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Okay I understand that it cannot be explained to a 5 year old. But, how do you explain the logarithm to primary school students?

  • 7
    You would need some very gifted students to get close to explaining it. Fair enough for simple bases (and taking logs of simple numbers which are obvious powers of those bases) you might achieve your goal but a general understanding of logarithms is out of the question at such a young age. Also, say you have such students, why should they know about logarithms at such a young age when they have yet to grasp other less sophisticated concepts? They are almost certain NOT to appreciate the notion as something wonderful but as something randomly taught to them.2012-04-07
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    I know this is not strictly explaining logarithms to children, but it may help with the connection. From a young age I had many earthquakes in my country (NZ), and we knew that the earthquakes worked on a Richter scale, which happens to be logarithmic. We knew that 6 was 10x greater than 5. Often children just need to know why something is useful before they start trying to understand it. Lazy loaded learning.2012-04-07
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    How many 2 is required so that 2*2*...=64?2012-04-08
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    "2x2" how many times equals 64?2012-04-08
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    To a -5- year old? Aren't you stretching the limits of relevance? Most (even bright) kids are only about to 'get' negative numbers (which is arguably a much prior concept (inverse of addition) that is much more accessible. If this is just for fun (for a child that can 'get' things), then @JohnS's example looks to be aan excellent idea with lo-tech/lo-conceptual overhead.2012-04-08
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    How many times we need to half a cake to make it small enough?!2012-04-08
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    @enthdegree: you can calculate 2x2 as many times as you want, but it will never equal 64...2012-04-08
  • 1
    You would minimize the math itself and focus on the growth and magnitude. Use a concrete example, like having babies. A human might have one baby per year. A dog might have four. A rabbit might have twenty. Compare the populations after several generations of growth for each group. A small difference in the logorithmic function of babies per year can make large differences in the population after several years.2012-04-08
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    Interestingly, I have read that young children actually initially have a logarithmic understanding of numbers (i.e. they think that 10 is the same distance from 100 as 100 is form 1000 on a number line). For example, see [here](http://www.ncbi.nlm.nih.gov/pubmed/15056197). They then have to unlearn this logarithmic conception of the number line.2012-04-08
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    As the comments indicate, maybe some contextual detail would be helpful. Is a five-year-old asking what a logarithm is because he heard his big brother talking to you about it? Or are you trying to explain something that is measured on a logarithmic scale, like sound or the strength of an earthquake? The answer to that will tell us how specific the answer needs to be, and/or how to explain it in terms of the context in which the five-year-old heard about it.2012-04-09
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    In the first place you should explain that logs are a means to handle very large and very small numbers simultaneously, like distances of stars, sizes of people and sizes of bacteria, or number of people at 2000 B.C., 0 A.C., 1200,1900, 2012, 2050.2012-04-09
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    @Mitch abstractly you're right, but when your kid comes up to you and says "Daddy, what's this button on the calculator do?"; saying "I'll explain it to you in 10 years" probably isn't going to go over well.2012-04-10
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    @DanNeely: Yes, you're right. There are many contexts where an explanation could work/be meaningful and useful to a 5 yar old (JohnS keeps coming up with good ones). I think I was caught up in the symbol manipulation. But I still think the simple 'number of digits' concept, which would totally work for older kids (8-10 yoa) would be obscurantist to even a curious 5 year old.2012-04-10

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