Lesson learnt on separation techniques

Separation Techniques
-magnetic attraction
-filtration
-evaporation to dryness
-crystillation
-distillation
-chromatography
-sublimation

The physical methods used will actually depend on the nature of the constituents.

Separating Funnel
-for 2 immiscible liquids
-ex:oil and water

Filtration
-for insoluable solids with liquids( suspension )
-the insoluable solids that remain on the filter paper are called residue,whereas the liquids that pass through the filter paper are called filtrate
-Ex: air filters in air conditioners to remove solid impurities from the air
hair in our nostrils to trap dust in the air

Evaporation to dryness
-Ex: obtaining salt from seawater

Distillation
-to separate a solvent from a solid-liquid solution or liquid-liquid solution.
-pure water can be distilled from soft drinks

Fractional distillation
-used to separate miscible liquids with different boiling points.
-the liquid with lower boiling points will vapourise first
Ex: alcohol and water

Chromatography
-to separate the different components in a liquid orgaseous mixture
-Ex:used to separate the different coloured components that make up black ink
-happens because some components of the liquid mixture travels at a faster pace than other components on the paper or any absorbent material
-the mixture is separated as the solvent travels up the paper
-a chromatogram of the separated components is obtained
-advantage: able to obtain the results quickly
only a small concentrated amount of sample is required for chromatography

Reflections
After learning all the separating techniques and gone through all the experiments, I had discovered more separating techniques as compared to primary school. I had also knew the steps to carry out the methods.
These separating techniques is very useful , especially in surviving skills. For example, we can obtained pure water to drink from muddy water through filtration.

Lesson learnt on solute,solvent,suspension and solution

Solute is a substance which dissolves in a liquid.

Solvent is a liquid which dissolves other substances.

Solution is when a solute dissolves in a solvent.It is a homogeneous mixture in which one or more substances are dissolved in another substance.

Remember, solute + solvent = solution!!

Question : 30 cm ( cube ) + 50 cm (cube ) equals to 80 cm ( cube )?

False!!!!!!!

That is not true as the solute particles are smaller then the solvent particles, therefore the solute particles will occupy the space between the solvent.

When a solute dissolves in a solvent, the solute particles surround each solvent particles. The particles then mix uniformly to form the solution. They do not combine chemically.

Types of solution

solid-liquid: sugar solution, salt solution

gas-liquid:hydrochloric acid, soft drinks

solid-solid:brass, bronze

liquid-liquid:vinegar, beer, wine

gas-gas:air,natural gas

Suspension

-suspension is a mixture of small insoluable particles in a liquid gas.

-when a solid does not dissolve in a liquid, a suspension is formed.

-the solid is said to be insoluable

Ex of suspension: calamine lotion, medicine, sea water

Question: Why does suspension formed?

Ans: In a suspension, the solvent particles are smaller, whereas the solute particles are bigger, therefore they don't formed a solution.

Question:Why does suspension appears cloudy or chalky?

Ans: It's because some particles are so light that they do not sink but remain floating.

As the solid particles are bigger than the liquid particles and the holes in the filter paper, suspension can therefore be separated by filtration.

A saturated solution contains the maximum amount of solute that can dissolved in a fixed amount of solvent at a particular temperature.

Solubility of solutes

-the maximum amount of solute that can dissolved in 100g of solvent at a given temperature.

-higher the solubility, the more soluble the substance.

Strength of a solution=concentration

The concentration of a solution=the amount of solute in 1000cm ( cube ) of solution.

A concentrated solution can be made more diluted by adding more solvent.

Ex: to dilute a cup of orange juice, we can add more water

Factors affecting the extent of dissolving

-Nature of a solvent

The solubility of a solute is different in different solvents.

-Nature of solute

Different solutes have different solubility in a solvent.

-Temperature

The higher the temperature of solvent, the higher the solubility of solute.

Rate of dissolving is affected by

-Temperature

-Rate of stirring

-Size of solute particles

Reflections

After learning all these, I had more understanding of liquids and solids particles and they can even help me in my daily life.

Foe example, when I'm about to be late for school, I would prepared a cup of milo with high temperature of the water and also stir as fast as possible, so that the solute particles will dissolved faster and I will not be late.

I could also used this concept when making a cup of orange juice or even Ribena. I learnt how to make the juice more diluted or concentrated according to the guest.

Lesson learnt on element,compound

Elements are substances that cannot be broken down into simpler substances by chemical methods.

The different elements in a compound always join together in a fixed proportion by mass.

However, compounds are substances that could be broken down but it can only be broken down by chemical methods.

All the elements can be found in the Periodic Table. The columns of the Periodic Table are called group whereas the rows are called period.

Name of the element Symbol of the element

Aluminium Al

Zinc Zn

Copper Cu

Magnesium Mg

Mercury Hg

Iron Fe

Carbon C

Sulfur S

Chlorine Cl

Nitrogen N

Iodine I

Hydrogen H

Oxygen O

For those that were highlighted in red, they need a " 2 " below them when the questions did not mention the word element.

Elements are broken down into metals and non-metals.

Metals:Aluminium,calcium,copper,mercury,iron,zinc

Non-metals: Oxygen, hydrogen,helium,iodine,sulfur

Differences between metallic element and non-metallic element

Metallic element Non-metallic element

High melting point Low melting point

High boiling point Low boiling point

Good heat conductor Poor heat conductor

Good electrical conductor Poor electrical conductor

Ductile,malleable Brittle

High densities Low densities

Sonorous Not sonorous

Uses of some elements

Carbon

-exists in diamond,graphite,soot,charcoal

Diamond

-hardest

-attached to drills or saws for cutting concrete and drilling into rocks

Nitrogen

-unreactive element

-used in packaging of food

-used to make fertilisers

Sulfur

-non-metallic, yellow

-used to harden rubber used for making tyres

-used in pesticides and drugs

Iodine

-non-metallic

-sublimes when heated to form a violet vapour

-forms tincture of iodine as an antiseptic when dissolved in ethanol

Zinc

-coat iron sheet to make galvanised iron

-mixed with copper to form alloy, brass

Mercury

-the only metallic element that is a liquid at room temperature

-used in thermometers, fluorescent lamps and some dental fillings

Magnesium

-used to make fireworks

Reflections

Because of all these lessons I learnt, I could then be more aware of the elements around me and their uses. For example, if I ever had the chance to see magnesium, I would be more cautious and it was used to make fireworks and thus flammable.

I could also applied this to my daily life and after learning these concept, I could be more aware of the surroundings and the different types of elements.

Self reflection

I think back about my lessons on Science and thought to myself: Have I really learnt and gained some knowledge?Can I list out knowledge that I learnt,without looking at my notes?

The answer?Some yes and some no.

I reflect deeply,and realise that I had indeed learnt some very useful knowledge, such as knowing more about my body tissues, and also the fact that we should not put plants in our bedroom at night.This is because they will compete with us for oxygen at night when the plants are not making food.

However,I think that instead of copying notes and learning the notes or by blogging, I should also take the initiative to read through the notes clearly and ask myself questions,such as why would this happen?

I could then asked teacher about my questions and maybe shared with everyone.This way, I would not only learnt blindly, but learnt with understanding.

Readings

A ruler's reading is to 0.1 cm
A vernier calipers's reading is up to 0.01cm
A micrometer's reading is also up to 0.01cm

On the vernier calipers, the reading on the top will be called the main scale, while the one at the bottom will be called vernier scale.
When we count the reading on the main scale,we will round it off to 1 decimal point.When we count the reading on the vernier scale,we round it off to 2 decimal points.

On the micrometer,the left is called sleeve while the right is called thimble.

When there's an X positive zero error, we minus X from the observed reading and vice versa.

Measurements
micro = 1 millionth
milli = 1 thousandth
centi = 1 hundredth
deci = 1 tenth
kilo = 1 thousand
mega = 1 million

1cm = 10 mm
1m = 1oocm
1 km to the power of 3 = 1000 000 000 m to the power of three
1 cm to the power of 3 = o.ooooo1m to the power of 3
1mm to the power of 3 = 0.000000001 m to the power of 3

Volume of a cube = L to the power of 3
Volume of a rectangular block = L x B x H
Volume of a sphere = 4
---- pie x radius x radius
Volume of a cylinder = pie x radius x radius x height

SI

SI stands for System International of Units

Acceleration: change of speed
----------------
time

Units of acceleration: m/s
----
s

= m
-- divide by s
s

= m 1
-- times -----
s s

=m/s to the power of 2

SI unit of density = kg
---
m to the power of 3
=kg/m to the power of 3

Reflections
After learning all the readings, I find it useful especially when I need it in the future in Maths.This is also useful if my jod were to involve calculationand measuring.Through the experiment, I had also experience and know how to use the different types of instruments.

Graph

Graph- x axis vs y axis

Important Notes
-against = VS
-always include the units,eg: .../min , .../km
-x represent the value
-every graph must have a TITLE
-TITLE must be underlined
-must be drawn in pencil

Eg: Plot a graph of the speed of the different cars against the time taken by the cars to reach the finishing point

X axis (vertical) : speed of the different cars
Y axis ( horizontal) : time taken by the cars to reach finishing point

Preparation for EOY

After much thought,I decided to blog on the few main points and topics to take note of in Term 1 and Term 2 so as to get myself ready for the EOY Science examination.

Self reflection

After 3 term of lower secondary science lessons,I found out that I had learnt much and also attend some valuable classes.I had also clear my doubts and through all the science lessons and experiment,I had gained alot of knowledge.Especially the experiment, which was done and experienced by myself and thus, the lessons learnt will have a deeper impression on me.The teacher had also clear my doubts with some detailed answers.


I have received my Term 3 Science test and I had improved slightly abit.
Even though the marks improved just by 0.5 to 1 mark,I think it's still a good sign.
I found out that I had improved due to
-copying of notes in class and revise when I went home
-blogging what I have learnt so as to give me a deeper impression

The method is very effective and I think that I shall continue this method so as to achieve better grades in the future.

Lesson learnt on 16 August

Today,we started on a new topic called:Respiration

Respiration is the process by which food molecules are broken down to release energy.It occurs in all cells.

Respiration can be broken down to Aerobic Respiration, which can be broken down to Tissue Respiation and External Respiration.

Aerobic respiration is the process where food substances are broken down in the presence of oxygen, and energy is released in living cells.

The Aerobic Respiration can be summarised by the following equation:
Glucose+oxygen ----------->Carbon Dioxide+water+energy

Tissue Respiration is the process whereby food substances are broken down in living cells.Large amount of energy is released for the cells.

External Respiration is the bringing of the oxygen from the surrounding environment to the cells for tissue respiration to happen.

It helps to remove carbon dioxide and the water formed during tissue respiration from the body.

Breathing is also part of external respiration.

Breathing
-Movements that bring about exchange of gases between body and its surroundings.
-Movements that brings air into and out of the body.
-Air that we breathe in is called inhaled air whereas air that we breathe out is called exhaled air.

Inhaled air Exhaled air
-Contains 21% oxygen -Contains 16% oxygen
-Contains 0.03% of carbon dioxide -Contains about 4% of carbon dioxide
-Contains less water vapour -Contains more water vapour


Breathe in Breathe out
-Diaphragm contracts and flattens -Diaphragm relaxes and arches up
-Rib muscles contract -Rib muscles relax
-Ribcage expands and moves up -Ribcage contracts and moves down

Reflection
After learning more about respiration and also breathing, I knew more about the surrounding air and particularly my breathing.I had also know more about the different types of breathing and respiration too.
These knowledge is useful as I know more about the different components needed for the processes to happen, example water. Thus, i will make sure I drink ample water to allow respiration to happen.

Lesson learnt on 26 and 27 July

On 26 July,we learnt about a new topic called Photosynthesis.

Photosynthesis is a biochemical process in which plants,algae and some bacteria harness the energy of light to produce food.

An important role of Photosynthesis is production.Carbohydrates are formed during Photosynthesis.From carbonhydrates,fats and proteins are formed in plants.

The word equation of Photosynthesis is as follows:

Carbon Dioxide + water ---chlorophyll and light energy----> Glucose + Oxygen

Conditions for Photosynthesis:
-Presence of sunlight
-Presence of Carbon Dioxide
-Presence of chlorophyll
-Temperature
-Water

A variegated leaf is a leaf that is partially green and partially without chlorophyll.It's used to investigate the importance of chlorophyll in starch formation.

Photosynthesis help to purify the air by restoring the level of oxygen and carbon dioxide in the air.

On 27 July,we did an experiment to find out the presense of starch in the leafs and go through some practical as well.

Reflections
After learning the topic Photosynthesis, I had learnt more about the requirements needed for photosynthesis to happen. Thus I will be more aware when I grow plants so as to let them receive sunlight,water to ensure photosynthesis to happen for them to survive.
After I learnt the gaseous exchange in photosynthesis, I could also apply this and put the plant in my room when there is sunlight. This way, my room will become fresher.

Lesson learnt on 20 July

Today,our class had a quiz on the topic "Cells,tissues.organs and systems".

Some of the facts that I learnt after the quiz:
-Supporting tissue found in the plant help to support and strengthen a plant.
-Excretion removes waste material from living cell.
That's all ^^

Lesson learnt on 19 July

Today, we learnt about organs and organ system.Organs are structures made up of different tissues working together for a a specific function whereas organ system consists of several organs working together to perform a special function ex:the digestive system.

Organs of Plant
-Leaf
An organ of photosynthesis (contains photosynthetic tissues)
-Stem
Contain xylem and phloem tissues and supporting tissues.
Provide support and transport food to other parts of the plants.
-Roots
Xylem tissues take in the nutrients from the roots and transport them to other parts of the plant.
Serve to anchor the plants to the soil and absorb water and dissolved minerals.

Organs of Animal
-Stomach
Contains glandular tissues which secrete digestive juices to digest food.
Contains muscle tissues which causes stomach to contract and relax and mix the food well with the digestive juices.
Contains connective juices which helps to connect other tissues.
-Heart
Circulates blood around the body.
Consist of blood tissue.
Contains muscle tissue which causes heart to contract and expand to circulate blood.
Contains connective tissues which helps to connect the other tissues.

Organ system in animals
-Respiratory system
Consists of lungs,windpipe and mouth.
Supplies the body with oxygen and remove carbon dioxide.
Allows animal to breathe in order to carry out respiration.
-Digestive system
Breaks down food into smaller and soluble substances that can be absorbed by the blood.
-Circulatory system
Made up of heart,capillaries,arteries and veins.
Aloows animal to circulate blood around the body so that different parts of the body will receive food,oxygen.

Lesson learnt on 13 july

Today we went to the lab and did an interesting experiment.We experiment with our cheek cells and also the onion cells and even had the chance to use the microscope ourselves!!!it's enriching and we had a fun time too.

After the experiment,Mrs Chu continued to teach the topic where she left yesterday.

Connective Tissues are divided into 4 main groups which are as follows :

Dense Tissue forms ligaments and tendons.It's densely packed and have great tensile strength.

Loose Tissue helps to hold organs in place.

Reticular Tissue is a network of reticular fibers ( fine collagen ) that forms a soft skeleton to support the lymphoid organs ( lymph nodes,bone marrow and spleen ).

Adipose Tissue is used for cushioning,thermal insulation and energy storage.



Nerve Tissue is to make up the nervous system that carry information within the body.

Glandular Tissue forms gland that produces substances to secrete hormones and sweat.

Lesson learnt on 12 july

Yesterday,our teacher started on a new topic which we are familiar with-
Cells,Tissues,Organs and Systems
As everyone knows,cells are the smallest unit of life.
There are animal cells and plant cells in animal and plant respectively.

Similarities between animal and plant cells
-Both have nucleus,cell membrane and cytoplasm.
Differences between animal and plant cells
-Animal cells have small and numerous vacuoles while plant cells only have one big vacuole.
-Animal cell's vacuoles contain air,food and water,whereas plants cell's vacuole has sugar and salt.
-Plant's cell contains chloroplasts but not animal's cells.
-Plant's cell contains cell wall but not animal's cells.

Many cells form Tissue.
Many Tissue form Organ.
Many Organ form Organ System.
Many Organ System form a Organism.

In plants,the tissue found are:
Epidermal Tissue ( known as Epidermis as well )
Xylem Tissue
Phloem Tissue
Photosynthesis Tissue ( known as mesophyll as well )
Palisade Tissue
Epidermal Tissue protects the underlying cells of a leaf by preventing water loss and acts as a barrier to fungi and other invaderes.

Xylem Tissue transports water and dissolved mineral salts to the leaf.

Phloem Tissue transports the manufactured food away from the leaf to other parts of the plant.

Photosynthesis Tissue carries out photosynthesis.

Palisade Mesophyll Tissue are long cylindrical cells that occur at right angle to the epidermis.It contains numerous chloroplasts for photosynthesis.

In animals,the tissues found are :
Epithelial Tissue ( known as Epithelium )
Muscle Tissue
Connective Tissue
Nerves Tissue
Glandular Tissue

Epithelial Tissue covers the internal and external surfaces of an organ.It lines both the outside ( skin ) and the inside cavities of an animal.Its functions include secretion,absorption,protections,trancellular transport,sense of touch.

Muscle Tissue is divided into three main groups :
-Smooth Muscle Tissue
It's from hollow organs such as stomach etc.Its function is the propulsion of substances along internal passageways.
-Skeletal Muscle Tissue
It's from skeletal muscle.Its function is the contraction for voluntary movements.
-Cardiac Muscle
It's found along the walls of the heart.It pumps blood in the circulatory system.

Reflections
After learning all these, I am more aware aboiut my body system and organs. I also learnt more about the functions of the organs and system. This will come in handy when some part of my body is not working, example the epithelial tissue, and I will know it as the function is not present.

Term 3

Term 3 had already started and I had plans for this term.

-From now onwards,I'm planning to blog about what I learnt after every lesson.
-Through this way,I can remember the facts better and it also serves as a form of revision for me when I get home.
-I also want to clear my doubts as possible so as to achieve my best for Term 3 test.
-Not only that,I will also spent some of my time to teach and guide those that are weak in their Science so that the whole class'MSG will improve as a level.

Term 2

Term 2 is about to be over and unfortunately,my science grades have dropped from Term 1.However,I think it's still a good grade.I think in order to prepare myself for the term 3 test,I should revise my mistakes in Term 1 test and Term 2 test.I will also take out my free time to read the notes and powerpoint slides attached online.I will try my very best and strive for good grades in Term 3.

Field trip reflections

Reflections

Through this field trip, I learnt of many science-related things and interesting facts, which I'm not able to learn in class. It is really an eye-opener for me as there are a lot of experiment structures and also cool images depicting and further describing the complicated information. Some of the topics that is included in the Science centre are “Human Body” , “DNA Lab” , “Brain Station” , “Living with viruses” , “Climate change” , “Sound exhibition” , “The Mind’s eye” and many more. I am also surprised by the wide variety of topics and information that they covered, especially their creative and cool experiments, like eye illusions etc.

At first, I had problem finding which topic should I look up on for my Science Ace, as there are simply too many topics in Science Centre. I then made the decision to look up on topics that my Primary School had covered. It's because the topics taught in Primary School might not be taught in Secondary School and I wanted to recap the topics learnt in Primary School. Since some of the topics are also about to be taught in Secondary School, I may just want to have a brief look at them and not include them in my Science Ace assignment.

After gathering the information, I then worked on it and put it into different graphs and diagrams. The whole process is fun and I really experience the true meaning of independent studies through this assignment. It is also challenging when I research on those five questions. Overall, I loved the whole process of the field trip and also typing and sorting out the information.

Plans for Term 2 test

In term 2 test, there will be alot of topics tested and also harder. Thus, I will make full use of my free time to revise my science notes and also ask teacher if I had any queries.I know that I am very weak in my conversions, therefore I will practice more too to make sure that I am sure of that skill before the test.

I will also pay more attention in class and be less distracted by my peers.This will allowed me to be more focused and on task,which is very essential for good grades.Last but not least,I will also hand in my assignments punctually and the teacher can thus return me the assignments on time for me to revise.

Lesson learnt in Term 1

After Term 1, I found out that I had learnt a lot of stuff.I have learnt:
-the laboratory rules
- the purpose of all the science apparatus and how to draw the outline of them
-the luminous and non-luminous flame (the similarities and differences)
-how to measure vernier calipers and micrometer screw guage

Feedback after Term 1:
I think that the teacher is quite clear and at the correct pace for me to understand fully the science topic.I have learnt well under her teaching and guidance.She also does not hesitate to clear the students'doubts when we ask her questions.But,I think that the time for us to do experiments is too short and we do not have time to really observe the results.However,it's still a good and enjoyable learning experience for me.

Term 1 test results

My first class test results is out and fortunately, I got an A1. However, it was a really low A1 and thus, I decided to work harder for my second class test. I am rather weak at the science laboratory apparatus, and I am going to work harder at it. Other than that, I am also quite weak at the steps of an experiment, as I aways could not remember them clearly which step comes after which. Overall, I had alot to buck up on my second test and I hope to get a better result.

My self-Introduction

Hi Ms Chu and classmates, I am Sheng Xiang from 1P4.For those that wanted to contact me,my email is louise_per@hotmail.com.Basically, you can just call me louise.As for the brief description about myself,I really did not have much to say about.I am a very direct person and I like things to be done neatly.During my leisure time,
I will read some books or even play some outdoor sports.I am sporty and just can't sit still.I hate irritating people and smart alec ones.

My favourite food is just noodles and rice.I drink almost everything drink.My favourite colour is green as it let me feels refreshing. In my primary school, I was not very good with my science so I hope I can get guidance from my friends and teacher. To me, science is actually fun if the lesson includes interesting experiments. Some of the science facts are also very interesting and fascinating which make me want to go and find out more. I hope that in my Sec 1 Science lesson, it can be fun and interesting as i had expected it to be.
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