Science: Technoquest: Roman times tables/Lightning gaps/ Oceanic crust/Collapsing plastics
Questions for this column may be submitted via e-mail to sci.net@campus .bt.com
Your support helps us to tell the story
From reproductive rights to climate change to Big Tech, The Independent is on the ground when the story is developing. Whether it's investigating the financials of Elon Musk's pro-Trump PAC or producing our latest documentary, 'The A Word', which shines a light on the American women fighting for reproductive rights, we know how important it is to parse out the facts from the messaging.
At such a critical moment in US history, we need reporters on the ground. Your donation allows us to keep sending journalists to speak to both sides of the story.
The Independent is trusted by Americans across the entire political spectrum. And unlike many other quality news outlets, we choose not to lock Americans out of our reporting and analysis with paywalls. We believe quality journalism should be available to everyone, paid for by those who can afford it.
Your support makes all the difference.Q How did the Romans do multiplication - instead of 103 times 22 would they have to manipulate CIII x XXII?
The answer is, with great difficulty. Instead of calculating with pencil and paper, they would have used an abacus to actually do the calculations, and then written the answer in Roman numerals. Division would have been even harder - involving breaking the calculation into a number of operations like those we now use in long division.
You might wonder why they didn't develop a positional number system like ours: the answer is probably because they didn't have a symbol for 'zero' (try doing maths without it) which was introduced later, by the Arabs.
Q Where does the word "photon" come from?
The term comes from the Greek word phos or photos, meaning light. But the word photon wasn't used until 1926. Before that a "particle" of light was called a light quantum.
Q Why don't lightning and thunder occur at exactly the same time?
Actually, they do: thunder and lightning always occur together in a storm. But most people aren't present at the point where the lightning hits. Instead, you usually witness the event some distance away. The light from the lightning travels much faster than the sound from the thunder, so the light reaches you almost instantaneously. But it takes about five seconds for sound to travel one mile. By counting the number of seconds between the lightning flash and the thunder, you can calculate how far away the storm is.
Q What's the ocean floor made of, and how thick is it?
The crust beneath the ocean differs from the crust beneath the land in several ways: it is thinner, denser, younger and made in different ways. Both have rocks made up of the same minerals, just in slightly different proportions. The crust has silicon, aluminium, iron, magnesium, calcium, sodium and potassium oxides in it - just like any other rock. However, the oceanic crust is only about four miles thick.
Q When you defrost something in a plastic container in a microwave, you often end up with a collapsed container - as if something had sucked the sides in. Why?
As you defrost things, the water on the surface escapes into the air in the container. A lot of this water will escape as superheated steam from the container, through the tiniest pores in the seal of the lid. But because these containers are designed to keep food fresh by keeping out bacteria, no air can get back in to fill the space left by the departing water. This means the air pressure inside the container is less than that outside, so the sides of the container cave inwards.
You can also visit the Technoquest World Wide Web site at http:/www.sciencenet.org.uk Questions and answers provided by Science Lines' Dial-A-Scientist on 0345 600444
Join our commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies
Comments