum effort I put in, I believe that I can achieve what I want and get a good grade.

I feel that getting A1 or the best in class is not the only things that are important, but what is just as important is putting in as much effort as I can and being happy that I have done so.
Also, I feel that understanding the science topics is another important factor. If I do not understand a certain topic, I may not be able to do well in the test however hard I study for it, so I feel that I should ask any topics that I am unsure of.

Issues in teaching and learning science

This is a post about my thoughts and reflections on the topics and issues that I have learnt in the lower secondary science curriculum. 
SI Units
Firstly, I have understood the importance of the SI units. The SI base units refer to the International System of Units and is made up of the following base units and their physical quantities,-
metres for length,
kilograms for mass,
seconds for time
amperes for electric currents,
kelvin for temperature,
candela for luminous intensity, and
mole for the amount of a certain substance.

The main importance of SI units is standardization. The idea is to use the same standard units all over the world. SI units form a coherent set, and they are the only form of units that are globally recognized. They have a clear advantage for establishing a worldwide dialogue, and therefore simplify the teaching of science and technology if everyone uses this system.
I feel that SI units are of significant importance to the study of Science, and I have understood their importance to our daily life.

Difference between weight and density

Density represents a physical property of matter. Every element has a unique density, and the weight of an object depends on gravitational force, which can vary between different objects.

Also, density is typically expressed in grams per milliliter or cubic centimeter, and it remains constant for any particular substance. 

However, the weight of an object varies according to its location in the universe, and the force that gravity exerts on it at that location. For example, an astronaut on the moon would weigh 1/6 of his weight on Earth, which shows that weight varies according to the object's location.

About leaves- starch, cells, and more

Leaves is an interesting topic. They are in different shapes and sizes, and they contain chlorophyll. Even though they are all different in many ways, they have many areas in common.
Starch
All leaves contain starch, unless it is used up. The starch is only present in specific parts of the leaf as shown in the picture above. Leaves have to be boiled in alcohol in order to remove the chlorophyll and make it easier to see the starch turn dark blue when iodine is applied onto it. The leaf has to be put into alcohol and boiled in a boiling tube, but it must not be placed directly under the flame, as alcohol is flammable (picture above). Once the leaf is boiled in alcohol, the chlorophyll will be removed in the solution and the leaf will become white and colourless. It can now be used for iodine testing, as the results can be seen more clearly.
Cells
All leaves are made up of many cells, and they contain chloroplasts, which hold chlorophyll, giving leaves its green and bright colour. Although there are some leaves which are not exactly green in colour, they still contain chlorophyll, as they have a pigment which makes them look the colour they are, red, maple leaf for example. All leaves also have stomata at the underside and top side, as shown in the picture above. They are pores which allow gaseous exchange between the plant and the surrounding air. Stomata consist of guard cells, which regulate the size and opening of the stoma, just like a muscle. The stomata exchange oxygen and carbon dioxide with the surrounding air during respiration and photosynthesis.
Veins
The veins on leaves have an important use. They are the vascular tissue of the leaf and are located in the spongy layer of the mesophyll. they are made up of the xylem and phloem. The xylem is made up of tubes that brings water and minerals from the roots into the leaf. As for the phloem, they are tubes that move sap, with dissolved sucrose out of the leaf.

Cockroach- key to future antibiotics

While I was looking through the newspapers, there was an article about cockroaches going to be used in future antibiotics. Currently, British scientists hope that one of the hardiest insects around, the cockroach, may be used in future antibiotics. As they live in dirty and unhygienic environments, such as sewers and garbage dumps, they have developed a sort of immunity against bacteria over the years.
After going through tests, scientists have discovered that the tissue from the brains and nervous system of the cockroaches had killed more than 90% of the tested bacteria without damaging any human cells. The scientists were not surprised that the insects could naturally secrete their own antimicrobial drugs.
As cockroaches live in unsanitary and harsh environments, they often encounter many different types of bacteria. It would therefore be logical that they developed themselves against micro-organisms.
This topic interests me, as the thought of how an insect as dirty as the cockroach could be used in antibiotics to treat humans is shocking, yet the results of doing that would be very effective.

Cells, Tissues, Organs, Systems

 

Cells, tissues, organs and systems are all important parts of our human body. Cells are all over our body and usually cannot be seen with the naked eye. These cells may vary in type (nerve cell, cheek cell, hair root cell, etc.) Many cells group together to form muscle tissues in our body. These tissues are rich in protein. Examples of tissues in our body are (muscle tissues, and even blood). There are three different major types muscle tissue. The cardiac muscle, skeletal muscle, and visceral muscle. The cardiac muscle is found in the heart, the skeletal muscle in the bones, and the visceral muscle in the arteries, bladder, digestive tract, as well as other organs. The tissues in our body cluster together to form organs, such as the heart, brain, stomach, etc. As mentioned above, the visceral muscle makes up many of the organs in our body. A few organs make up a system, which is required by our body to live. Examples and uses of systems are the digestive system, which breaks down food into simpler substances, the respiratory system, in which oxygen is taken in and digested food is used up as energy, the circulatory system, in which blood is pumped all over the body to transfer oxygen to the various parts of our body, etc. Each and every organ and system plays an important part in our daily lives, and without them, our body cannot survive.

Reverse Osmosis- what it is about

Reverse osmosis is a method of filtration which can remove different types of molecules of different sizes by applying pressure to the solution when it is on one side of a selective membrane. The solute will be retained on the pressurized side of the membrane and the pure solvent will be allowed to pass to the other side. For this process to be carried out, the membrane should not allow large molecules or ions through the pores, but should allow small components of the solution to pass through freely. In other words, the membrane is semi-permeable, thus allowing small substances to pass through while preventing bigger particles from entering.
A common use of reverse osmosis is its use for water purification purposes. Seawater has to be cleared of the salt and other impurities in order to be consumed, so reverse osmosis has to take place to clear out all the impurities and purify the water. The salt particles, along with other dirt particles in the sea water cannot pass through the membrane, however the water particles can, so the salt and dirt particles will gradually be removed from the mixture.
This process is the opposite of osmosis, in which the solvent moves from an area of low solute concentration, through a membrane, to an area of high solute concentration.
The process of reverse osmosis is somewhat similar to membrane filtration. However, membrane filtration includes the use of straining, or size exclusion, so the process can achieve perfect exclusion of particles regardless of the pressure and concentration. On the other hand, reverse osmosis involves a diffusive mechanism so that the separation efficiency depends on the solute concentration, pressure and water flux rate.

Rockets- how they fly in space

I have always wondered how rockets could fly in space, as we all know oxygen is needed for combustion, but there is no oxygen is space. So I researched about this topic, and came up with some interesting results.
I found out that in a rocket's engine, a fuel propellant is burned with an oxidizer propellant to produce large volumes of very hot gas. The hot gas that is ejected from the rocket engine acts as a propellant, and produces thrusts for the rocket, to make it move. The hot gases that are ejected from the engine expand accelerates them until they rush out of the back of the rocket at extremely high speeds, propelling the rocket forwards. During takeoff, however, the rocket makes use of its liquid hydrogen and oxygen tanks to boost themselves out of the Earth's gravitational field.

Iodine- What it can do

Iodine is commonly used in Science Laboratories for various experiments, as it has a good use. It comes in many forms, small crystals, liquid, or even the raw form (chunk of crystal). Iodine can detect if there is starch in a substance when it is applied onto it. It reacts with starch and turns blue-black when put together with starch. If the iodine solution turns dark blue, it represents that starch is detected in the substance. If if does not change its colour and remains brown, it means that starch is not present. Take for example a biscuit, as shown in the picture above. When iodine is applied on it, the solutions turns dark blue at once, meaning that starch is present in the biscuit. However, if iodine is applied onto a piece of fish meat, the colour of the iodine solution will not change and will remain brown, as starch is not present in fish meat. Starch is only present in plant products (flour, potatoes, bread, etc.), and is not present in meat or other products (chicken, plastic, metal, etc.), which means that iodine will
only react and turn blue-black when it comes into contact
with plant products.

Cells- What I learnt

 Today, I have learnt a lot of information about cells, both animal and plant. Firstly, I have learnt that animal cells differ from plant cells greatly, as they lack the presence of a few cell parts. A plant cell has the basic cell parts of - the sap vacuole, the cell wall, the nucleus, the cytoplasm, the cell membrane and the chloroplasts, while an animal cell has the basic cell parts of - many small vacuoles, the nucleus, the cytoplasm and the cell membrane. Other than these parts, plant and animal cells also contain other parts which are more complicated, such as the smooth and rough endoplasmic reticulum, the ribosomes, mitochondria, golgi body, etc. Below is an explanation of the various cell parts as mentioned above-
Sap Vacuole/Small Vacuoles- Stores water, nutrients, and other substances that are not immediately used. It takes up most of the space in a typical plant cell, however, it is small and there is the presence of a few of it in typical animal cells. It stores compounds and helps in plant and animal growth.
Cell Wall (Plant Cell)- Made up of cellulose, and it provides structural support for plant cells. It helps to maintain the cell's rigid shape and it also controls the maximum amount of water that is taken into the cell.
Nucleus- It contains chromosomes, structures made up of genetic information,and is essential for cell division. It regulates other cell activity.
Cytoplasm- It distributes food and oxygen to other parts of the cell, and it fills up and supports the remaining empty spaces left in the cell. It contains mostly dissolved nutrients.
Cell Membrane- It is a semi-permeable layer around the cell which allows waste materials to exit the cell, and allows only certain substances to enter the cell.
Chloroplasts (Plant Cell)- They are found in numbers in plant cells, and store chlorophyll, which is needed for photosynthesis. They are the food producers for the cell.

These are the various basic parts and their functions of plant and animal cells, and they each have their own significance. In cells, 'division of labour' means that each part of the cell has its own specific function, and this will make them specialize in their task and thus, efficiency is increased.

What I Know About Aerobic and Anaerobic Respiration

After being introduced to studying a little on this topic, I became interested to find out more on aerobic and anaerobic respiration. First of all, I have learnt that both of the respiration processes are different in their own ways. In both processes, ATP, or adenosine triphosphate, is involved.
Aerobic Respiration
Aerobic respiration occurs in plants, and scientifically speaking, it is the release of energy from glucose or another organic substance in the presence of oxygen. During aerobic respiration, oxygen is required, and the process is divided into two processes: the Krebs cycle, and the Electron Transport Chain, which produces ATP. The molecules are reduced, receiving high energy electrons, thus representing energy available to do work.

Anaerobic Respiration
This process is very different from aerobic respiration.In anaerobic respiration, organisms produce usable energy in the form of ATP without the presence of oxygen. In other word, it is respiration without the need of oxygen. These organisms are usually bacteria or other micro-organisms which live in environments which lack the presence of oxygen. However, even though oxygen is not involved in this process, it is still a form of respiration, because all three basic steps of respiration are used- glycolysis, the citric acid cycle, and the respiratory chain.

These are the two different forms of respiration, and their differences can be seen from the points stated above.

Post on my feelings towards the recent Gulf of Mexico's oil spill

On the 20th of April, 2010, a sea-floor oil gusher, the Deepwater Horizon drilling rig, run by British Petroleum company exploded due to a malfunction, resulting in the deaths of 11 platform workers and the injury of 17 others. Apart from the deaths and injury, the explosion of the oil rig, caused the Gulf of Mexico oil spill, also referred to as the Deepwater Horizon oil spill. It is the largest marine oil spill in the history of the petroleum industry, as lots of gushing crude oil was emitted from the wellhead (an estimated amount of 53000- 62000 barrels of oil per day). The oil spill caused a lot of damage to the wildlife and marine habitats and also caused the fishing and tourism industries in the Gulf of Mexico to lose business. Many dead fish and turtles have been found along the shores and beaches around the area, as well as birds, including pelicans, with oily and wet wings, faltering their flight. Moreover, the water in the affected area was brown and sticky, affecting the tourism and restaurants in the Gulf, which had seafood on the menu. Most of the marine life was badly affected by the oil in their habitat, and few dared to have seafood at restaurants in the Gulf. Other than the affected marine life, the oil wasted was also in large quantities, which meant a heavy loss of financial capital from the British Petroleum. The BP, being held responsible, has taken a few actions so far. They had shut down the oil well since the 15th of July and they are undergoing operations to remove the drill pipe. Also, after the leak had been spewing for nearly three months, the BP capped the well. They have also launched the test to assess possible damage to the well pipe which runs nearly four kilometers under the sea floor. I feel that these measures taken are helping to solve the problem, and it is good that the BP is implementing these solutions. I hope that the problem will be solved soon, the Gulf waters will return to normal, and that the marine life do not die.