06.09.2019: One Chapter of Science – Matter, Properties, and Phases

Today’s soundtrack is Pearl Jam: Ten, the grunge band’s powerful debut album.

This morning, I’m reading the sixth chapter of Everything You Need to Ace Science in One Big Fat Notebook, “Matter, Properties, and Phases.”

Matter is made up of atoms, and is “anything that has mass and takes up space (including air and almost everything else)” (p. 60). Atoms are made of protons, neutrons, and electrons. At the centre of an atom are protons and neutrons. The former are particles with positive charge; the latter have no electrical charge. Orbiting this nucleus we find electrons, which are particles with a negative charge.

We can classify different kinds of matter by their physical properties, which include malleability, magnetism, boiling/melting/freezing points, and solubility. Physical changes to matter can change its form (for example, we can change a solid metal to a liquid by melting it, and we can change it back to a solid by cooling it).

Chemicals, instead of being classified by a physical property, are classified by their chemical properties, which include flammability; “reactivity (how reactive something is to oxygen, water, light)” (p. 63), or other chemicals; combustion temperature; and toxicity.

A chemical’s properties can be changed through interaction with external forces. An example given in the book is rust on an iron gate. Signs of changes can include changes in colour, energetic reactions, and changes in odour. Unlike physical changes (which can often be easily reversed), chemical changes are often impossible to reverse.

Even as matter changes through either physical changes or chemical changes, one thing is constant: the mass of the matter. The rule of conservation of mass tells us that “[t]he amount of mass at the start of a reaction will equal the amount of mass after the reaction” (p. 65).

Most matter exists in one of three phases (or forms): solid, liquid, and vapour. What determines its form at any given time is “[t]he arrangement and behavior of [its] particles” (p. 65). The following table that I found on page 67 of the book illustrates the concept of phases nicely:

STATEFEATURESMOVEMENT OF PARTICLES
SOLIDFixed shape and volumeVibrate, but have fixed positions
LIQUIDShape can change; volume is fixed. Can flow. Free-moving – no fixed positions.
GASShape and volume not fixed and depends on container. Can flowParticles move quickly and are far apart

In phase changes, we use several terms to describe what happens: melting (when a solid turns into a liquid), freezing (when a liquid turns into a solid), vaporization (when a liquid turns into a vapour), condensation (when a vapour turns into a liquid), sublimation (when a solid changes directly into a vapour), and deposition (when a vapour changes directly into a solid).


Summary:

  1. The positively charged particle in an atom is a proton.
  2. Thomson believed an atom was like an oatmeal raisin cookie, with electrons spread about like raisins.
  3. If I turn eggs, flour, and milk into pancakes, the ingredients have undergone a chemical change. If I turn a banana, strawberries, and yogurt into a smoothie, the ingredients have undergone a physical change.
  4. If I burn a piece of paper, there is still the same amount of mass after as there was before; it’s just taken a different form.
  5. Some things that are not matter include the void of space, the spoken word, and darkness.
  6. The difference between a liquid and a vapor is that in a liquid, the particles flow freely; in a vapour, the particles are trying to get away from each other. The volume of a vapour can be more than that of a liquid, because the vapour can disperse.
  7. At the boiling point of a substance, the liquid begins to turn into a vapour.
  8. The molecular movement in a solid is stationary but wiggling; in a vapour is moving quickly all over the place; in a liquid is free-flowing.
  9. Viscosity is how much matter sticks to itself how resistant a matter is to flowing. Peanut butter has higher viscosity than ketchup.
  10. Vaporization is when a liquid turns to a vapour (water being boiled and turning to steam). Condensation is a vapour turning into a liquid (the air around a cold can of pop turning into droplets of water).

That’s it for today! Next time, we’ll be learning about the periodic table, atomic structure, and compounds.

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