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Seeds of doubt
Last words past and present at newscientist.com/lastword
THE LAST WORD Seeds of doubt Can anyone solve a mystery several decades old by identifying this seed pod (see photo)? It was collected on a beach just north of the town of Budva, in what is now Montenegro, in August 1967. A stream ran down to the beach from a marshy valley, and there were wooded hills on either side.
n The mystery seeds are those of the Eurasian water chestnut, Trapa natans. I have seen it growing abundantly on Lake Skadar, which straddles the border between Montenegro and Albania, not far from Budva. The seeds are edible, but need to be boiled to remove a toxin.
The plant is sometimes called water caltrop, from medieval Latin calcatrippa (foot-trap): a reference to its pointed shape, which resembles the eponymous anti-personnel weapon that dates back as far as the 3rd century BC. Caltrops were cast on the ground to slow attacks using horses, elephants, camels or human troops. They continued to be used during the second world war against pneumatic tyres, with good effect. Harry Percy Ludlow, Shropshire, UK
“The seeds are the Eurasian water chestnut, which are edible but need to be boiled to remove a toxin”
This week’s questions Nettling conundrum
Can any readers identify this object (see photo) growing on a stinging nettle of the species Urtica dioica? The nettle was beside a gravel drive, and there are some small patches on the underside of the leaf ribs. Elizabeth Herd By email No address supplied Waning woodpile
Sometimes the wood at the bottom of our woodpile decays to the point where it has only a small fraction of its previous dry mass. What has happened to it? Where did all the carbon go? From the point of view of greenhouse gas emissions, is it better for the wood to be burned in my fire or for it all to rot back into the earth? Peter Seligman Victoria, Australia Head space
My thoughts feel as though they are in my head. Is there a physical basis for this, or is it just that I know that’s where my brain is? Julian Richards London, UK Air drumming
When I open my car windows while driving, everyone inside can hear a helicopter-like thumping sound. It is even worse when the rear windows are opened and it gets louder at
The writers of answers that are published in the magazine will receive a cheque for £25 (or US$ equivalent). Answers should be concise. We reserve the right to edit items for clarity and style. Please include a daytime telephone number and an email address if you have one. New Scientist retains total editorial control over the published content. Reed Business Information Ltd reserves all rights to reuse all question and answer material that has been
submitted by readers in any medium or in any format and at any time in the future. Send questions and answers to The Last Word, New Scientist, 110 High Holborn, London WC1V 6EU, UK, by email to [email protected] or visit www.newscientist.com/topic/lastword (please include a postal address in order to receive payment for answers). Unanswered questions can also be found at this URL.
higher speeds. What causes this phenomenon? Oscar Holroyd Herefordshire, UK Drying dilemma
Which method of drying my hands uses less energy: an electric blow-dryer or a paper towel made of dried wood pulp? Ian Cutter Victoria, Australia Choc chip
Why does the chocolate on the outside of ice-creams and other frozen desserts always crack and fall into your lap when you bite into them? Why has science found no answer to this problem? Volker Haupt Vienna, Austria
Question Everything The latest book of science questions: unpredictable and entertaining. Expect the unexpected Available from booksellers and at newscientist.com/questioneverything
THE LAST WORD Seeds of doubt Can anyone solve a mystery several decades old by identifying this seed pod (see photo)? It was collected on a beach just north of the town of Budva, in what is now Montenegro, in August 1967. A stream ran down to the beach from a marshy valley, and there were wooded hills on either side.
n The mystery seeds are those of the Eurasian water chestnut, Trapa natans. I have seen it growing abundantly on Lake Skadar, which straddles the border between Montenegro and Albania, not far from Budva. The seeds are edible, but need to be boiled to remove a toxin.
The plant is sometimes called water caltrop, from medieval Latin calcatrippa (foot-trap): a reference to its pointed shape, which resembles the eponymous anti-personnel weapon that dates back as far as the 3rd century BC. Caltrops were cast on the ground to slow attacks using horses, elephants, camels or human troops. They continued to be used during the second world war against pneumatic tyres, with good effect. Harry Percy Ludlow, Shropshire, UK
“The seeds are the Eurasian water chestnut, which are edible but need to be boiled to remove a toxin”
This week’s questions Nettling conundrum
Can any readers identify this object (see photo) growing on a stinging nettle of the species Urtica dioica? The nettle was beside a gravel drive, and there are some small patches on the underside of the leaf ribs. Elizabeth Herd By email No address supplied Waning woodpile
Sometimes the wood at the bottom of our woodpile decays to the point where it has only a small fraction of its previous dry mass. What has happened to it? Where did all the carbon go? From the point of view of greenhouse gas emissions, is it better for the wood to be burned in my fire or for it all to rot back into the earth? Peter Seligman Victoria, Australia Head space
My thoughts feel as though they are in my head. Is there a physical basis for this, or is it just that I know that’s where my brain is? Julian Richards London, UK Air drumming
When I open my car windows while driving, everyone inside can hear a helicopter-like thumping sound. It is even worse when the rear windows are opened and it gets louder at
The writers of answers that are published in the magazine will receive a cheque for £25 (or US$ equivalent). Answers should be concise. We reserve the right to edit items for clarity and style. Please include a daytime telephone number and an email address if you have one. New Scientist retains total editorial control over the published content. Reed Business Information Ltd reserves all rights to reuse all question and answer material that has been
submitted by readers in any medium or in any format and at any time in the future. Send questions and answers to The Last Word, New Scientist, 110 High Holborn, London WC1V 6EU, UK, by email to [email protected] or visit www.newscientist.com/topic/lastword (please include a postal address in order to receive payment for answers). Unanswered questions can also be found at this URL.
higher speeds. What causes this phenomenon? Oscar Holroyd Herefordshire, UK Drying dilemma
Which method of drying my hands uses less energy: an electric blow-dryer or a paper towel made of dried wood pulp? Ian Cutter Victoria, Australia Choc chip
Why does the chocolate on the outside of ice-creams and other frozen desserts always crack and fall into your lap when you bite into them? Why has science found no answer to this problem? Volker Haupt Vienna, Austria
Question Everything The latest book of science questions: unpredictable and entertaining. Expect the unexpected Available from booksellers and at newscientist.com/questioneverything