A worksheet aimed at advanced level biology students, this resource is useful as a review of how colorimeters work and how they should be operated. The second worksheet contains a list of questions on different types of error that may result from laboratory investigations, some of which may be experienced when using a colorimeter: zero errors, systematic errors and random errors. The third worksheet is a differentiated version of the above, with an emphasis towards more simple ideas on the difference between qualitative and quantitative errors and calibration curves.

A complete summary of all three main statistical tests required for AQA Biology: 95% confidence limits and standard error, spearman rank and chi-squared. The worksheet focuses on the basic routine of each test rather than getting bogged down with detailed explanations of the theory behind them. A useful resource to give to students as a summary once statistical tests have been taught. Each summary provides data for students to analyse and practice each test. There is also a quick quiz at the start, whereby students need to select the appropriate statistical test for each investigation. Key words: Statistical tests, 95% confidence limits, standard error, chi-squared, spearman rank, maths, degrees of freedom, critical value, probablity, null hypothesis

A resource aimed at advanced biology students, this worksheet provides some more unusual examples of dihybrid cross genetics including malvidin production in primrose, kernel colour in wheat and fruit colour in squash; all students will be aware of the classic 9:3:3:1 ratio, but they can often struggle when other factors such as codominance are included in the question. This resource is ideal stretch and challenge material for more able students once they have mastered the basics of the dihybrid cross. It is also ideal preparation for the more challenging questions on this topic favoured by most exam boards. Keywords: dihybrid, ratio, cross, genetics

This resource consists of two worksheets aimed at advanced biology students or level 3 applied science students. The first worksheet is a simple review of how an electron microscope functions and the key points about magnification, resolution and TEM/SEM (the image is that of a tapeworm head). The second worksheet is a table comparing electron microscopes with light microscopes. Three different web references are given and students are required to use these to complete the table. At the end of the exercise, they should be able to confidently compare and contrast light microscopes with electron microscopes.