Term 2 Summary and Reflections

In term 2, I learnt about measurements, physical quantities and units, and Kinetic Particle Theory. 

Firstly, we were taught about unit conversion. This includes units such as nano, micro, deci, etc. I was quite fascinated with all this knowledge as it seemed impossible to measure to such an accurate detail. Also, we learnt how to draw and read proper graphs. This was fairly simple to me.

Next, we learnt how to calculate density and the relationship between density, mass and volume. With this formula, I could solve most density calculations questions. However, there were still certain questions where displacement was involved, and that is also an area I did badly in in this term's test. Also, we learnt about buoyancy. I learnt that air or water can affect an object's ability to sink or float- submarines have this thing called a ballast tank which can be opened to help in sinking or floating! I could see how this applies in real life.

Relationship between mass, density and volume

Lastly, I was taught the Kinetic Particle Theory. The Kinetic Particle Theory, or KPT for short, states that matter is made up of tiny discrete particles which are in constant and random motion. Evidence for this theory is demonstrated by Brownian motion (constant and random motion of small solid particles in fluids) and diffusion (particles moving randomly from a region of higher concentration to a region of lower concentration). Furthermore, electron microscopes have taken X-ray diffraction patterns of crystals- this provides even more evidence that KPT is existent. Moving on, there is the molecular model of the three states of matter.

• For solids, particles are closely packed together in a fixed, regular pattern, occupying minimum space and resulting in high densities. They cannot move freely but vibrate about and are held in position by strong attractive forces. This also explains why solids have fixed volumes and shapes.
• For liquids, their particles are randomly arranged but slightly further apart as compared to solid particles. This is why liquids tend to have high densities. In terms of movement, particles slide past one another and are free to move about but are confined to the vessel containing it. They also have attractive forces between them, which explains why liquids have fixed volume but will take the shape of the vessels containing them.
• For gases, the particles are very far apart and are randomly arranged so they will occupy any available space. This results in them having very low densities. Gas particles have very little attraction between them and move about randomly and at high speeds. This explains why gases have no fixed volume and shape, and why they can be compressed.

After learning about this, I was quite perplexed as there was a lot of information to take in. However, I had learnt about the three states of matter in primary school, so I expected myself to take little time to memorise these facts. Despite this, I still did badly for this particular topic in the test. 

Molecular model of the three states of matter

For this term's test, I scored a 43 (D7). This was a fail and I was quite displeased. I did not do well because of the density calculations and the Kinetic Particle Theory. This was due to the fact that I did not memorise all the facts needed for KPT such as arrangement and movement of particles, etc. I will work harder next term!