Copyright © University of Cambridge. All rights reserved.
Thank you to those of you who sent
solutions to this problem. Unfortunately, though, not many of
you explained how you knew the order in which to put the
quantities.
Katie from Hymers College Junior School took
us through the first set of quantities:
First of all I am going to tackle the temperature question.
First you look at what to rank
*Of a kettle of boiling water
*Of the centre of the sun
*On a thermometer when you are
quite well
*Of the water in a school
pond
Then you think about the ones that you know the temperature.
So it is clear that the sun is the hottest. So now tick that off
the list.
Then you think, well our school pond is quite deep and therefore
quite cold. So compared to the rest of the list the pond is the
coldest so now you can check that off the list.
Now you are left with the two middle answers. Everybody knows that
water boils at $100^\circ$ and your body temperature is around
$38^\circ$. From this research you now know that the kettle of
boiling water is the second hottest. Now you can tick that off the
list.
Finally you are left with the last one to tick off the list, the
temperature of the thermometer when you are quite well.
So now they are all ticked off the list you can put them into their
final order which is:
1. Of the centre of the sun.
2. Of a kettle of boiling water.
3. On a thermometer when you are quite well.
4. Of the school pond.
Katie then ordered the speed, time and sound
quantities:
Speed:
1. Of a rocket going up on bonfire night
2. Of a train
3. Of a ball being thrown to your friend
4. Of a ladybird walking along a leaf
Time
1. Taken for frogspawn to grow into a frog
2. Taken for the moon to orbit the earth
3. Taken for a puddle of water to evaporate on a hot day
4. Taken to walk across the playground
Sound
1. Of a clap of thunder
2. Of a teacher blowing a whistle
3. Of a tap running
4. Of a recorder being played by a friend
The last one and the whistle depend on how hard they blow. For
number 4, the friend is a controlled recorder player and for number
2, the teacher is having a bad day so is very loud.
Thank you, Katie. I like the way you've
given us more information about the sound quantities. Someone
from Ricards Lodge who didn't give their name, gave a different
answer to the sound part of the problem:
For the sound category the loudest sound is a clap of thunder,
then it's a teacher blowing a whistle, next it's your friend
playing a recorder, and finally the quietest sound is a tap
running.
To find this out I knew thunder would be the
loudest.
Then I tested whether a recorder was louder than a tap,
and it was, so then I tested whether a recorder was louder
than a whistle, but it wasn't and that is how I got my order.
Your results may be different depending on your equipment. But
these are the results I got.
It's interesting that there is a differing
opinion about these sound quantities. However, it is great
that Katie and the pupil from Ricards Lodge have both explained
their own reasoning. Well done! I wonder what you
think?