French physicist Denis Papin invented the pressure cooker in 1679, which he called ‘Papin’s Digester’. The instrument allowed water to be heated to a temperature higher than boiling point at atmospheric pressure, resulting in considerably high pressure inside. Papin also designed a model of a digester in 1680 that allowed a piston inside a cylinder to move as a result of the action of the steam pressure produced by the heating of the water and blah blah blah.
BUT, contrariwise, the boiling point of water is lower when atmospheric pressure decreases. Theoretically, then, you could attach a suction pump to a pot and suck out the air above the water level, and the water would come to a boil faster – thereby saving energy. How come this technology has not been pursued or developed instead? That is, is there something wrong with the argument?
THROUGHPUT
(The sell-before-date problem was: “40,00,000/80,00,000 are the largest numbers that have this specialty. What is it?”) 40,00,000 is the highest number that can be written in words as FORTY LAKHS without repeating any letter. However, if the alternative spelling LACS is used, 80,00,000 is the highest number that can be written in words as EIGHTY LACS without repeating any letter. -- -J Vaseekhar Manuel, orcontactme@gmail.com
(The second one was: “What’s the numerical value of PLASTERING, given that each alphabet stands for a different digit from among 0 - 9 nine and such that PANS, TIER, and SNAP are three square numerals, and SPA is a factor of PLASTERING?”)
Is it a strange coincidence that for last 10 days or so I haven’t been getting plastered and so I could attempt this problem and get the solution real quick for SNAP/PANS was a dead give-away! Then PLASTERUNG = 9381576402 where SNAP = 1089 = 33^2, PANS = 9801 = 99^2, TIER = 5476 = 74^2, SPA = 198 and finally 198*47381699 = 9381576402. Now, if you tell me that I’m wrong, I’ll gladly go back to my Happy Hour practice! -- Ajit Athle, ajitathle@gmail.com (Cheers then! -- MS)
Since SNAP and PANS are both squares, only numbers which satisfy the condition are 1089 & 9801 . . . etc etc etc . . . Therefore the number 9381576402 which is divisible by 198 is the required number. By the way, whose phone number is it? -- A V Ramana Rao, raoavr@gmail.com (Why don’t you ring up and tell us? -- MS)
(Among the first five who also got it correct are: Vijayalakshmi Sudheer, vijisudheer62@gmail.com; Dr Jawahar Surti, drjsurti@gmail.com; Abhishek Narayan, dudeabhi4u@gmail.com; Shashi Thakur, shashishekher@yahoo.com; Nrusingha Behera, ncb123.age@gmail.com)
(The third problem was: “Hold a pencil three inches above a white sheet of paper under a tubelight such that it is parallel to the tubelight and observe its shadow. Now rotate the pencil through 90 degrees. Why does the shadow change and almost disappear?”)
When the pencil is parallel to the tube the pencil creates an area of umbra which is noticeable. However, no umbra is created when it is turned 90 degrees. Penumbra too may not reach the paper and light from the tube reaches the paper to a very large extent. -- Kishore Rao, kishoremrao@hotmail.com
In the case of a tubelight, area under it is illuminated by light from the full length of the tube. Therefore, shadows are, in general, not sharp or well defined.
When the pencil is aligned along the length of the tube, the shadow is relatively sharper because light from more points on the tube is blocked than when the pencil is turned 90°s from this position. -- Balagopalan Nair K, balagopalannair@gmail.com
The pencil casts a shadow when held along the direction of the tubelight due to coherence of light in that particular direction. However when changed by 90 degrees there is no shadow because it actually produces an interference pattern which is not visible to the naked eye. -- Dr Shyam L, orthoshyam@gmail.com
BUT GOOGLE THIS NOW
1. There are five full bottles of water, five half-full and five empty bottles. How do you divide both the water supply and number of bottles equally between three people?
2. If you take your mechanical watch to the mountains, will it run faster or more slowly than usual? Oh and if you don’t mind, why?
Mukul Sharma
Sharma is a scriptwriter and former editor of Science Today magazine.(mukul.mindsport@gmail.com)