Daphnia-Caffeine experiment alternative

If you are working abroad then it can be a big problem trying to complete the core practicals included in the Edexcel A Level syllabus. At the moment I am having a lot of difficulty obtaining simple bacteria and in the past it has been impossible to get daphnia shipped internationally.
One alternative to using daphnia to observe the effects of caffeine on heart rate is to use mosquito larvae.
My colleague picked this tip up on a recent exam review session in Madrid. He tried it out and found that it was easier to do than with daphnia, both the heart beat could be counted (and it is slower than daphnia)and a large blood vessel could also be observed pulsating. In hot countries it should be fairly easy to get hold of the larvae from any area of still water.

IGCSE Biology: Skin and insulation coursework investigation

Most, if not all exam boards, require students to design, implement and evaluate their own investigations. For Cambridge IGCSE this is assessed by the practical skill C4. A popular coursework experiment for C4 in IGCSE Cambridge is for students to design an practical that models insulation adaptation in animals as there are a wide variety of choices.

Some may compare heat loss between a 100cm3 measuring cylinder (tall and thin or high surface area:volume ratio) and a 100cm3 beaker (short and fat or low surface area to colume ratio). Other students may choose to simulate clothing or fur by adding layers of clothing or wool to test tubes. Investigating huddling with many testubes surrounding one test tube as compared to one lone test tube is also popular as it can always be introduced with the segment from the Life in the Freezer video showing the emperor penguins in the Antarctic.

Another possibility is to investigate the role of fat as an insulating layer in skin. This relates directly to comparing adaptations as well as it is possible to talk about the fat layers laid down by seals etc. This practical simply involves pouring a layer of cooking oil onto the surface of some hot water and comparing the heat loss with a similar beaker of hot water that does not have the oil. I have tried this experiment with both Year 9 and 10 and it works very well. The beauty of this experiment is that the intial simple version can be used as an introduction for studnets to extend it to investigate the effects of different anounts of oil (and perhaps different types). Again I have tried this out and it does show a correlation adding up to 20cm3 of oil in 5 cm3 increments. Unlike many of the experiemnts suggested above this allows students to have a continuous variable to graph and so can be more challenging to analyse whilst being easy to design.

I have added the worksheets below which have the intial introductory practical and the practical design set as homework. It is in Word so is easy to modify. My colleague has used this experiment as a C4 training excersise for the Year 10 students and developed a short checklist to help them write their evaluations. I have added this as well.

Worksheets:

Investigating Skin Structure and Function

Coursework evaluation

Using textbooks: its not what you use but the way you use it!

At the risk of being rant like again (see previous PowerPoint post) I have trouble with the double standards surrounding the use of textbooks in class. I have actually had teachers smugly say that they don’t use textbooks, as if this is some old-fashioned lazy way of teaching that they, the amazing revolutionary inspirational teachers that they are, would not dream of stooping too. Usually these are the same teachers who basically transcribe everything onto worksheets and then shower their students with pieces of paper.

I used to be a little like this until I realised that for a significant proportion of class-time my students were cutting, sticking, looking for or losing pieces of paper. I also noticed that there is a limit to worksheets that students can handle in one lesson and have frequently endured groans as I handed out yet another one.

Don’t get me wrong, I am not anti-worksheet, I use them a lot, but I don’t use them at the expense of a textbook. Basically a textbook, if correctly chosen for the course, should deliver all we need. It should have the required information and additional questions to prompt the reader to assimilate the concepts taught. The key question is not whether we should be untrendy and use them but how we can encourage students to use them correctly.

My key tips are (yes I know, yet another internet top ten tips…and apologies if I am teaching you to suck eggs but it may help NQTs):

1. Use the words in bold in the text and tell the student to list them and make a glossary.

2. Use guided note-taking. This is like a comprehension exercise. Often students, particularly low ability, do not know the difference between key information and explanatory information and simply copy everything down without thinking. I work through the textbook, converting the information into exam like questions. After all I know the syllabus and I know what the exam papers are like so I can tailor the notes/questions to suit. The students then use the worksheets (see told you I use them) to work through the section and pull out the key information and actively think about what they are reading. I call these InfoQuests (as opposed to WebQuests and they are basically a booklet of worksheets) and I have added a couple of these to the IGCSE and AS resources. Very textbook specific though.

3. Students should list page reference numbers in their own notes so they can refer directly back to the relevant page when revising.

4. The book should be defaced by the end of the course! If the students are allowed to keep the books (A level students usually have their own at least) I encourage them to highlight, make pencil notes and add post-it notes throughout. It is a learning tool and should be used. Students who achieve the top grades also usually have books full of post-it notes with questions they need to ask me the next time the see me. I love this method as questions are very specific and the answers are usually short. Much better than the general shrug and “I don’t get photosynthesis”…I mean that is a whole topic!

5. Never give out page numbers but just state the topic heading then encourage them to use the contents and index pages to find the page. This is a great opening activity in itself and also keeps the students familiar with their books. Plus they act less like drones numbly turning to the page number given rather than the topic being studied.

6. Use the keyword technique (they usually hate it but it works). In short they read a short section, listing keywords in the margin as they go (plus scribbling down any diagrams, without labels), close the textbook and then make notes using the keywords as guides, plus label any diagram. This requires a lot of concentration and has to be done in one go (i.e. they can’t really natter to their friends, which is why they hate it). The mental processing this takes is much greater than copying directly and they can be amazed at the quality of notes made without the book being open. Recall is also often improved.

7. Students reading out loud from the book seems to keep many on task. Obviously this shouldn’t drag on and naturally we need to be sensitive as to who we pick to read. The students can then shut the book and work in groups to MindMap the topic just covered. I then get them to show and explain their maps. The learning is almost organic this way but of course I do close with formal notes/handout or presentation (or this could be done first and the textbook activity could be a closing activity).

8. Use the contents page as an outline study guide. My students are always asking me, prior to their end of year exams, for a list of what they should study as “other teachers have given them”. I cheerfully explain they already have some lists, they disagree, I tell them they have, they say they haven’t, I say they have….it’s called their syllabus. They grumble, as this document isn’t the “here is the mark scheme to your exam” quick fix they are really after. So then I tell them they have a simpler summary list. They say the haven’t, I say they have…it’s the contents page of their textbook (to which one student recently replied “what’s that?”…why do I bother?).

9. Advise students not to buy too many study guides etc. and to focus on one or two recommended sources: their textbook and one revision guide. Too many students spend too much time looking through a plethora of books that they hope will magically do their revision for them. They lose focus and end up being busy doing nothing. Less fuss and more focus.

10. Often I will photocopy a diagram from the book, tipex out the labels and hand it back as a worksheet to label. However this just results in mindless copying and doesn’t have any learning quality. To counteract this I will either re-orient the diagram so it is sideways, or upside down (if it is appropriate) or use a slightly different diagram from the internet that they then have to try and match to the books diagram. They really have to pay attention to the structures then (the heart is a classic for this as are the nutrient cycles).

Obviously not every lesson should be all about the book. Like every strategy it is variation that works, integrating fantastic multimedia resources with wonderful practicals and useful worksheets. However I do believe that the book is the backbone to the course, always there, complete, without pages falling out and missing lessons. We should applaud the wonderful textbook and remember that time for some calm focus so students can orientate themselves within a two year course is useful. Following a textbook allows students to know where they have been and know where they are going next. It is easy to flick through, to carry around and can be taken on buses and even into the bathroom (after all bidets are for keeping books in…aren’t they?).

As with all resources and techniques it is not what is used but how it is used, how often and how well integrated with other modes of delivery. So I am making a stand for the textbook! We all use them and should not feel like fuddy duddies for doing so: it is a great resource!

13 rules for teachers to avoid causing Death by Powerpoint

PowerPoint is a tool like a pen or a typewriter…

The big difference between these tools is not the technology involved but the fact that a poor lesson dominated by a long, linear lecture delivered by PowerPoint is often blamed on the tool not the teacher. We do not blame the pen or the typewriter for a badly written book, so we should not dismiss PowerPoint as a very important educational tool because it isn’t used effectively.

To continue my rant for a little longer I will add that the cynical sense of snobbery that exists regarding the use of PowerPoint as an educational tool from the ‘Death by PowerPoint‘ (DBP) brigade usually occurs for one of three reasons:

A) Those that use the DBP problem to dismiss PowerPoint altogether. This is usually by people who are relatively techno-phobic and seize on any excuse not to introduce technology into the classroom.

B) The type of techies who like to keep all the technology a mystery and set themselves up as gurus. You can spot these types because when you ask them a question they will reply in full on jargon that they know you don’t understand (the aim is to show you what they know rather than to actually help you) and always leave a few key steps out so you never quite learn to do something with confidence (and so prevent you also reaching guru status). PowerPoint is a particular threat to them as it is actually very easy to learn and also has a huge hidden array of abilities most of us don’t even know about. Ordinary folk learning effective PowerPoint risks their elite status.

C) Those that actually like technology and want to see it used effectively and correctly so that the crowd in group A can stop whinging, we can take group B down a peg or two and our students have a positive, productive learning experience. This crowd see’s poor PowerPoint use as a threat to the use of technology in class and can often look elsewhere for other approaches.

I belong to the C group (though I do suspect I have my moments when I wander into the B camp) but do think we can run the risk of missing out on a great tool by not treating PowerPoint with the respect it deserves.

Death by PowerPoint does exist. I have fallen foul of it myself many a time. So I have a set of rules if I am designing a PowerPoint presentation to deliver a lesson:

My 13 top tips are:

1) No more than 5 information slides (ie. no interactivity) without an instruction slide prompting a paper-based or practical activity for the students so focus is away from the whiteboard. Of course this varies with the age-group, with Sixth Form I may have one or two more, lower years much less. Adding actual instruction slides prompts change of activity and prevents the teacher from falling in love with their own voice and getting carried away.

This is the key rule designed to prevent Death by PowerPoint.

2) Add a ‘write-on’ activity interactive slide by switching the pointer to a pen within the first 2 or three slides. Good for brainstorming previous knowledge. Obviously this method can be employed throughout and totally plain slides can be used for students to write on. (Right click on screen and you can change pointer format during a show).

3) Inter-mingle information slides with interactive slides with quiz questions, video clip or flash activity to summarise sections: just one or two multiple choice questions, card sort activity etc. or online quiz. This does not affect rule 1, interactive slides don’t count as one of the 5 information slides (but don’t get daft and have a 100 quiz questions).

4) Don’t use a fancy theme or background effects. Themes must not detract from the information or indeed make it difficult to see. Get your font and background contrast right. What is okay on the screen will look different on a white-board.

5) Vary the theme between your presentations slightly so it does not become monotonous for students and each topic has a different ‘feel’. I have even had students vote on the colour theme for the next topic if I am making a new presentation.

6) Use WordArt and sound effects sparingly (if at all). WordArt certainly should not be used as titles for information slides. I hate WordArt!

7) Use relevant images and place near text. Do not use images for the sake of it or to fill up space. Sometimes an image or picture on its own works wonders for discussion and or with brief instruction for an instruction slide (eg. for paper-based activity or role-play).

Either have no slide transition effects or very simple ones unless needed for a single special effect. They do not add to the information. If a transition effect is used throughout the presentation then it should be the same one.

9) Never use more than ten lines of text. Font size usually 24 and Arial or Comic sans (for lower school) is best. No fancy fonts (especially hand-writing ones) and minimise use of all capitals to help dyslexics (and everyone else if we are honest).

10) Don’t bullet point everything. (see image for joke. See! The image is relevant!)

11) Animate slides so information is revealed in stages. This keeps students at your pace. However keep animation relevant to revealing information and use the same one or two throughout. Wipe, appear and fade are often the best (though I have been known to include bouncing peas in a genetics presentation…couldn’t resist). Motion paths should also be smooth. Avoid whooshing in text and spiralling in clipart etc. Keep it simple (that could be added to a lot of the rules).

12) Prepare a student version presentation to provide two slides/page handouts. I often use student versions with incomplete diagrams so that they can label as I work through the teacher version of the presentation. Don’t give out notes pages with full details as pupils switch off as they think they can read them later (alternatively hand them out at the end).

13) Allow the students to know the length and style of the presentation. This isn’t really a rule specific to PowerPoint but is linked to the practice of informing students of their lesson objective and outline. What are they expected to do whilst working through the presentation with you, how long is the topic, how many slides etc. I don’t know why we don’t collaborate more with our students as to how they want their lessons to proceed. A sense of ownership always helps motivation and behaviour (but that is a topic for another day).

Yes I know, I should have done a 10 top tips not a 13 top tips, but at least I have kept the alliteration going (sort of)!

Key concepts: information slides, interactive slides, instruction slides, relevance, simplicity and collaboration.

Any you disagree with or can add? Let me know.