Intro

Hi I am Dave Zhang 1P333. This is my Science E-portfolio, I have put in my effort, there are videos pictures and useful information, sit back and relax!!

SI units

temperature-Kelvin K
time-second s
length-metre M
electric current-ampere A
mass-kilogram kg
intensity of light-candela cd
amount of substance-mole mol

Giga	One billion 1000 000 000	G	1 Gm = 1 gigametre = 1000 000 000 metres
Mega	One million 1000 000	M	1 Ms = 1 megasecond = 1000 000 seconds
Kilo	One thousand 1000	k	1 kg = 1 kilogram = 1000 grams
Deci	One tenth 1/10	d	1 dg = 1 decigram = 1/10 grams
Centi	One hundredth 1/100	c	1 cm = 1 centimetre = 1/100
Milli	One thousandth 1/1000	m	1 ml = 1 millilitre = 1/1000 litres
Micro	One millionth 1/1000 000	µ	1µl = 1 microlitre = 1/1000 000 litres
Nano	One billionth 1/1000 000 000	n	1ns = 1 nanosecond = 1/1000 000 000 seconds

Vernier calipers

Inside jaws- used to measure the internal diameter of an object
Outside jaws- used to measure the external diameter or width of an object
Main scale- gives measurements of up to one decimal place
Vernier scale- gives measurements of up to  two decimal places
Tail-used to measure the depth of an object or hole

Drawing of Laboratory Apparatus

These are some of my drawings

Symbols for safety precaution

	Radiation	These substances are radioactive. Radiation can damage cells and cause cancer.
	Biohazard	These are living organisms that may cause infection.
	Explosive	A substance that may explode if it comes into contact with a flame or heat. It may also explode due to friction or shock.
	Oxidising	This type of substance gives of a large amount of heat when in contact with other substances.
	Toxic	A substance that is poisonous if swallowed or breathed in. It may even go through your skin!
	Corrosive	A substance that may destroy living tissue on contact.  It causes a burn.
	Flammable	A substance that can catch fire easily.
	Harmful	A substance that may cause harm in some way
	Irritant	A substance that may cause irritation to the skin, eyes or inside your body.

LAB Safety

BEFORE THE EXPERIMENT

• do not enter the laboratory to conduct experiments without your teachers permission
•  read and understand instructions on how to carry out an experiment
• if you are unclear please clarify with the teacher
• wear safety goggles whenever you or your friends around are conducting experiments that involve heating and mixing of harmful chemicals.
•  check the label of the container that matches what you have to use and remember to close it properly after use
• if you have long hair or long sleeves please tie or roll them up to avoid them getting caught in an open flame or chemical spillage
• Do not bring food or drinks into the laboratory
• no eating or drinking is allowed during laboratory sessions

 DURING THE EXPERIMENT

• do not run in a laboratory, especially when you are carrying chemicals or laboratory apparatus
• do not insert wires, metal strips or sharp objects into electrical mains nor tamper with electric cables
• if you see any exposed electrical wires, report to your teacher immediately
• report any accident such as spillage of chemicals or broken apparatus to you teacher
• wash you clothes or any part of your body thoroughly with water immediately if any chemical spills on your clothes
• do not taste any chemicals in the laboratory, as some may be highly corrosive or poisonous
• when mixing chemicals or boiling liquids in a test tube, always point the mouth of the test tube away from anyone close to you, so as to prevent any injury caused by chemical reaction or boiling liquid
• do not leave any highly flammable substances near any naked flame
• follow instructions of experiments closely to ensure that you are handling chemicals and apparatus correctly

AFTER THE EXPERIMENT

• dispose of materials and chemicals properly as instructed by teacher
• pour away any excess chemicals back into their containers or sink
• do not remove any chemical or apparatus from the laboratory without permission
• wash, clean and tidy up all apparatus after each and every experiment
• return them to their proper storage area after washing
• wash your hands after each experiment, especially when you handle chemicals 

Skills and Attitudes to Science

Creativity

• A creative person will seek innovative and relevant ways to solve problems and particularly challenging ones.
• An example is that even before Wilbur and Orville Wright had invented airplanes, scientists went into creative pursuit such as studying of mechanical flight by Leonardo da Vinci to designs of gliders by Sir George Cayley, the Father of  Aerodynamics 

Curiosity

• A good scientist is always curious about how and why things happen around them, near or far. When there is questions, it will lead people to make observations and thus gain new understanding of the environment, and they might also go explore deeper thus having more new findings.

Objectivity 

• You must never let your belief or first impression prejudice the influence the way and experiment is conducted, analyzed or reported.  

Open-Mindedness

• It is very important for you to be flexible and be willing to change your views if the evidence is convincing. This is very important especially when you work as a team with many members, and all of them might have different views from each other.  

Perseverance

• It is to pursue a problem until a satis factory solution is found even when initial results may not be what you expect. As every failed experiment is an opportunity to learn.
• An example is that, Thomas Edison the inventor of the light bulb, had tried 3000 metals that did not work for a filament before he found one that could work. And some more he made EIGHT THOUSAND AND ONE attempts to find the right material that can hold an electric charge in a battery.
• Another example is that Albert einstein probably had Aspergers Syndrome, a type of autism widely stated that he was dyslexic ,but there is some controversy about this. But he overcomed difficulties and he was a brilliant atomic physicist, probably most famous for his Theory of Relativity. 

Bunsen Burners

Non-luminous flame

•  when the air hole of the Bunsen Burner is open 
• when the air hole is open, more oxygen can enter the burner; therefore, hotter flame will be produced." 
• its color is transparent or blue 
• Blue flames are its hottest flames 

Luminous flame

•  is produced when the air hole is closed
• if the air hole is closed, oxygen cannot enter the burner; therefore, least hotter because the combustion is not fully complete with least oxygen 
• A luminous flame has an outer of orange color and an inner of blue. 
• Luminous flames emits more light than non-luminous flames.
  

Term 3 Ace

Observations before

The potato in the Salt water solution

                               i.            The slice of the potato was floating near the surface of the water

                             ii.            Its diameter is 4.2 cm

The potato in the Sugar water solution

                               i.            The slice of the potato floated in the middle of the cup

                             ii.            The diameter of the potato is 4.2 cm

The potato in the Plain water

                               i.            The slice of the potato was at the bottom of the cup

                             ii.            The diameter of the potato is 4.2 cm

Observations after an hour

The potato in the Salt water solution

                               i.            After an hour, there were air bubbles form on the surface of the water

                             ii.            The slice of potato sank to the bottom of the cup after an hour

                          iii.            The slice of the potato had turned a little darker

                          iv.            The size of the potato has decreased it shrank by 0.3 cm

                             v.            It turned more flexible and soft

The potato in the Sugar water solution

                               i.            The potato sank to the bottom of the cup after an hour

                             ii.             The potato turned smaller a little

                          iii.            It also became a little softer but not as much as the on in the Salt water solution

                          iv.            The size of the potato remained the same, as it is still 4.2 cm.

The potato in the Plain water

                               i.            The potato remained at the same place it did not sink or float

                             ii.            It turned larger by 0.2cm

                          iii.            It became more rigid than it was at the start

 

	The potato in the Salt water solution	The potato in the Sugar water solution	The potato in the Plain water
BEFORE AFTER	4.2 cm 3.9 cm	4.2 cm 4.2 cm	4.2 cm 4.4 cm

Why did that happen? It has to do with a process called osmosis. The potato is made up of tiny, living units called cells. Each cell is surrounded by a cell membrane which acts much as your skin does. It keeps the cells parts inside and keep other things outside, protecting the cell. While this membrane stops most things, water can pass through it. The water tends to move towards higher concentrations of dissolved chemicals. That means that if the water outside the cell is saltier than the water inside, water will move from the inside of the cell to the outside. That is what happened to the slice of potato in the salt water. As the water left the cell it was much like letting the air out of a balloon. As more and more of the cells lost water, the slice of potato became soft and flexible. The same thing happened for the sugar, but since the cells in the potato contain more sugar than they do salt, the cells did not get as soft.

When you put the potato into the plain water, the reverse happened. Water moved from the outside, where there was no salt or sugar, into the cell where there was some. This caused the cells to swell up, becoming very stiff.