HELP PLEASE WITH SCIENCE???

[Redfraggle]

Hi all

Im asking for help rather urgently here. I have to give a presentation on Wednesday evening at a Uni in a lecture theatre about the use of science in the classroom using a microscope. Have any of you done any good 'easy' experiments that I could demonstrate? Or at least have any ideas about some?

Thanks

[eirian]

You could just do looking at a hair, or, I remember looking at skin cells (obtained by running a fingernail over the inside of your cheek and smearing on a slide).

[Bunnylump]

Well, the EASIEST thing to do is to get a set of ready prepared slides from somewhere like Early Learning Centre (not sure if they still do them but they used to years ago - we have a set from yonks ago.)

The next easiest thing to do is to put some cheek cells on a slide and stain them. That shows the cells up nicely. I had a quick google and this looks like it explains what to do pretty straightforwardly...
http://www.mos.org/sln/sem/staining.html

You could also try separating the underneath membranous layer from the bottom of a leaf (you can sometimes just peel it, but you can definitely do it with a scalpel). This will show the stomata (little holes in the bottom of the leaf where water leaves via transpiration and gas exchange takes place).

[MBH]

OK - you're getting sensible suggestions - So......






I think you should hop on the slide yourself and let them all look through the microscope at a Glamorous Fraggle

[Bunnylump]

I just had another thought. Have any of the kids at school got NITS?? They look brilliant under a microscope...


Slightly less yukky idea is to put some daphnia (water fleas) under there in a drop of water. They are transparent and you can clearly see their hearts beating away. Obviously you would have to think of ethical concerns and only put them there for a few seconds, and not let them get hot under the microscope lamp. You can usually get daphnia from aquatic centres and tropical fish shops.

[SparkOut]

if you very carefully peel a thin sliver of the layer of an onion you get a fantastic pattern of the cells, all stacked together like bricks in a wall.

[Bunnylump]

Yes, that is a good one too. In fact, thinking about it, as far as I remember, one of the topics you have to cover in key stage 2 science is the differences and similarities between animal cells and plant cells. How about onion as S/O suggests (you need a REALLY thin layer btw, thinner than tissue paper for it to work best) AND cheek cells? With those two to compare you could certainly see that both of them have nucleii at the very least.

[Redfraggle]

WOW!!! These sound great. I like the idea of the different cells. If I prepare some tomorrow we should be up and running. I have offered to do the talking - what have I done??

BTW Bunny - the girl I work with thought last week that I had headlice because she thought the image on the screen was taken through our webcam which was pointed at my head. I tried to stifle a laugh (which is really hard for me to do) and ended up snorting all over the lecture theatre and I had a mouthful of lucozade which was in serious danger of spurting all over the place (So not professional)

MBH - if you looked at me under a microscope you would need counselling!!!!

[Bunnylump]

That conjures up quite an image! Good luck with it!

[Redfraggle]

This is a nightmare - originally I was going to investigate the spectrum by placing coloured slides under the microscope and then overlapping them to show the different colours but I can't get anything with a strong enough colour which is transparent.

I like the idea of different cells. They have different shapes too don't they?

I could maybe include sugar and salt for cuboids!

[giraffe]

I can't get anything with a strong enough colour which is transparent

Quality street wrappers? or are they made of something else these days?

[Redfraggle]

Tried that - the colour is too weak.

I also tried - coloured counters. Clear perpex and even colouring in a transparent sheet.

[Laura]

I think I've remembered how to do this correctly.

Paint the underneath of a leaf with 1cm square of clear nail varnish. Let it dry, then stick a piece of sellotape over the top and peel off, taking the nail varnish with you. Stick it onto a slide.

Do the same on the top side of a leaf, and compare the number of stomata (the little holes for respiration).

There should be more on the underside, because the plant would lose too much water if they were on the top, because of the direct sunlight.

PLEASE check my terminology. I think it's right, but it's a long time since I did science.

[Bunnylump]

Here's what daphnia look like. You can see their hearts really easily.
http://www.youtube.com/watch?v=MJCnZ0pB3q4

[Redfraggle]

OMG that's brill - but our nearest aquatic shop is 30 miles away - will note for future lessons!

I like the leaf experiment - this is for approx. 7 year olds so it has to be simple.

[Bunnylump]

The onion sliver idea is very straightforward and very effective.

We did an experiment with daphnia where some of them were put in red bull. The difference in heart rates was phenominal!!

[Redfraggle]

I will let you know tomorrow what I have prepared for Wednesday night - OMG they are going to film me for this - I AM A MUPPET!!!

[Bunnylump]

No you're not. You're a FRAGGLE!!

You'll do fine. Just as long as you can reach over the podium.

[MBH]

OMG that's brill - but our nearest aquatic shop is 30 miles away - will note for future lessons!

If you've got big-screen access to the Internet, then you could use a clip like that as a resource to show what could be done.

[giraffe]

Fraggle,I hate speaking in public.I worked for a big Belgian company many years ago and they asked me to trial a new computer system about stock forecasting . I thought it was a load of rubbish, but went with the flow. Then I was asked to go with the Belgian colleague in charge of the project to France to give a speech about it to all the other accountants in the group, in French!

Thank goodness my Belgian colleague was quite happy to do it in English with me, and just answer questions in French. I doubt anyone had a clue what we were on about (I certainly didn't).

Good luck....it could be far worse!