Good luck to all the Chemistry Standard Grade students who have the dubious honour of kicking off this year’s SQA Exam schedule on Thursday morning!
Remember your monkeys eating peanut butter!
Monthly Archives: April 2008
A race to the bottom…
A solid block of iron and an equally heavy iron sphere are released from the top of a slope.
Assuming that the friction from the slope has a negligible effect on the velocity of the block and the sphere, which of the two will get to the bottom first?
Puzzle Tower
Suppose you have an infinite number of bricks and no cement or another material to connect the bricks to each other. You would like to build a tower like the one in the figure. How many bricks do you need in order to build a tower in which the highest brick is shifted three bricks with respect to the lowest brick?
7 day count down!
The Chemistry Standard Grade exam is on Thursday May 1st – exactly 7 days from now!
All pupils should already be working hard on their self-revision – and bringing in any questions or problems or requests into class during the day, so that teachers can advise or assist.
Please remember that there are a number of resources available to you in making your revision rigorous, varied and worthwhile. These include:
- Past Papers
- Revision guides
- Bitesize books and website (www.bbc.co.uk)
- Teacher worksheets
- Evans Chemweb (see link from here)
- Peer revision – get together with a classmate and test (and learn from) each other!
- After school revision (the Wednesday 3.45pm classes have run all term)
Good luck with your revision! Remember the short term pain working at home for this coming month will be worth it – your exam marks will reflect your effort in revising!
An Archimedes riddle…
Archimedes was no slouch! The Greek mathematician was also a physicist, engineer, inventor and astronomer in his spare time!
He is most well known for his “Eureka moment”…
The most commonly related anecdote about Archimedes tells how he invented a method for measuring the volume of an object with an irregular shape. According to Vitruvius, a new crown in the shape of a laurel wreath had been made for King Hiero II and Archimedes was asked to determine whether it was of solid gold – or whether silver had been added by a dishonest goldsmith. Archimedes had to solve the problem without damaging the crown, so he could not melt it down in order to measure its density as a cube (which would have been the simplest solution).
While taking a bath, he noticed that the level of the water rose as he got in. He realised that this effect could be used to determine the volume of the crown. For practical purposes water is incompressible, so the crown would displace an amount of water equal to its own volume. By dividing the weight of the crown by the volume of water displaced, its density could be obtained.
In other words, the density of the crown would be lower if cheaper and less dense metals had been added…
Archimedes then took to the streets naked (so excited by his discovery that he had forgotten to dress!) crying “Eureka!” (“I have found it!”)
So what is your Archimedes Riddle?
You are sitting in a rubber boat in a swimming pool. In the boat lies a stone. You throw this stone from the boat into the pool. Will the water level in the pool rise or drop?
Over to you…
4th Science teaser
My laundry was recently spattered with ‘little messages’ from a local band of marauding blackbirds. My first question was ‘Why do they have such a good aim, hitting only my washing?’ Then I got to thinking, if these birds eat little black insects, worms, occasional seeds, bread etc, why are their droppings white?
So, can you tell me why bird droppings are the colour they are?
Answer to 3rd Science teaser
Well done to Ottalie, our resident ‘eggspert’.
As she says, some people have proposed that eggs are shaped as they are to prevent them rolling off/out of the nest. There is evidence that seabird eggs are less spherical (rounded) so they can roll in a tighter arc and are less likely to roll out of the nest. Other reasons given have been that it allows eggs to fit more snugly together in the nest, with smaller air spaces between them, This will cut down on heat loss.
Lastly, the shape of an egg does give a great degree of mechanical strength. Try applying equal pressure to all sides of an egg at the same time. It is hard to break the egg. I’ve seen a kid actually stand on the top/pointed end of an ostrich egg and it didn’t break (see picture above)
However, recent research in Belgium (Brussels Institute of Oology) has shown selective pressure on egg shape in battery chickens to evolve to fit standard Ikea egg cups. Allegedly……….