How do you estimate the population of fish in a lake ?
What is convection ?
the transfer of heat through the movement of fluids (liquids or gases) due to density differences
What is Radiation heat transfer ?
the transfer of thermal energy as electromagnetic waves (like infrared, visible light, UV) that travel through space or a medium, requiring no physical contact or medium (like air or water) to occur,
What is sublimation ?
substance changes directly from a solid to a gas, skipping the liquid phase, like how dry ice vanishes.
Trick to conceptualise metric length ?
1 mm → credit card thickness
1 cm → fingernail width
1 m → door handle height
1 km → 10-minute walk
How much is 1 atm equivalent to in bars ?
1 atm ~ 1.013 bar.
What is Styrofoam made of?
Expanded polystyrene (EPS), a plastic made from styrene derived from petroleum. It is ~95–98% air.
What is polystyrene?
A polymer made by linking many styrene molecules together.
What dissolves Styrofoam (EPS)?
Organic solvents like acetone, petrol (gasoline), toluene, and xylene.
Why does Styrofoam “melt” in acetone?
The solvent breaks down the polystyrene structure and releases trapped air, causing the foam to collapse.
What is polymerisation?
A chemical process where many small molecules (monomers) join to form long chains (polymers).
What is the monomer of polystyrene?
Styrene.
