Chapter 1: Understanding Magnets

In order to tackle this puzzle, you may want to revisit your science textbooks. Today, we delve into the fascinating realm of magnets.

What exactly is a magnet?

A magnet is typically a metallic object characterized by distinct north and south poles, where opposite poles attract and similar poles repel. The behavior of a magnet arises from the movement of electrons, which exhibit both uneven orbits and spins.

One key observation about magnets is their interactive behavior: when opposite poles are brought close together, they attract, while like poles push away from each other. For a long time, the underlying reasons for this phenomenon remained a puzzle. So, what causes this intriguing behavior?

While it may seem that the magnet itself is stationary, the reality is that there are charges within it that are in motion. Electrons revolve around the nucleus of each atom, and when charges move, they generate magnetic fields. In many non-magnetic materials, the electrons move in both directions, resulting in their magnetic fields neutralizing each other. However, in certain magnetic materials, such as iron, there is an unequal number of electrons moving in opposite directions, leading to the emergence of an overall magnetic field.

Moreover, another type of movement comes into play: quantum mechanical spin. Electrons that spin in a particular direction create a magnetic field. When the spins of all the electrons do not cancel out, a magnetic field is produced.

Now, let's get to the puzzle...

Your friend presents you with two iron rods.

At least one of these rods is a magnet. Your task is to figure out whether each rod is magnetic or not.

Note: You are permitted to use any non-metallic object to assist in your determination. Here are the items at your disposal: a plastic container filled with 1 liter of water, 1 kg of rock salt, half a kg of grass from your garden, 1 kg of non-magnetic sand, a 30 cm wooden pipe, a 1-meter string, a box of cigarettes, and an A4 sheet of plain paper.

Enjoy the challenge!