looking for science project ideas

[njitgrad]

My apologies if I am posting this in the wrong forum.

My 4th grade son has two microscopes (an AmScope LED battery operated one and a much older recent-hand-me-down Bausch & Lomb model). My wife and I are in the process of purchasing a still/motion camera for the AmScope so that he can view, capture, and print images (and video) of specimens being examined.

For his upcoming school science project he wishes to investigate and report on something that involves the use of a microscope. Not being that familiar with biology I am looking for suggestions to get him started. His project will need to contain a hypothesis, research, experimentation, and recorded results. All artifacts (pictures, sequences of pictures, graphs, formulas, etc) will need to be glued to a tri-fold board. No props other than the tri-fold are allowed at the science fair. The tri-fold must speak for itself.

My suggestion would be to study the effects of a particular specimen over a period of time when it is exposed to a certain stimulus. The only problem is that I can't think of any time of experiment that would take a prolonged period of observations (approx 5-10 days). I am a software engineer and my experience is limited to electronics and computers.

Any suggestions are welcome!

[zzffnn]

I suggest trying something that is easy and cheap. How about a yeast growing experiment that costs less than $20 and less than 4 hours? Does your experiment have to be long?

Hypothesis:
Yeast cells need optimal temperature and food source to grow optimally to large quantities.

Research and experimentation:
Set up 3 sets of parallel samples that last the same length of time. Each set contains 3 replicates.

Set I: yeast cells cultured in optimal temperature (say 37C, though I am not sure exact temp) and with sugar as food source.

Set II: yeast cells kept in refrigerated (4C) water and without any food source.

Set III: something in between I and II. Maybe half of optimal temperature (13C?) and without sugar.

Then let sets I, II and III grow for the exact same amount of time (use a time that is optimal for set I). Then compare cell numbers from sets I, II and III. You can just take photos and count cell numbers in view (of scope eyepiece/camera), or use a $15 hemocytometer for exact numbers.

I suspect you will see obvious difference and hemocytometer is not needed.

Results will be cell number counts and confirm hypothesis.

To qualify posting in this sub-forum, maybe show us your old Bausch and Lomb scope (we like old scopes in this forum)? Does it have any marking on it? I am semi-joking here, don't take it too seriously.

[gekko]

I was thinking the same kind of thing, but I'm not knowledgeable like zzffnn, so I was googling to see what is there. Here are some links that may be useful:
https://www.google.com/url?sa=t&rct=j&q ... WE&cad=rja
https://kenanfellows.org/kfp-cp-sites/c ... index.html
https://www.youtube.com/watch?v=BTHYaf-EuYs
http://www2.mrc-lmb.cam.ac.uk/microscop ... /yeast.php

[lorez]

One thing you may want to do would be to ask your son what he would like to study. Knowing that would help you research the "hows" of the project.

Fourth grade is a great time for such pursuits... been there, done that. In fact I handed in my project last week.

lorez

[njitgrad]

One thing you may want to do would be to ask your son what he would like to study. Knowing that would help you research the "hows" of the project.

Fourth grade is a great time for such pursuits... been there, done that. In fact I handed in my project last week.

lorez

Anything and everything. We're just in the brainstorming phase. The yeast idea was good but if memory serves there were two kids that did that last year at my older son's science fair. Looking for unique ideas and something that involves days, not just hours of observations

Thank you all so far.

[admin]

Hello,
Long term observation projects are risky, if something goes wrong, then the whole data becomes useless and you wasted a lot of time. For a fourth grade student (primary school), you need a simple experiment that can be repeated easily and one which gives quick results and pictures which are visually impressive.

1. Research question: How does salt concentration influence loss of water of red onion cells (osmosis)?
2. Hypothesis: The higher the salt concentration the faster the loss of water from the red onion cells
3. Method: make different concentrations of salt water (including one without salt, and up to saturation). Place red onion cells on slide, cover glass on top and add salt water from the side of the cover glass (dropper pipette). Take pictures at different times (eg every 30 seconds). Take fresh onion and repeat with different salt concentration. You can take the same onion piece but have to wash it to remove all salt from the previous try. Place the almost dry onion on the slide and then add the salt solution, otherwise the concentration of the salt solution will change.
4. Results: Time needed for the cell to lose all water. This should be fastest for the high salt concentration and should not take place when adding pure water and low salt concentrations. You need a certain critical salt concentration for the cell to lose water and this concentration can also be determined.

You can also try this with sugar instead of table salt. Adding fresh water reverses the process.

An animated GIF can be found here to see what goes on and there is also a link to the magazine with instructions on how to get the red onion cells thin enough:
http://www.microbehunter.com/plasmolysi ... ion-cells/

------

If you want to work with yeast, the CO2 formation can also be observed (bubbles forming). How fast do yeast cells make CO2 dependent on the sugar concentration? Bubbles grow faster when more sugar added. Yeast concentration needs to be high otherwise bubble formation is too slow.

Download this issue of the magazine for some instructions:
http://www.microbehunter.com/microbehun ... -may-2012/

Oliver

[charlie]

\
Now you see why Oliver gets the BIG bucks!

[zzffnn]

What Oliver said.

You need good amount of research subjects that are safe, cheap, reliable and easy. And you do not have much lab resource for it. Short of yeast or dental bacteria, there are not many alternatives.

You can determine what % of alcohol or soap water kills yeast cells. At high %, yeast cells are ruptured and such can be stained with methylene blue and see under microscope. At low %, yeast may tolerate that.

Or take some dental bacteria, before and after teeth brush, then culture in sugar solution and count cell number. Hypothesis is that teeth brushing kills bacteria. Such microscopy observation and counting may not be easy though.

[JimT]

A few more ideas:

He can examine different hair samples; animal - cat/ dog, human; blond, brown, black, gray.

He can grow and examine different kinds of mold; bread mold, cheese mold, fruit molds.

Check out your local library for microscope books for kids as they will have additional ideas.

Let us know what y'all decide and how it works out.

JimT

[zzffnn]

He can examine different hair samples; animal - cat/ dog, human; blond, brown, black, gray

Hypothesis for the hair project may be:
Sheep/dog/cat/rabbit hair is hollow and has more insulating volume, than human skin hair, therefore those animals can live in cold temperature for longer.

I dont know what to do for experiment in that case, without setting up inhumane treatment, though.

Edit: maybe take different fur coats of different insulating ability and measure their temperature-keeping ability. Then show microscopic picture of different fur fiber, the more insulating one being more fluffy and hollow.But coat insulation ability is also related to fiber density (have to make this parameter equal for fair comparison), in additional to individual fiber's insulating ability.

[JimT]

Njitgrad, you haven't said where y'all live and what the climate is like but maybe there are petting zoos, Vets offices, and Humane Society sites you can visit to collect different animal hair samples. In fact, a Vets office might be a great place to start to collect hair from different breeds and I bet the Vet would be happy to help out.

JimT

[zzffnn]

Replicating the following project will win your son first price in science fair, if you manage (it may be difficult even for a biologist though):
http://www.jstor.org/stable/3226006?seq ... b_contents

[njitgrad]

Hello,
Long term observation projects are risky, if something goes wrong, then the whole data becomes useless and you wasted a lot of time. For a fourth grade student (primary school), you need a simple experiment that can be repeated easily and one which gives quick results and pictures which are visually impressive.

1. Research question: How does salt concentration influence loss of water of red onion cells (osmosis)?
2. Hypothesis: The higher the salt concentration the faster the loss of water from the red onion cells
3. Method: make different concentrations of salt water (including one without salt, and up to saturation). Place red onion cells on slide, cover glass on top and add salt water from the side of the cover glass (dropper pipette). Take pictures at different times (eg every 30 seconds). Take fresh onion and repeat with different salt concentration. You can take the same onion piece but have to wash it to remove all salt from the previous try. Place the almost dry onion on the slide and then add the salt solution, otherwise the concentration of the salt solution will change.
4. Results: Time needed for the cell to lose all water. This should be fastest for the high salt concentration and should not take place when adding pure water and low salt concentrations. You need a certain critical salt concentration for the cell to lose water and this concentration can also be determined.

I really like this idea, Thank you. Simple, repeatable and easy to demonstrate. We will do a trial run as soon as the camera attachment comes in and I can get it up and running.

[gekko]

Hello,
Long term observation projects are risky, if something goes wrong, then the whole data becomes useless and you wasted a lot of time. For a fourth grade student (primary school), you need a simple experiment that can be repeated easily and one which gives quick results and pictures which are visually impressive.

1. Research question: How does salt concentration influence loss of water of red onion cells (osmosis)?
2. Hypothesis: The higher the salt concentration the faster the loss of water from the red onion cells
3. Method: make different concentrations of salt water (including one without salt, and up to saturation). Place red onion cells on slide, cover glass on top and add salt water from the side of the cover glass (dropper pipette). Take pictures at different times (eg every 30 seconds). Take fresh onion and repeat with different salt concentration. You can take the same onion piece but have to wash it to remove all salt from the previous try. Place the almost dry onion on the slide and then add the salt solution, otherwise the concentration of the salt solution will change.
4. Results: Time needed for the cell to lose all water. This should be fastest for the high salt concentration and should not take place when adding pure water and low salt concentrations. You need a certain critical salt concentration for the cell to lose water and this concentration can also be determined.

I really like this idea, Thank you. Simple, repeatable and easy to demonstrate. We will do a trial run as soon as the camera attachment comes in and I can get it up and running.

Very wise.

[njitgrad]

You need a certain critical salt concentration for the cell to lose water and this concentration can also be determined.

Can you elaborate on this?

[zzffnn]

You need a certain critical salt concentration for the cell to lose water and this concentration can also be determined.

Can you elaborate on this?

You need to run experiments to determine that critical concentration. For human cells, 0.9% sodium chloride is physiologically neutral (not hyper nor hypotonic) - much higher salt concentration will shrink cells. For plant (opinion) cell, if you cannot find a reference, you would have to find out yourself by looking at cell shrinking

[admin]

Some more information about the onion plasmolysis experiment. This is a common demonstration experiment in schools. The experiment is educationally valuable for several reasons.
1. It shows that the cell itself actually does not shrink. The cell wall of the onion cells do stay the same and no not cave in. This shows that the cell wall is important for maintaining the structure and shape of the cell. It is the cytoplasm with the red pigment that shrinks and separates from the cell wall. The cytoplasm is surrounded by a cell membrane, which is too thin to observe, however.
2. The membrane stays attached to the cell wall at certain places, these are the plasmodesmata and they serve for cell to cell communication.
https://en.wikipedia.org/wiki/Plasmodesma
3. You can see that the red pigment is not sucked out of the cell. This illustrates that the cell membrane is indeed semi-permeable. Water is able to leave but not the red pigment.
4. As water is drawn out of the cell the pigment inside the cell becomes more concentrated and thus darker.
5. On some places it is also possible to see that not the whole cell content is filled with red pigment. Especially at the regions of the plasmodesmata, there are clear regions. These regions are most likely the cytoplasm, while the red pigment can be found inside the large vacuole.

https://en.wikipedia.org/wiki/Onion_epidermal_cell

Oliver.

[njitgrad]

Some more information about the onion plasmolysis experiment. This is a common demonstration experiment in schools. The experiment is educationally valuable for several reasons.
1. It shows that the cell itself actually does not shrink. The cell wall of the onion cells do stay the same and no not cave in. This shows that the cell wall is important for maintaining the structure and shape of the cell. It is the cytoplasm with the red pigment that shrinks and separates from the cell wall. The cytoplasm is surrounded by a cell membrane, which is too thin to observe, however.
2. The membrane stays attached to the cell wall at certain places, these are the plasmodesmata and they serve for cell to cell communication.
https://en.wikipedia.org/wiki/Plasmodesma
3. You can see that the red pigment is not sucked out of the cell. This illustrates that the cell membrane is indeed semi-permeable. Water is able to leave but not the red pigment.
4. As water is drawn out of the cell the pigment inside the cell becomes more concentrated and thus darker.
5. On some places it is also possible to see that not the whole cell content is filled with red pigment. Especially at the regions of the plasmodesmata, there are clear regions. These regions are most likely the cytoplasm, while the red pigment can be found inside the large vacuole.

https://en.wikipedia.org/wiki/Onion_epidermal_cell

Oliver.

More great info. I'm sure I will check back in a few days from now with some results.

[njitgrad]

Hello,
Long term observation projects are risky, if something goes wrong, then the whole data becomes useless and you wasted a lot of time. For a fourth grade student (primary school), you need a simple experiment that can be repeated easily and one which gives quick results and pictures which are visually impressive.

1. Research question: How does salt concentration influence loss of water of red onion cells (osmosis)?
2. Hypothesis: The higher the salt concentration the faster the loss of water from the red onion cells
3. Method: make different concentrations of salt water (including one without salt, and up to saturation). Place red onion cells on slide, cover glass on top and add salt water from the side of the cover glass (dropper pipette). Take pictures at different times (eg every 30 seconds). Take fresh onion and repeat with different salt concentration. You can take the same onion piece but have to wash it to remove all salt from the previous try. Place the almost dry onion on the slide and then add the salt solution, otherwise the concentration of the salt solution will change.
4. Results: Time needed for the cell to lose all water. This should be fastest for the high salt concentration and should not take place when adding pure water and low salt concentrations. You need a certain critical salt concentration for the cell to lose water and this concentration can also be determined.

Rougly speaking, what volume of water --to-- what amount(s) of salt are we talking here? Suppose I were to make 5 different samples to keep it simple: no salt added, 25% salt solution, 50% salt solution, 75% salt solution, and 100% salt solution.

[Oliver]

Rougly speaking, what volume of water --to-- what amount(s) of salt are we talking here? Suppose I were to make 5 different samples to keep it simple: no salt added, 25% salt solution, 50% salt solution, 75% salt solution, and 100% salt solution.

Wikipedia: At 20 °C one milliliter of water can dissolve about 0.357 grams of salt; a concentration of 26.3%.
(This will be our 100% saturation.)

%: of max saturation
g: g NaCl per ml

0% - 0,000g
25% - 0,089g
50% - 0,179g
75% - 0,268g
100% - 0,357g

Oliver

[njitgrad]

Rougly speaking, what volume of water --to-- what amount(s) of salt are we talking here? Suppose I were to make 5 different samples to keep it simple: no salt added, 25% salt solution, 50% salt solution, 75% salt solution, and 100% salt solution.

Wikipedia: At 20 °C one milliliter of water can dissolve about 0.357 grams of salt; a concentration of 26.3%.
(This will be our 100% saturation.)

%: of max saturation
g: g NaCl per ml

0% - 0,000g
25% - 0,089g
50% - 0,179g
75% - 0,268g
100% - 0,357g

Oliver

Thank you once again... the next question I have is how to measure these quantities of salt and water without instruments....can you recommend a simplified approach that uses fractions of teaspoons perhaps? If not can you recommend inexpensive instruments (I can purchase online in the US) to measure the desired quantities?

[Oliver]

You do not need a scale to measure the amount of salt, or any other expensive equipment. You do need a graduated cylinder to measure the volume of water. This is all.
1. Make a saturated NaCl solution, let's say 300ml. This will give you a bit more than you need. The water should be room temperature (20°C). Add plenty of salt and stir well. If no more salt dissolves (collects at the bottom), then you know that it is saturated. You then know that this is the 100% solution and that it contains 0.357g/ml. Allow the salt to settle and carefully pour off the salt solution, so that any remaining salt crystals stay on the bottom. This is pretty important. You can also pass it through a filter (coffee filter). You know that it is free of crystals, if the liquid is totally clear. It is is not clear, then it could also be tiny air bubbles and then you have to wait for them to disappear. If there are still crystals left, then they will result in the wrong concentration in the subsequent steps.
3. Pure water, no salt, to give you the 0% solution.
2. Take 25ml of the 100% salt stock solution and add 75ml water. This gives you the 25% solution. The total volume is 100ml.
3. Take 50ml of the 100% salt stock solution and add 50ml water. This gives you the 50% solution. The total volume is 100ml.
4. Repeat for the other %, all the way up to 100%.

Alternatively you can use dropper pipettes: 1 drop of salt solution + 9 drops of water to produce a 10% solution etc.

I think that even the 25% solution will result in strong plasmolysis of the cells. Try also concentrations of less than a percent of salt.

This is what I found, but you can choose whatever you like. Plastic graduated cylinders are cheap, but do not measure out organic solvents with them (what you do not intend to do anyway for this experiment).
http://www.amazon.com/Piece-Set-Graduat ... d+cylinder

If you want to keep it cheap, you can use regular coffee cups for mixing. Table salt is not dangerous, therefore residues on the cup are not a problem.

Oliver.

[billbillt]

Hi,
Here is a link for a cheap gram scale on Ebay..

http://www.ebay.com/sch/i.html?_from=R4 ... 5573.m1684

BillT

[njitgrad]

3. Pure water, no salt, to give you the 0% solution.
2. Take 25ml of the 100% salt stock solution and add 75ml water. This gives you the 25% solution. The total volume is 100ml.
3. Take 50ml of the 100% salt stock solution and add 50ml water. This gives you the 50% solution. The total volume is 100ml.
4. Repeat for the other %, all the way up to 100%.

Perfect. I had a feeling there were alternative ways.

[njitgrad]

This is what I found, but you can choose whatever you like. Plastic graduated cylinders are cheap, but do not measure out organic solvents with them (what you do not intend to do anyway for this experiment).
http://www.amazon.com/Piece-Set-Graduat ... d+cylinder
Oliver.

What do you think of this one (a four piece set)?
http://www.amazon.com/Kalevel-Graduated ... lastic+set

[Oliver]

What do you think of this one (a four piece set)?
http://www.amazon.com/Kalevel-Graduated ... lastic+set

Also fine. The one that I showed was simply the one that I found first. They are all lab quality. Plastic is good enough for water and other water-based solutions. Do not use for stains etc. as it might color the plastic. Plastic does not break easily, which is also an advantage.

Oliver.

[njitgrad]

We started experimenting today and had some success. It was not pretty (the procedure part of it) but we saw plasmolysis occuring. The before/after screen captures are in the next post in this thread. We were able to reverse the process as well.

The following is a list of issues we encountered....

1) After trying to slice off a thin piece of red onion skin with an exacto knife, I realized the best way to get a thin specimen was to just peel the onion directly until I got a sample that contained just the thin red layer. After doing that I used precision scissors to cut a small (approx 1 cm x 1 cm) patch.

2) After placing a drop of water on the slide, placing the specimen on it, and then placing the cover slip on, I realized three things...lots of air bubbles, the water was not uniformly distributed resulting in voids, and the slide itself was not lying very flat on the glass slide so it slid as I tried to squeeze out the air bubbles and distribute the water.

3) I added more water droplets on the side of the slide until it appeared all the voids were filled. I then had to sop up the excess. Not exactly what I envisioned.

4) In the first screen shot below, you can actually see the air bubbles so I was never able to get rid of them.

5) I did not have a thermometer (to measure temperature for water at room temp) so I took tepid water from the tap and added and arbitrary amount of salt. Need to get a thermometer!

6) As I drew the salt water across the slide, the slip cover once again gave me an issue. So my before/after shots were not of the identical part of the specimen.

7) When we tried to reverse the process, I had a hard time drawing unsalted water through the specimen under the slip cover. I had to remove the slip cover and apply the water directly. Again, messy procedure, but when I did that, boy did it look cool to see how rapidly the cyptoplasm expanded in the cell walls. It only took a few seconds to occur.

Any suggestions to help with me with my issues working with the cover slip, drawing the water, etc are appreciated.

The next step for us is to (once we iron out the kinks) measure the time plasmolysis takes for different salinities of water. The question I have here is when do you know to stop the timer? When shrinkage is no longer detected? Or when plasmolysis actually starts?

[njitgrad]

The before/after images...

[zzffnn]

What objective lens did you use for those "160x" photos? 16x objective and 10x eyepiece? For 16x objective and when high resolution is not required (your application does not need that much resolution), you do not need cover slip.

[billbillt]

I think these turned out very well!..
BillT