From eyebrows to phone battery life... and alphabet of questions

The second-year science students in Adamstown Community College, Lucan (Ms Corrigan’s class) prepared the following questions as part of the recent Stop & Ask campaign for Science Week, writes Dr Naomi Lavelle

There is more to come in the next column.

Why do we have toes?

All land mammals have toes; some, like primates, use them for gripping while climbing trees. Our toes are adapted instead to what we do best, walking on two legs. Our toes help us to balance, allowing subtle shifts in weight distribution as we walk, especially when walking on uneven surfaces.

What are butterflies in your stomach?

Butterflies in our stomach are caused by an automatic response in the body called the fight-or-flight mechanism; this is the same response used by early humans to keep themselves from harm but we have not evolved to distinguish the sound of a potentially life-threatening animal in the path ahead, from having to stand up in front of a crowd of people and give a presentation.

Both scenarios trigger a similar fear response where the body instantly diverts blood to areas that may need it for a quick getaway, namely the muscles of our arms and legs. The fluttering sensation we feel is a local reaction to this sudden change.

Why can’t we have phone batteries with endless life?

Lithium-ion batteries are typically used in smartphones and other devices. These batteries can be recharged repeatedly, but, over time, they hold charge less efficiently and require more frequent charging. This is because the lithium eventually corrodes.

Scientists have created new battery prototypes that greatly extend the life of the battery (recharging up to 20,000 times with little degradation) but these batteries are still in the early stages of development and are often made with expensive raw materials.

Why are metals such good conductors of heat?

The outer electrons of each atom of metal are not held firmly by the atom, as with most other materials, instead they can move more freely through the lattice of the metal, forming clouds of electrons. Electricity is the flow of electrons; as these delocalised electrons can easily flow through the metal they are good at conducting electricity.

Why is urine yellow?

Urine contains pigments called urochrome or urobilin that gives it a yellowish colour. 

Both pigments are produced from the breakdown of blood products, urochrome is produced as dead blood cells are broken down in the kidneys and urobilin is created as haemoglobin is broken down from red blood cells.

How much does earth weigh?

It is more accurate to say what the mass of the Earth is, and it is estimated at about 5.9736×1024 kg. How is this calculated? Using a formula that was first devised by Issac Newton in 1687.

Why do we need eyebrows?

Humans rely heavily on their sense of sight so it is important to prevent any possible obstruction of our vision. Our eyebrows help with this, keeping water and sweat from our eyes.

So while our body hair became finer as we evolved, we kept the bushy eyebrows.

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