Hydrogens Unite

12 hydrogen fusion

Hydrogen fusion releases a tremendous amount of energy. However, for hydrogen nuclei to come close together, they must first overcome the very strong electrical repulsive forces between the positively charged nuclei. This is why fusion can only occur at high temperature.

This comic depicts a rally for protons to overcome their “differences”, so as to fuse together and shine as a new star is born. Haha.

Killer Paper

16 Killer Paper

Half-life is the AVERAGE time taken for the activity of a sample of radioactive nuclide to halve.

This comic depicts half the candidates in the examination hall getting “killed” after every 30 minutes, corresponding to a half-life of 30 minutes. Haha.

* Do realize that for actual radioactive decay, a large number of nuclei must be present for half-life to be relevant. Also, radioactivity is random in nature so not exactly half will always decay in exactly one half-life.

Quantum Pay

17 Quantum Bill

Energy of a photon E=hc/λ is inversely proportional to wavelength.

For Gamma rays, energy is delivered in large energy bundles are a few MeV each.

For visible light, energy is delivered by photons that each carries a few eV.

Microwave photons are tiny energy bundles of a few μeV each.

In this comic, Gamma rays, visible light and microwave foot their bill with a million-dollar note, dollar notes, and petty coins respectively. Haha.


Photon Bomb

18 photo bomb

For photoelectric effect, changing the frequency of illuminating light means changing the quantum in which energy is delivered to the metal. Blue light delivers photons that pack more energy each compared to red light.

Photoelectric effect is the interaction between one electron and one photon. This explains why the higher the photon energy, the more energetic the ejected photoelectron. It also explains why there is a threshold frequency below which photoelectric effect cannot occur.

Photoelectric Sniper

20 photoelectric effect

Because light are particles, the photoelectric effect is a one-photon-one-electron interaction, and there is negligible delay between the arrival of the photons and the liberation of the first photoelectron.

If light were waves, the energy delivered must be shared by all the electrons. This ought to result in significant delay between the arrival of the photons and the liberation of the photoelectrons especially when low intensity light is used.

Happy Half-Life-Day

19 Happy half life

At the 10th half-life, the number of undecayed radioactive nuclei in a sample would have dropped to (1/2)10 = 1/1024 of the original number.

In this comic, the sole survivor of 1024 siblings celebrates his 10th half-life alone. So sad.

* Do realize that for actual radioactive decay, the number of nuclei must be large in order for the decay rate to adhere to the exponential decay function. Also, radioactivity is random in nature so not exactly half will always decay in exactly one half-life.

Radioactivity Psychic

21 Radioactive Crystal Ball gazing

Radioactivity is a random process. Meaning the probability of decay is uniform across all the nuclei in the sample. So even though we totally cannot predict which and when an individual nucleus will decay, we can predict that about half of them will always decay after one half-life.

In this comic, this hard fact of life is revealed to a group of helpless nuclei who have zero control over their own fate. Haha.

Spectral Line CSI

22 Spectral Line CSI

A hot gas emits light with an emission spectrum that consists of discrete lines. This is because the energy levels of a gas atom is quantized, meaning it is only capable of emitting photons with energy corresponding to the energy gaps between a pair of allowed energy levels.

Since the energy structure of each element is unique, the emission spectrum for each element is also unique. This forms the basis for spectroscopy whereby we identify the elements in a hot gas by mapping its emission spectrum to characteristic line spectrum of known elements.

In this comic, the detective identifies the murderer to be Sodium gas, whose characteristic line spectrum contains the famous bright doublet at 588.9950 and 589.5924 nanometers. Haha.