Explosive Science

Looking back, it was sure a fun time learning science in HC, we learned so much about the science around us and Ms nada was indeed a very good teacher. It is almost a year now. The final year exams are coming and i got to study hard. I would like to thank Ms Nada for her support and her being such strong willed to teach us so many things about science. I would like to qute from Issac Newton( the guy who had an apple to fall on his head and found out GRAVITY) "I had seen further by standing on the shoulders of giants( Ms Nada) " Thank you Ms Nada for teaching me and my class 1P3 : )

Time for a quick history lesson :
In the mid-17th Century, biologist Jan Baptist van Helmat suspected that plant growth had to come from water, after test he conducted showed no change in soil amount. However, carbon rich organic molecules can be found in plants. Water does not provide carbon. Thus, from that point, scientists discovered that water was an important element for photosynthesis, but not the sole component. The process of making food was thus defined as photosynthesis. This was a step for man kind to finding out what was.....
PHOTOSYNTHESIS
It is a process which occurs only during the day. Carbon dioxide is taken in by the stomata, water by the roots and light trapped by chlorophyll to produce glucose and oxygen.


Chloroplast
- disc like structures found in the cytoplasm of a plant cell
- chlorophyll found stacked up in chloroplast
- leaves are green due to chloroplast which reflects green light.
Glucose
- food for the plant
- stored as starch in other parts such as in the root, potato
Stomata
- found mostly on the underside of a leaf to prevent water loss
- has two guard cells at the sides responsible of opening and closing of stomata
- allow gas exchange 


Here are some of the test you can do to find out if the leaf is making food(photosynthesising)

• Carbon dioxide bubbled through Calcium Hydroxide(lime water though now in sec 1 cannot be used), a white precipitate ( milky ) will be formed in the Calcium Hydroxide.

• Oxygen will relight a glowing splint
• Brighter glow is also counted as a presence of oxygen

• A variegated leaf is destarched(no light, kept in a dark room ) for 4 days, before boiled and soaked in ethanol to stop all chemical reaction within the leaf and decolourise it.
• Next, Iodine solution is dropped onto the leaf.
• If the leaf turns brown, Starch is absent.
• If it turns blue- black, Starch is present

Here is a website about the digestive system >> The digestive system

Diffusion and osmosis
Diffusion and osmosis occurs from "more to less"

• Small molecules consist of salt, water and glucose

Large molecules consist of starch, sucrose and urea


Diffusion >>
- a net movement of molecules from a higher concentration to a region of a lower concentration
- concentration is the number of particles
- when both sides are of the same concentration there would be no diffusion
- slow process


Osmosis >>
- occurs only for water
- dilute solution = more concentration of water
- concentrated solution = less concentration of water
- The net movement of water molecules from areas pf higher density to an area of lower concentration through a partially permeable membrane.”

• An Isotonic solution > is one with an equal water to solute concentration
• A Hyptotonic solution > is one with a higher concentration of water than the solution
• A Hypertonic solution > is one with a lower concentration of water than the solution
• 
  
• PLUS
• Animal Cells that have 
• too mush water - lysed
• same amount of water - normal 
• too little water - shrivelled
• 
  
• Plant Cells that have 
• too much water - turgid
• same amount of water - flaccid
• too little water - plasmolysed
• 
  
• 
  

Firstly we learned how to draw the cells of both plant and animal.
here is how we should draw and label :


The hardest part was trying to draw the circle and the rounded edge square without being able to see where we started and end. Ms Nada had a very sharp eyes and could easily see where we started and ended. It took me 5 attempts to be able to draw the perfect one. Practice makes perfect, so remember to keep drawing and drawing...

We also had a chance to scrap our own cheek cells and to see it under the microscope and it was so interesting. we also had to learn how to peel of a thin piece of  skin from the onion and view its plants cell under the microscope.

 is the required drawing of the different diagram.

Solution
- formed when the solute completely dissolve in the solvent
- a solution is homogenous
- it is colourless and nothing should be seen suspended in it
- upon filtering there should be no filtrate 


Suspension
- solute cannot dissolve in solvent
- it is not homogenous
- it is not colourless and there are particles suspended
- upon filtering there is a filtrate




There are also different concentration of a solution >>
>A little amount of solute vs solvent -> dilute solution
>A solution near max solubility -> concentrated solution
>Max solubility -> saturated solution
>Over max solubility -> suspension


Solubility can be effected by :
[ temperature - Kinetic particle theory as when it vibrates faster, more exposed space.
[ size of the particles - more exposed surface area would dissolve faster.
[ stirring - distribution of the particles.

Here is the basics

• An atom is a particle not chemically bonded with other atoms
• A molecule is a cluster of elements chemically bonded togeather
• An element  is a single type of matter
• Compound is multiple types of element chemically bonded togeather
• Mixture is a mix of elements that is not chemically bond.

here are the examples of the different types of element, compound and mixture





Difference between compound and mixture


COMPOUND
> chemically bonded by elements
> separated chemically (exp. heating, electricity ...)
> cannot be separated physically
whereas mixture
> not chemically bonded by elements
> can be separated  physically ( exp. magnet, filtration ....)
> cannot be separated chemically

On Thursday, Ms Nada taught us on how to draw a simple animal and plant cell. Th difficult task was trying to draw a circle without Ms Nada being able to see where the person started from. It was so though that we had to do a lot of practice before we got it right. Also she did not want to see fuzzy lines, too small, too big and lines coming out.
 

Density :
Mass/volume = density
to find density of irregular :
1.weigh the irregular solid to find its mass(M)
2. fill the measuring cylinder 1/3 with water(V1)
3. tie a string to the irregular solid and lower it into the water(V2)
Note : use a sinker if irregular solid floats
4.  The volume of the irregular solid is (V1 - V2)
5. Take the mass and divide by the volume to find the density of the irregular solid.

Kinetic particle theory

The bunsen burner has 5 main parts.
1. Barrel - to raise the flame to a suitable height
2. Collar - to regulate the amount of air entering the air hole
3. Air hole - to allow air to enter
4. Jet - to enable gas to rush out
5. Base - to support the bunsen burner
- Gas Tap -  to control the size of the flame

Types of flames:
Luminous
- orange in colour
- flame flickering and unsteady
- gas not burnt completely
- air holes are closed and very little air is allowed to mix with the gas
- not very hot
- carbon particles are deposited on apparatus


Non-luminous
- blue in colour
-flame burns steadily
- gas burnt completely
- hotter than luminous flame
- hottest part is above the tip at the blue zone
- air holes are open allowing air into the bunsen burner 
(used in the lab for heating)




STRIKE BACK !
> occurs when too much air entering the air hole
> the gas burns at the jet
> turn of gas tap immediately and inform the teacher( do not touch any part of the bunsen burner)


Heating liquid in beaker:
1. put the wire gauze on the tripod stand
2. put the beaker of liquid on the wire gauze
3. light the bunsen burner and push it under the tripod stand

Heating liquid in the test tube:
1. hold test tube with test tube holder
2. ensure mouth of test tube is no pointing at anyone
3. slant the test tube of about 45 degrees
4. heat the test tube by moving it through the hotest part of the flame
5. liquid should be about one third of the test tube

Danger symbols:
This website would show you the danger symbols and what they mean.
Science lab danger symbols!
Apparatus in the lab:
This website shows you all the lab apparatus used
Lab apparatus!

1) Independent variable:
- values that are chosen by the experimenter.
-variables are independent to the participant's behaviour.
- exactly like the experimental group without the experimental treatment.
2)Dependent variables
- value you observe and record in experimental designs
- depends on the behaviour of the participant rather then being set by the experimenter
3)Constant Variable
- scientists attempts to keep constant
- absence of the independent variable.
We also learned how to plot a graph

1.Give the title of the graph
2.Label the axis with name and unit of the quantity
3.Choose the suitable scale that the graph is big. No mutiples should be used.
4.Mark the values on each axis at a regular intervals
5.Mark each point with a small cross.
P.S.( SHARP PENCIL SHOULD BE USED )

on our first day in school in term one, Ms nada started teaching us on lab safety. First the do and don'ts in the lab.
DO
-Always follow the teachers instructions
-Keep note books and paper away from the bunsen burner flame and other chemicals.
-Tell teacher upon sustaining any wounds during experiments.
-Report to teacher of any broken glassware or spilled chemicals.
-Wait for heated equippment to cool down.
-Leave all benches and table clean and dry before leaving.
-Wash hands after experiments.
-Point test tube away from your's or anyone's eyes.
-Wear safety googles at all times.
Don'ts
-Enter labortary without teacher.
-Play or behave roughly.
-Eat or drink in the laboratory.
-Smell or taste substances.
-Put solid objects into the sink.
-Pour substances down the sink.
-Mix chemicals without teachers instructions.
-Look directly on top of test tube, beaker or flask.

As the start of Term 3 there are a few things to begin with...
1. List of elements Al, Zu, Cu, Mg, Hg, Fe, C, S, Cl, N, I, H and O ( list 20 elements inclusive )
2. E-portfolio : Deadline End of Term 3
3. Ace : Deadline T3W6 Fri 23:59
4. Term 3 Test wk 6 Thu 4/8

On: Element, compound, mixture,                          15 MCQ
solution, suspension, separation technique             25 structured questions
                                                                              -------------------------------
                                                                               40 marks and 5 marks for pop quiz S.I.units

5. Topics to be taught in Term 3
- cell
- diffusion and osmosis
- digestion
- respiration
- photosynthesis

Practical : D
-- Wk 2, 4, 6, 8