Let’s start with a quiz…
- How many senses do you have?
- Which of the following are magnetic: a tomato, you, paperclips?
- What are the primary colours of pigments and paints?
- What region of the tongue is responsible for sensing bitter tastes?
- What are the states of matter?
If you answered five; paperclips; red, yellow and blue; the back of the tongue; and gas, liquid and solid, then you would have got full marks in any school exam. But you would have been wrong.
The sixth sense and more
Taste, touch, sight, hearing and smell don’t even begin to cover the ways we sense the world. We sense movement via accelerometers, which are located in the vestibular system within our ears. The movement of fluid through tiny canals deep in our ears allow use to sense movement and give use our sense of balance. Make yourself dizzy and its this sense that you are confusing.
When we hold our breath we sense our blood becoming acidic as carbon dioxide dissolves in it forming carbonic acid. Not to mention senses for temperature, pain and time plus a myriad of others that allow us to respond to the need what is going on within us and the environment around.
It is not just paperclips that are magnetic. Both tomatoes and humans interact with magnetic fields, too.
Paperclip and other objects that contain iron, cobalt and nickle are ferromagnets, which means that they can be attracted to magnetic fields. While the water in you and the tomato – or more accurately the nuclei in the hydrogen in the water in you and the tomato – is repelled by magnetic fields. This interaction is called diamagnetism.
But the forces involved are incredibly weak. So normally you don’t notice them. That is unless you have been in a magnetic resonance imaging (MRI) machine. In there, a massive magnet manipulates nuclei of various atoms inside you in such a way that results in detailed images of your inner workings.
Though you don’t need to go to a hospital to see diamagnetic interactions. Just use a couple of cherry tomatoes, a strong magnet, a wooden kebab stick and a pin:
And the types of magnetism don’t stop there, but that’s for another time.