Understanding Orders of Magnitude in Science

Hi and welcome back to freesciencelessons.co.uk. By the end of this video you should be able to describe what's meant by order of magnitude. You should then be able to carry out order of magnitude calculations. We've already looked at the words that scientists use to describe the sizes of objects. For example, a millimetre is one thousandth of a metre. However, sometimes scientists want to compare the approximate sizes of different objects. And for this, we use the idea of order of magnitude. This shows an apple and an orange, and you can see that they're about the same size. Scientists say that these are around the same order of magnitude. This shows a pineapple and a small lemon. The pineapple is around 10 times larger than the lemon. So scientists would say that the pineapple is one order of magnitude larger than the lemon. So, one order of magnitude means ten times. OK, here's a dog and down here is a woodlouse. Now, a dog is around 100 times longer than a woodlouse. So, we would say that the dog is two orders of magnitude longer than the woodlouse. The key idea is that every order of magnitude is ten times greater than the one before. An easy way of working that out is to count the number of zeros. This tells you the order of magnitude. So, 10 times is one order of magnitude, 100 times is two orders of magnitude, and 1000 times is three orders of magnitude. Here's a question for you to try. A fox is around 40 cm long. A tick living on a fox is around 0.4 cm long. How many orders of magnitude is the fox longer than the tick? Pause the video and try this yourself. Okay, so the first stage is to work out how many times longer the fox is than the tick. If we divide 40 by 0.4, we can see that the fox is 100 times longer. As I said before, we can work out the order of magnitude by counting the zeros. We've got two zeros, and here they are. So that means that the fox is two orders of magnitude longer than the tick. Remember that you'll find plenty of questions on orders of magnitude in my revision workbook. And you can get that by clicking on the link above. Okay, so hopefully now you should be able to describe what's meant by order of magnitude. You should then be able to carry out order of magnitude calculations.

For example, a millimetre is one thousandth of a metre. However, sometimes scientists want to compare the approximate sizes of different objects. And for this, we use the idea of order of magnitude. This shows an apple and an orange, and you can see that they're about the same size. Scientists say that these are around the same order of magnitude.

This shows a pineapple and a small lemon. The pineapple is around 10 times larger than the lemon. So scientists would say that the pineapple is one order of magnitude larger than the lemon. So, one order of magnitude means ten times.

OK, here's a dog and down here is a woodlouse. Now, a dog is around 100 times longer than a woodlouse. So, we would say that the dog is two orders of magnitude longer than the woodlouse. The key idea is that every order of magnitude is ten times greater than the one before. An easy way of working that out is to count the number of zeros.

This tells you the order of magnitude. So, 10 times is one order of magnitude, 100 times is two orders of magnitude, and 1000 times is three orders of magnitude. Here's a question for you to try. A fox is around 40 cm long.

A tick living on a fox is around 0.4 cm long. How many orders of magnitude is the fox longer than the tick? Pause the video and try this yourself. Okay, so the first stage is to work out how many times longer the fox is than the tick. If we divide 40 by 0.4, we can see that the fox is 100 times longer.

As I said before, we can work out the order of magnitude by counting the zeros. We've got two zeros, and here they are. So that means that the fox is two orders of magnitude longer than the tick.

Remember that you'll find plenty of questions on orders of magnitude in my revision workbook. And you can get that by clicking on the link above. Okay, so hopefully now you should be able to describe what's meant by order of magnitude.

You should then be able to carry out order of magnitude calculations.

Transcript for:Understanding Orders of Magnitude in Science

Transcript for:
Understanding Orders of Magnitude in Science