Term 3 reflections/notes

In this term, we were taught the drawing of plant cells and animal cells, photosynthesis, transport in living things, the digestive system and respiration.

Cells
In this topic, we were taught the differences between a typical plant cell and an animal cell. Also, we were taught how to draw the cells. This was of some difficulty as we were not allowed to use rulers to draw the plant cell and it was difficult to draw a 'perfect' circular cell membrane of an animal cell.

Plant Cell:



Animal Cell:



Transport in Living things
The transport in living things are due to two processes: Diffusion and Osmosis.
Diffusion is the net movement of particles from a region where they are at a higher concentration to that of a lower concentration. It is the basis of the exchange of oxygen and carbon dioxide taking place in the lung's air sacs.

Term 2

In Term 2, we were taught S.I units and prefixes, the apparatus used to measure them with, how to find the density of irregular objects and the kinetic particle theory. The topics in this term taught were Elements, Compounds and Mixtures, Solutions and Suspensions, Separation Techniques and Cells.

S.I Units:

1. Temperature=Kelvin(K)
2. Time=second(s)
3. Length=metre(M)
4. Electric currents=ampere(A)
5. Mass=kilogram(kg)
6. Amount of substance=mole(mol)
7. Intensity of light=candela(cd)

Measurement: Vernier Calipers

1. Close the jaws and check for the zero error. To prevent zero errors, ensure that the zero marks on the main and vernier scales coincide.

2. Clamp the jaws on the object to measure the external length

3.Record the reading on the main scale

4. Record the reading on the vernier scale for the division which coincides with the main scale division to straight line

5.The actual measurement will be taken by adding both readings together

(Note: If the zero of the vernier scale is to the right of the zero of the main scale, a positive zero error is present in the instrument. If the zero of the vernier scale scale is to the left of the zero of the main scale, a negative zero error is present in the instrument. Thus, to get the correct length of the object, the zero error has to be added or subtracted from the recorded value.)

Elements: The Periodic Table

Term 1 Reflections/Notes

In Term 1, we were introduced to the apparatus in the laboratory, laboratory safety rules and how to use the Bunsen burner. We were also taught the skills and attitudes of a scientist and other skills such as drawing a graph.


Laboratory safety rules (Do's and Don'ts):


Do


Always follow your teacher's instructions carefully


Keep your writing materials away from heating equipment, glassware, chemicals and flames

Tell your teacher immediately when you are cut or burn in the laboratory


Report to the teacher immediately if you break any glassware or spill any chemicals. Spillages, even if water, need to be cleaned up without delay


Wait until hot equipment has had time to cool before putting it away


Leave all benches and tables clean and dry when you have completed an experiment


Wash your hands after handling any substances in the laboratory


Tie long hair back if you see a Bunsen Burner


Point test tubes away from your eyes and your fellow students'


Wear safety goggles when heating or mixing substances


Follow your teacher's directions about the disposal of substances




Don't


Enter the laboratory without your teacher's permission


Run, push or behave roughly in the laboratory


Eat or drink in laboratory


Smell or taste substances unless instructed by your teacher.When you do need to smell  substances, fan the odour to your nose with your hand


Put solid objects such as matchsticks and pieces of paper in the sink


Pour substances down the sink


Mix chemicals without instructions given by your teacher look directly above the test tube, beaker or flask


Enter a preparation room without your teacher's permission


Bunsen Burner


Next, Ms Nada introduced us to the Bunsen Burner. We were warned about the dangers of a strike-back, how it looked like and what to do in such an occasion. We were also taught about the different flames from a Bunsen burner: the Luminous flame and the Non-Luminous flame. 

















On the picture above, 1 is a luminous flame and 4 is a non-luminous flame. The picture below describes the colours of the different regions in the flames.

The Attitudes of Scientists


A scientist should have creativity, curiosity, objectivity, open-mindedness, integrity and perseverance. A scientist should be able to share his discoveries and ideas to fellow scientists, so that all can make a faster and better journey to reach the common goal. A scientist must have creativity for ideas to flow. A scientist must also have integrity and be transparent and must have a vision to bettering the lives of humankind, not for destructive purposes.


Drawing of a Graph


Lines in graphs for science, are either straight or curved. The first step in drawing a graph is marking points on the graph based on data collected. Then, decide whether the line should be drawn straight or curved. If the points on the graph seem to be in a trend, but has a few points out of it, we use a best-fit line. Below is an example:





A wrong example:

If the lines on the graph form a certain curve, then without the use of rulers, draw a curved line.

• • This is a summary of graph drawing in science 

How To Construct a Line Graph On Paper
Step	What To Do	How To Do It
1	Identify the variables	Independent Variable - (controlled by the experimentor) Goes on the X axis (horizontal) Should be on the left side of a data table. Dependent Variable - (changes with the independent variable) Goes on the Y axis (vertical) Should be on the right side of a data table.
2	Determine the variable range.	Subtract the lowest data value from the highest data value. Do each variable separately.
3	Determine the scale of the graph.	Determine a scale, (the numerical value for each square), that best fits the range of each variable. Spread the graph to use MOST of the available space.
4	Number and label each axis.	This tells what data the lines on your graph represent.
5	Plot the data points.	Plot each data value on the graph with a dot. You can put the data number by the dot, if it does not clutter your graph.
6	Draw the graph.	Draw a curve or a line that best fits the data points. Most graphs of experimental data are not drawn as "connect-the-dots".
7	Title the graph.	Your title should clearly tell what the graph is about. If your graph has more than one set of data, provide a "key" to identify the different lines.

Source: http://staff.tuhsd.k12.az.us/gfoster/standard/bgraph.htm

How to Draw Apparatus

Note: 

1. When during a straight line of an apparatus, use a ruler

2. When drawing more than 1 apparatus together, make sure the size is in proportion (example: a Bunsen burner should not be drawn larger than a retord stand.

Science Eureka Journey 2011 Term 2 (Day 4)

Day 4, we conducted the following experiments:

1. Confounding Colour
2. Colour the Metal
3. Technicolor cloth

Science Eureka Journey 2011 Term 2 (Day 3)

On Day 3, we carried out the following experiments:
1. Mechanics: Balloon Track!
2. The Strongest Bridge
3. Light Angles: Using Water to Refract Light
4. Suspended Animation (Mass, weight and density)


Experiment 1 was about mechanics. Using simple materials such as balloons, strings and drinking straw, taped together, a fascinating feat is performed. Using a string as a "track", the balloon is made to move along it just by air power. Then, after learning the basics, we competed to build the best "rocket" that was able to travel the greatest distance. This experiment taught us how kinetic energy of the air could allow movement of objects.


Experiment 2 was building a bridge using ice cream sticks. It allowed us to compete between groups to build the strongest bridge. It was tested by hanging weights onto the bridge and noting them. This experiment tested us on both creativity and logical thinking. We figured out that the bridge built with overlapping unit blocks could withstand the greatest force. With this fact in mind and some creativity, our group did very well.


The aim of experiment 3 was to investigate the refraction of light rays in water. Refraction refers to the change of direction of a wave due to change of speed.  A paper clip was placed in a cup. From an angle that we can see the paper clip, we slowly changed the angle in which we were looking from till we cannot see it anymore. After that, water was added while our eyes were looking from the same position. To our surprise, we could see the paper clip after water was added! It seemed the light path has changed! We then learnt that it was due to the refraction of light in water.

The refractive index of water is 1.33

"Refraction is described by Snell's law, which states that the angle of incidence θ₁ is related to the angle of refraction θ₂ by

where v₁ and v₂ are the wave velocities in the respective media, and n₁ and n₂ the refractive indices. In general, the incident wave is partially refracted and partially reflected; the details of this behavior are described by the Fresnel equations."


Water has a higher refraction index than air. As the light is reflected from a denser medium to a less dense medium, the light changes its direction and travels to our eyes.

The theme of experiment 4 is mass, weight and density. Here we got to experiment with the density of different objects. They are water, honey, detergent, pebbles, red beans and Styrofoam.

Science E-portfolio (home)

Welcome to my Science E-portfolio blog. Here are the recordings of my science experiments and my reflections and thoughts on them so far in my journey in HCI. Please look through my Blog Archive to view them.

Pang Yong Ray 1P3 21