Skip to 0 minutes and 6 secondsHere are three constants that regularly occur in science. Again, you have to determine which order they are in terms of size. The first is Avogadro's Number. This is 6.02 times 10 to 23 per mol. This is an enormous number, due to the multiplication of 10 to the power 23. The next number is pi. This is 3.14, and so on. This number goes on forever, and never repeats itself. But it's still roughly 3, which makes it much smaller than Avogadro's Number. The next number is Planck's Constant, which is essential in physics. Planck's Constant is 6.63 times 10 to the minus 34 joule seconds. The multiplication of 10 to the minus 34 makes Planck's Constant an extremely small number.

Skip to 1 minute and 2 secondsMuch, much smaller than pi, which in turn is much, much smaller than Avogadro's Number. Finally, we have e which is the base of natural logarithms. This number is 2.72, and so. This makes it just a bit smaller than pi. With this amount of information, you should be able to tell the order in which the numbers fall. Planck's Constant is by far the smallest, e is the next, pi is a little larger than e, and Avogadro's Number is by far the largest. You can find the values of these numbers easily in most scientific textbooks, or by searching the internet.

# Self assessment: comparing weights of cakes

The video contains the answer to the questions of ordering a series of numbers.

Have a go at another question about cakes:

Which weighs more; ^{6}/_{11} of a cake where the whole cake weighs 1.35kg or ^{4}/_{15} of a cake where the whole cake weighs 2lbs 9oz (1 lb = 454g, 16oz = 1 lb )