Using immobilised beads of algae to investigate the rate of photosynthesis.

This is a neat idea to immobilise algae in alginate beads and use them to investigate photosynthesis rate. The concentration of carbon dioxide in the solution can be measured using a data logger or an indicator like bicarbonate indicator can be used. This will work best if used in conjunction with a colorimeter.  A range of factors could be tested including temperature, light intensity,frequency of light. Steps must be taken to control variables or to monitor variables which are impossible to control.

Antibacterial properties of a food or food ingredient.

There are many possible investigations here, from mint to chili. controlling the conditions of growth of the bacteria and ensuring save sterile technique are some of the problems. Actually measuring zones of inhibition is quite easy but preparation of a range of concentrations of the food ingredient may prove difficult to organise. If it was possible to quantify and identify the active ingredient then there is more chance of success. Finding a mechanism of action is another desirable outcome, but a study which simply identifies a correlation or a lack of one, without a mechanism, will also be acceptable for an IA.

The affect of temperature on non-enzyme controlled reactions or processes.

This is an interesting twist on an classic enzyme reaction.  What is the effect of temperature on the absorbance of light by photosynthetic pigments?  Is there a difference in the stretchiness of a ring of artery at different temperatures. Of course the control of all the other variables which may affect the reaction will be important and may not be easy.  You have to collect sufficient data and repeats of each value a,d it would be good to be able to suggest a possible biological mechanism, although this isn't essential.

Ripeness of fruit and vitamin C content.

Does ascorbic acid get converted to sugar as part of the ripening process of a fruit.  The challenge of this IA would be to accurately, or quantitatively estimate the ripeness of the fruit.  This could be helped if the fruit can actually be collected as it falls off the tree. Perhaps the colour of the fruit can suggest ripeness, and remember that many plant parts contain vitamin C, not just oranges. DCPIP will be useful as an indicator of the concentration of vit C but a calibration curve might be useful.

Effects of light on vitamin C.

This investigation is interesting as it relates to the shelf life of food and also the quality of food after the processing.  If a bottle of juice is stored in direct sunlight does the vitamin C get damaged.  Using DCPIP and a simple titration an experiment can be planned to estimate the concentration of vitamin C in a juice drink after a range of different light treatments.  Artificial bulbs or sunlight screens could be used to get a range of the independent variable, and of course it will be important to control other variables.
[There are many possible variations on this experiment: such as looking at storage temperature, or interactions with other chemicals, preservatives, colourings, or perhaps even other fruit juices which may cause oxidation or decomposition of Vitamin C., Even simple contact with the air may have an effect. It might also be possible to compare the stability of different sources of vitamin C at different temperatures.  Why limit yourself to vitamin C, any nutrient which can be tested would lend itself to this type of study.  It would be possible to estimate the concentration of enzymes like catalase in samples of fruit, for example.]

Photosynthesis and light colours.

This study as an IA could attempt to answer the following type of research questions, "Given that the absorption spectrum of chlorophyll has peaks at blue and red, can a while light be replaced by a blue and red light and still give the same amount of photosynthesis?"  Of course there are many alternatives, but by trying to answer a precise question like this the planning can be a little simpler. Having said that of course it is important the the background of the exploration section includes appropriate reference to biology theory. There are many ways to measure the rate of photosynthesis, using data logging probes, little clips of spinach leaves, Elodea, and more. This can make for a wide range of choices in the planning of the experiment.  Every experiment will need careful consideration of the controlled variables too.

Methods of preventing decay in vegetables

This is an applied study of inhibition of enzyme reactions, or the prevention of the growth of spoiling bacteria.  It is vital to decide which one of these is the focus of the research question, at the beginning. The way in which bacteria might spoil food could be influenced by the origins of the food, it's cultivation, organic or not, and any treatment after harvesting, or during transport. Controlling these factors will be a challenge but might be possible by washing in diluted antiseptic solution.  Of cause all the normal problems of control of temperature and other factors during the experiment will be important too.  There are lots of possible research questions, and using a single type of vegetable will be more focused than comparing several.

If enzyme reactions are thought to cause the decay this will make for another research pathway. Of course reactions will happen more slowly at cold temperatures, but there may be inhibitors or catalysts in the environment such as plant hormones, acids or oxygen.  Perhaps the enzymes of one fruit (like bananas) will have an effect on another, we all know that storage of bananas and unripe Kiwis can speed up ripening but do they speed up spoiling?

The role of stomata in controlling transpiration rates - using a microscope

Why not use a microscope to investigate a biological process like transpiration? Of course factors which influence the rate of transpiration such as temperature and humidity will need to be controlled if the rate of transpiration is the dependent variable and stomata 'openness' or 'size' is the independent variable but there are other possibilities.  It might be possible to sample leaves in different parts of a plant, so the independent variable is the position on the plant.  Leaves in sunshine, or shade, leaves on a plant which is gradually experiencing more water stress, leaves in rapidly moving air (like on a windy day) compared to slower moving air.  Painting nail varnish onto the leaves may be a good solution, but there are clip on telephone microscopes which could snap a photo in which stomata would be visible.

The effects of playing the flute on asthma, studied using a peak flow meter.

Miller and Goss (in 2013) published an interesting paper which explored physiological responses to playing the American flute. In their methods they show that listening to the music has little effect, but in the conclusions they suggest that beneficial effects of playing a wind instrument are worthy of further study.  This would be a very nice starting point for an individual investigation, especially for a student who plays a wind instrument. One suggestion is that playing the flute may help people with asthma and it is quite easy to measure peak flow in the lab using a spirometer or a simple peak flow meter.
 

Testing enzyme activity in the presence of a suspected inhibitor.

This is a simple twist on a standard enzyme experiment. Students should be able to design an experiment to collect data testing the idea that X inhibitor (eg. a heavy metal or ethanol) either does or doesn't inhibit an enzyme.  If the experiment is designed carefully it may be possible to decide whether the inhibition is reversible or not, and / or if the inhibitor is competitive or non-competitive. Of course the usual controls of the other variables which affect enzymes will be needed.  It would also be helpful to test if the indicator is affected by the suspected enzyme inhibitor, if there is one.

Investigation of a factor which might affect skin temperature.

This seems like an easy investigation but it certainly has challenges. Careful organise for the collection of meaningful data and controlling variables other than the IV will be required. Consent forms for participants are essential and some biological reasoning for the possibility of a correlation will be important.  Possible specific research questions could address temperatures of different parts of the skin, related to hair, or muscle, or blood circulation. alternatively differences between different people, some have cold hands and feet for example.

Data based investigation of animal diseases

In many countries the occurrence of diseases in farm animals or fisheries is recorded by a national agricultural service. At the same time there are possible causes of the spread of disease, or animal susceptibility to infections. For example, migratory birds could spread disease to free range chicken farms, rainfall could affect the spread of a disease, perhaps the location of the farmers market, or other factors affecting contact between cattle. Climate data, or geographical location of different farms could be used to test for correlations.  In this type of study it is important to be selective about the data and to try to control other variables, for example the size of farms, the breed of animals, etc.

The effect of an abiotic factor on a single feature of leaf structure

This is an interesting opportunity to investigate form and function in the leaves of plants. There are several features of plant leaves which are easy to see with the naked eye, such as shape and colour. Other features require some kind of measuring tool, for example a colorimeter for pigment composition, or for measuring thickness.  There are also features which may be interesting to study with a microscope for example, stomata density, the shape of pallisade mesophyll cells, the presence or absence of hairs, or the density of hairs on different parts of the leaf might be interesting.  Abiotic factors could be identified and the sites of leaf sampling could be carefully chosen to incorporate control of variables. While this might be difficult there is a lot which can be considered such as amount of water in the soil, light levels, wind speed, etc.

The effect of aphids on a single aspect of plant structure.

Beans and roses grown in a garden often suffer from the presence of aphids.  In my garden the aphids are sometimes actually cultivated by ants. Does this herbivory affect any structures on the plant leaves. Do the leaves respond to the presence of the aphids?  For example could there be an increase in the thickness of epithelial cells in the leaf, could there be an increase in the density of hairs on the veins of the leaf, alternatively could the presence of leaf hairs on the veins affect the distribution of aphids on the leaves?  There are plenty of options in this kind of study but it could only be carried out during the summer / autumn season when leaves have had time to respond.

The effects of aquatic plants on the nitrate content of water.

We know that plants take up nitrates from their roots by diffusion or active transport and that ecological swimming pools can be constructed using plants and gravel instead of filters. However, in high nitrate water the algae can bloom and cause eutrophication. Would other plants cause eutrophication at high nitrate levels, or is it the fact the algae reduce light penetration in the water and thus lead to the death of some of the algae and the growth of bacteria which causes eutrophication?  This topic is a rich source of research questions and it is quite easy to test the nitrate (and other ion) content of water. What about experimenting with lettuce plants in a hydroponics system or in a school aquarium?
 

Other microscope ideas  - 

leaf structure, relative depth of palisade cells, or number of layers of palisade cells in ivy from different locations,

petals insect navigation and pollination,

human skin suppleness and wrinkles,

root hair distribution in germinating seeds, or garlic roots,

ecological changes in microscopic organisms in a hay infusion,

cytoplasmic streaming in Elodea chloroplasts under different light intensities.

Note: I must look at some of the microscope sites for more ideas.

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