Q&A: your questions, answered

Q&A

We asked CLC to send science-related questions and we chose a few to answer...

Curiosity killed Schrödinger's cat... or did it?

Giselle Chan asked... Are we alone in the universe?

Earth is the only known planet to maintain life. It includes living things, planets, stars, galaxies, dust clouds, light, and even time. There are many possibilities of other life in this universe, we just don’t have the resources to find out. There could be lifebut we can’t get a reliable source to prove that. “Alone “ is a world whose meaning can be easily stretched to fit different perspectives. In my opinion, no-one will ever be truly alone. You're all fitted with imagination and there’s always other things that are alive. So in conclusion no, we could never be alone, our own imagination stops that from ever happening.

Lily Christopherson asked... Why does the Earth orbit the sun rather than being pulled into it?

We know that the sun exerts a huge gravitational force on the Earth because of its immense mass, and the Earth is consequently being pulled towards the sun. But the reason why the Earth does not simply collide with the sun is that there is another force counteracting the gravity of the sun. The Earth in fact has a velocity in the direction perpendicular to the force of the sun’s pull. In other words, without the sun, the Earth would simply travel in a straight line. The outcome of this velocity balancing out with the gravitational force is the stable orbit of the Earth around the sun.

Newton explained the nature of gravitational orbit in the solar system by using the analogy of a cannonball, also known as Newton’s cannon. He imagined an enormous cannonball fired on the Earth. Before it travels far off it simply hits the ground due to gravity. But if it is fired with a stronger force resulting in a greater initial velocity, it travels a bit further before falling onto the ground. If the force becomes extremely large resulting in a much greater velocity, the cannonball will travel far enough that when it falls due to gravity, it will miss the ground because of the Earth’s curvature. Eventually, when this force is big enough, the cannonball will end up constantly falling but never reaching the Earth, or simply, orbiting around the Earth. As there are no external forces that change the velocity of the Earth once it’s "fired" , this is essentially how the Earth orbits around the sun without being pulled into it.

Joanna Guan

Q&A

Nell Darby asked... Why do we remember some dreams vividly and forget others?

Sleep is a fascinating and seemingly straightforward concept that scientists are still trying to understand. It is known that we cycle through 4 stages of sleep every night, each lasting 90 minutes on average. One of these stages is REM (rapid eye movement) sleep, which makes up about 25% of the night. Dreams occur all throughout the sleep stages, but REM sleep is where the most plotbased, narrative dreams occur, which help foster problem-solving abilities, memory consolidation and emotional regulation.

There are a number of factors that may influence how well you recall your dream. First is the stage of sleep from which you wake we have a high chance of encoding dreams we’ ve just had into longterm memory before waking. The process of turning dreams from short to long-term memory can be linked to the temporoparietal junction, a region in our brains that can process information and emotions. Studies have found that people who report a high dream recall showed increased activity in their temporoparietal junctions. In light sleepers particularly, a difference in electrical activity in the temporoparietal junction can mean they are more responsive towards external stimuli during sleep, increasing their tendency of waking. High dream recall amongst light sleepers is therefore frequent as more of their dreams are encoded into long-term memory. Another factor is sleep quantity. Consistent insufficient sleep may sacrifice the quantity of REM sleep, diminishing your ability to recall dreams. Personality traits have also been posited to influence one’s ability to recall their dreams - specifically, creative-

First of all, no. Especially not for humans. Breathing in 100% pure oxygen at normal pressure can cause oxygen poisoning, which could be fatal. When you take in oxygen from the lungs, the oxygen will diffuse across to a transport molecule in the blood called thinking and introspective people are more prone to this ability. Dream recall may also be influenced by emotional impact, which is perhaps the most obvious answer. Vivid dreams, especially those associated with intense, negative emotions, such as those experienced in nightmares caused by stress or trauma, are recalled more easily. It is interesting to note that this form of memory bias can directly be seen in our waking memories as well! So whether you believe dreams are a window to the subconscious, or you just want some bizarre dreams to share over breakfast, tips to increase dream recall include the basics: get adequate sleep and keep a notebook by your bed to record your dreams in the morning before touching your electronics. Vanessa Yip

Ludmila Neil asked... Air is made of 21% Oxygen. Would life function more efficiently if it was 100% Oxygen?

haemoglobin. However, if you breathe air with a much higher than normal oxygen concentration, the oxygen in the lungs becomes too much for the blood to carry away. Instead, the excess free oxygen in the body will react with surrounding tissues, damaging the proteins, fats and nucleic acids in them. This in turn will cause major organs to become dysfunctional, such as your central nervous system and your heart. Broadly speaking, life would also definitely not function if the air was 100% oxygen. This is because, nitrogen, which makes up 78% of the air, has an important role for life function as well. It is especially essential for many microorganisms and plants to live. Some bacteria can fix the nitrogen in the air into nitrates, a mineral that plants can absorb, which in turn allows them to produce the proteins that our human bodies cannot make. Unlike oxygen, nitrogen is an unreactive gas, so it provides the atmosphere with a nice and stable environment. Even with more than 30% of oxygen in the air, many substances would spontaneously burst into flames meaning that life could not exist at all. Nitrogen "diluted" the oxygen to a concentration where it is perfect for life to develop on Earth. Vanessa Tsui

Lily Christopherson also asked… What makes your hair straight or curly?

If you look at other members of the Ape family, no other species have curly hair, so why did humans develop them and what exactly causes hair to be curly? All over your skin, there are deep pits known as follicles from which hair grows. Some theories suggest it is the shape of the hair follicle which determines your hair’s tendency to curly or straight. A study in New Zealand (unsurprisingly) looked at the hair follicles of sheep to see how they contributed to hair type. They predicted that the curly hair follicle would have more hair producing cells on one side of the follicle than the other, as this would make the hair grow asymmetrically (in other words, it would be longer on one side which would cause it to bend in one direction). However, they found no evidence that the shape or distribution of hair-producing cells in the follicle had any effect on hair type. So, perhaps looking more closely at the structure of hair will help answer our question.

You may have seen microscope images of hair with an outer layer of dead cells which have a scaly appearance. Underneath this layer is a matrix made mostly from keratin proteins. Keratin is the same substance that forms a rhinoceros's horn, a horse's hooves and a sardine’s scales. Being a protein, keratin is formed from long chains of amino acids. Imagine a protein as a daisy chain, and if you had many varieties of daisy in a garden, you could make chains with many different colour variations. Similarly, proteins with different properties are produced when twenty types of amino acids are put in different combinations. These keratin proteins can form bonds between each other, known as hydrogen bonds, creating strands of protein called fibrils. This is similar to how a rope is formed from many small fibres. The subtle variations in amino acids of keratin proteins determine how they interact with each other. The uneven way they are laid out in the hair matrix will influence a hair's strength and, perhaps, determine its tendency to curl. To illustrate this point, when hair is straightened, heat overcomes the hydrogen bonds between the keratin proteins. When the hair cools, the proteins reset into a new layout and new hydrogen bonds re-form once again. Over time, the effect of the straightening wears off as the protein molecules move back into previous configurations. Equally, getting a perm involves breaking much stronger bonds called disulphide bridges using chemicals and heat and reforming them to form curly hair. Despite this being a sensible theory, hair is still a complex structure, and its properties are determined by a wide range of genes. A study collected genetic data on 6,000 people in order to find associations between genes and their hair types. They discovered two genes, one which results in a structural hair protein called Trichohyalin (TCHH) and another called EDAR (responsible for sending messages in the cells). TCHH plays a role in the way keratins interact with each other and EDAR promotes symmetrical hair growth. Interestingly, TCHH was found to have evolved in Europeans independently of EDAR, which evolved in East Asians, suggesting there is more than one way to get straight hair. Looking at other global populations may provide deeper insight into why hair is different. Whilst there is a plethora of stunningly creative African hairstyles - the predominantly coiled feature of hair of people of sub-Saharan descent is believed to protect from intense UV radiation whilst keeping the head cool. This may have evolved when early humans ventured from forested habitats into open savannah millions of years ago. At this time, humans also lost much of their body hair as we became more proficient at sweating - an adaptation which made us incredibly good at chasing animals for food. As humans migrated out of Africa to higher, cooler and less sunny latitudes, coiled hair may not have been so beneficial. It was then that the TCHH and EDAR genes arose in European and Asian populations. So, why did these migrants lose their curls? A warm dense layer on the head, ears and neck would have helped keep humans warm during the colder winters. Others argue that our hair played a limited role in heat regulation, that perhaps it had a more important role in signalling social or reproductive status, or that it arose due to sexual selection pressures in those populations. From my research, it is a much more complex question than I first thought. Keratin protein interactions, mutations in genes and evolutionary selection pressures all combine to form a surprisingly fascinating puzzle. This perhaps might not be the definitive answer you were after, but uncertainty is the true nature of science. Mr Mallin asked one of his LC1s (Sophia Edwards) to draw an ancient mammal with the question “Why did they evolve hair?” and she came up with this - An Emo Therapsid. (Lily and Vanessa love it. It’s genius). Mr Mallin