Term 3~

Term 3! Another rocking term!

This term, the science topics are getting harder! There are big topics such as Digestion, Osmosis and Diffusion! Must work hard!

Cells

There are two kind of cells we have learnt, an animal cell and a plant cell.

Parts of a Cell and their Functions

For both animal cell and plant cell:


Cell Membrane: The cell membrane is the outer most part of the cell which encloses all the other cell organelles. It controls the influx of the nutrients and minerals in and out of the cell.

Cell Cytoplasm: Cytoplasm is mainly made up of water and protein material. The cytoplasm is the key site wherein all life processes occur.

Nucleus: Cell nucleus is supposed to be the brain or the control center of the cell and thus one of the most important animal cell parts. It contains DNA and the chromosomes.

Vacuoles: Smaller gas and membrane vacuoles filled with fluids and water are present in animal cells.
Their main function is storage.

Mitochondria: Mitochondria are the so call engine house of the cells. They combines Oxygen with glucose to form energy 

For Plant cell only:

Chloroplast: They are organelles responsible for photosynthetic activity. They contains chlorophyll,which helps in harvesting light energy and converting it to chemical energy for the cells.

Cell Wall: Cell wall is the outermost tough and rigid layer of a plant cell. The prime functions of cell wall are protection, giving structural support and helping in the filter mechanism. 

Diffusion and Osmosis

Diffusion: It is the spread of particles through random motion from regions of higher concentration to regions of lower concentration. 

Osmosis:  the movement of solvent molecules through a selectively permeable membrane into a region of higher solute concentration.

Term 2~

Yay! It's term 2! Another wonderful term in HCI.

Our Science lesson still ROCKzzz !

First, we learnt about the Kinetic particle theory.

The kinetic particle theory states that all matter is made up of a large number of tiny atoms or molecules which are in continuous motion.

Three States of Matter

Solid:

The molecules of the solid are packed together tightly. They have strong attraction and repelling force among themselves which prevent them from collapsing.

That's why  the solid is always is fixed shape and have fixed volume. Solid cannot be compressed because there is very little gaps between the molecules.

Liquid:

The molecules of the solid are further apart than the solid. However, the molecules of the liquid can move around within the liquid.

That's why liquid do not have fix shape. The strong attraction force is still able to keep the liquid together so the liquid has a definite volume.

Gas:

The molecules of the gas are far apart. They move randomly with high speed.

Therefore, a gas do not have definite shape and volume and can be compressed easily due to the huge space between the molecules.

Then, we learnt about Element, Compound and mixture.

Elements:

Elements are the basic building block of matter , they may exist as atoms or molecule. It cannot be broken into simpler substance by any physical or chemical methods. The elements are grouped into a periodic table

Compound:

A compound is two or more elements that are chemically  joined  together. They are formed by fixed proportion and do not have the properties of its constituent elements.

Compound can be separated by chemical methods.

Mixture:

Elements in mixture is not combined together. Hence, mixture is not formed by fix proportion and have the properties of its constituent  elements. They can be broken down into simpler substances by physical methods.

Solution and Suspention

(a) is the molecules of a solution

(b) is the molecules of a suspension

Solution

a solution is a homogeneous mixture which the solute dissolves in a solvent completely.

There are three types of solutions we have learnt:

Dilute solution: There is little amount of solute dissolved inside the solvent.

Concentrated solution: There is a large amount of solute dissolved inside the solvent.

Saturated solution: Maximum amount of solute dissolved inside the solvent. At this stage no solute can be dissolved anymore.

Suspension: a suspension is a non-homeogenous mixture which the solute cannot be dissolve in the solvent.

Solubility: the amount solute that can be dissolved in a given amount of solvent.

Factors that will affect solubility:

• Type of solvent
• Type of solute
• Temperature

Rate of dissolving: the time taken for the solute to dissolve completely in solvent.

Factors that will affect the rate of dissolving:

• Size of the solute
• Temperature of solution
• Rate of stirring

What will happen if we get a mixture or a compound and we want to know what do they contain?

Yes, we can use Separation Techniques.

These are the different techniques used:

Paper Chromatography
It is used to separate a mixture which is based on the extent of solubility in a given solvent.

Filtration

It is used for mixtures that contain liquids and insoluble solids

Magnetic Attraction

Used to separate mixtures of magnetic and non-magnetic materials.

Simple distillation

It is used yo separate a solid-liquid solution.

Crystallization

It is used to recover pure soluble solid from a solution

Term 1~

OMG! First term in HCI and.... it's wonderful. On our first Science Lesson, we met our Science Teacher Ms Nada !~ :) And guess what.........she ROCKzzz !!

We started off with the Introduction to Science& Technology and the topics we will be learning for the term.
Then, Ms Nada talked about the DOs and DON'Ts in the science lab:

Laboratory Safety Rules
Before the experiment
1. DO NOT enter the lab without the teacher's permission.
2. Read and understand the experiment fully before carrying out the experiment.
3. Wear safety goggles whenever conducting experiments involving the heating and mixing of harmful chemicals. Also try to minimize the handling of harmful chemicals like carrying it around.
4. NO foods and drinks are allowed in the lab.

During the experiment
1. DO NOT run around and play especially when holding harmful chemicals.
2. DO NOT play with the electric mains and the electric cables.
3. Report any spillage of chemicals or any broken apparatus immediately.
4. Wash your clothes or any part of your body if any chemicals spilled on your clothes.
5. DO NOT taste or smell the chemicals. It might be fatal!
6. When mixing or boiling chemicals in a test tube, always point the mouth away from your friends or you.

After the experiment
1. Dispose of materials and chemicals properly as instructed by the teacher. Do not pour excess chemicals back into its container to prevent contamination.
2. Do not remove chemicals or apparatus from the lab without permission.
3. Wash and clean all apparatus after using and return them to their proper storage
4. Wash hands after experiments, especially after handling chemicals

She also asked us about the Attitudes of a Scientist
A Scientist should have these qualities:

-Curiosity

-Perseverance

-Positive

-Open-minded

-Cooperation

-Patience

After that, we touch on to the symbols of hazards.

These are some basic ones:

 

Now, my favourite part, Drawing of Laboratory Apparatus.

I love drawing but when I draw, the edges of the apparatus is always came out quite fuzzy. Ms Nada said that the apparatus cannot be fuzzy and we have to use a ruler to draw the straight parts of the apparatus. My drawings skills still need more practice~ So I won't show my drawings lah~

We also learnt about How To Light Up a Bunsen  Burner.

Here is a picture of a Bursen Burner.....

 




















And here are the steps to light up a bursen burner:

1. Check the gas tap if it is closed

2. Close the air-hole

3. Put the lighter above the barrel

4. Turn on the gas tap

5. Strike the lighter to ignite the gas

6. Open the air-hole until a non-luminous flame is obtained

 

There are three types of flame:

Luminous flame:

• Produce when the air-hole is close completely

• Insufficient is allow to mix with the gas therefore gas not burn completely

• Orange in colour

• Appear flickering and unsteady

Non-luminous flame:

• Occur when the air-hole is open partially

• Sufficient air is allow to mix with the gas therefore gas is burn completely.

• Blue in colour

• Burn steadily

• Hotter than luminous flame

Strike back:

• Occur when the air-hole is completely open

• There is large supply of air

• Green in colour

• EXTREMELY HOT !!!!!! (That's why close the air-hole is IMPORTANT!)