An Introduction to sampling This activity could be used prior to carrying out a sampling task in the outdoors

An Introduction to sampling Why do scientist sample? What makes a good sample? How do scientist sample? These questions are answered in this power-point and associated activities

Why do scientists sample? Teachers could add or subsitute current topical issues to this slide. This slide shows 4 images relating to recent news stories where sampling is, or has been, important: Japanese knotweed – this is an introduced species which caused havoc by growing our of control - http://www.environment-agency.gov.uk/homeandleisure/wildlife/130079.aspx Mars – scientists analysed samples from Mars which showed that the conditions in an ancient Mars could have supported life The Scottish wildcat – scientists in Scotland carry out sampling to try to find out how many wild cats there are and if their numbers are decreasing or increasing http://www.scottishwildcats.co.uk/ A plague of frogs in China – scientists need to estimate how many frogs there are, where they are going and what caused this huge increase in numbers

What makes a good sample? If you are going to sample to estimate population size of any animal then it is important that you make sure that you don’t under or over estimate because of the sample. This slide aims to prompt a discussion about the difference in estimated numbers you might get if you took your samples from these 2 areas

What makes a good sample? Scottish Farmers are fined if they do not control the growth of gorse bushes. The hillsides have to be monitored and checked. Surveyors use field sampling and aerial photographs to look at percentage cover.

What makes a good sample? The sample is representative of the whole You do enough sampling to even out random differences

A numeracy challenge! I am developing a sense of size and amount by observing, exploring, using and communicating with others about things in the world around me I can share ideas with others to develop ways of estimating the answer to a calculation or problem, work out the actual answer, then check my solution by comparing it with the estimate I can use my knowledge of rounding to routinely estimate the answer to a problem then, after calculating, decide if my answer is reasonable, sharing my solution with others These are outcomes from the CfE Mathematics document. It is interesting to see how these science activities support these outcomes.

How do scientists sample? This slide could begin a class discussion about how scientists sample and the different systems they need for different situations. The class could then be asked to consider how they might go about sampling a particular species You need a system

These next slides (9-13) can be printed out and given to the pupils – they try to estimate, to sample and to work out how to develop a system. They could be given tiny quadrats made from paperclips. How many armadillos?

How many penguins?

A tricky challenge

What is happening here?

Getting a bit more realistic Take a piece of material 50cm x 50cm and lay out on desk Collect a quadrat 5cm x 5cm Task Try to estimate how many flowers or equivalent are on your piece of material Before you begin discuss your the system you are going to use and write it down Teachers could use pieces of fabric and small 5cm x 5 cm quadrats to sample and to show the importance of having a system to count flowers or other images which are at the edges of the sample site.