IB Docs (2) Team
IA Experiments that could be done at home
Many teachers have adapted rapidly since January 2020 to find ways to help IB Biology students to continue learning while they stay at home. This poses particular problems with the IA because access to the lab and the usual equipment might be very limited. There is one element of the IA which confinement cannot prevent which is its independent nature. It may be easier for students to concentrate on an investigation without all the problems of moving classrooms and putting away equipment. This page attempts to gather ideas for investigations which could be carried out by a student at home as an IA supervised by their teacher using online communication tools, and possibly supported by the load of some simple lab equipment.
To develop any one of these ideas into an IA students will have to research the topic, decide on their own focused research question and then plan their own method. This ideas might help to get everyone started.
Testing spoilage of milk in different conditions.
Lactobacilli reproduction and growth is part of the cause of milk spoilage. There are other species of bacteria and fungi also involved. What effect do conditions, such as temperature, sunlight have on the rate of spoilage. This is a nice wet laboratory project and there are some simple ways to measure the growth of the bacteria but these can be fiddly to work out, and concentrations of bacteria used in inoculations will need working out.
Testing differences between different preservation processes in milk or other foods.
This is similar to the first idea, about milk spoilage, but this looks at the production processes rather than the storage. Milk can be pasteurised or steralised in several different ways. The study could be adapted for other foods, some are chemically treated after harvest, so washing them will remove the preservative, others are sealed in plastic bags of 'modified atmosphere', which could be left closed or opened, Some are harvested at just the right time so the sugar content or their natural acidity helps to preserve them. With a little research there are a range of potential treatments which could form a topic of study.
Measuring changes to the concentration of vitamin C in foods as they are cooked or stored.
It is possible to measure the concentration of vitamin C in food using simple chemicals (cornflour and iodine) and equipment you might have in the house ( Eye dropper or pipette / syringe, balance). There is a very clear explanation of this in the Wiki How website. Many types of food contain vitamin C and it is thought to be affected by light and certainly by the heat of cooking. It is an important part of the human diet as humans, unlike many other mammals, cannot synthesise this vitamin. Simple questions could be explored, for example the effect of canning on vitamin C concentration, or the different effects of alternative cooking methods, or storage options, e.g. in the fridge, freezer, dried or preserved in pickle or jam.
Examining the glucose concentration in something
using potassium permanganate and heating, from a protocol from Science & plants for schools. This is an interesting quantitative method to estimate glucose concentration. It could be used in a wide range of labs. Lots of plant ideas in the questions and answers It is also possible to use this method to study glucose levels in ripening fruit, lactase activity in milk producing glucose or maltase activity in germinating seeds.
What happens after the sell-by date on yoghurt, and other dairy foods?
A simple question in appearance but quite a complex problem. The first aspect to decide would be for which reason are the products past their best. It could be growth of spoilage bacteria, release of enzymes naturally part of a ripening process, chemical changes from another cause. Of course a specific research question would be needed, but this would probably arise out the choice of food and the background research quite naturally.
The effect of temperature/light/plastic bag on the ripening of fruit, e.g. bananas, cherries, tomatoes.
The challenge is really how to control the temperature of the fruit (or the light) for a long period of time, perhaps 2 weeks. Another difficulty will be to devise a way to measure the extent of fruit ripening, or softness. Bananas lend themselves to this because their skin changes colour. Of course the underlying processes are controlled by enzymes, or the fruit ripening hormone ether.
Investigation of the properties of photosynthetic pigments using different types of olive oil, simple solvent mixes and chromatography with rf values.
Extracting pigments from leaves using solvents used in painting at home might be possible with the correct supervision. Turpentine (a nonpolar solvent) and propanone (a polar solvent) may work in different proportions. Some suggestions of research questions may be; Is there a difference in the composition of photosynthetic pigments in the leaves of a plant found in the sun or the shade? Which pigments are made first in a growing leaf, or are all the pigments made at the same time? How does the shade of a leaf relate to the composition of photosynthetic pigments it contains? Are there more of the non-polar pigments in cold pressed olive oil or are there more polar pigments?
Investigation of SA:vol on the rate of diffusion
This is a standard lab and the challenge will be to ensure that it is put into an interesting biological context. Starting with a process which requires diffusion in living cells will help the topic to be interesting and will show some personal engagement. The analysis of the results and the design of the method is another place where PE can be demonstrated, try to take the standard lab and adapt it so show something which is not 'standard'.
Investigating the effect of sucrose concentration of the rate of respiration in yeast.
This is interesting because the higher concentrations will cause outward osmosis in the yeast and perhaps slow down respiration, or even kill the yeast. Lower concentrations will slow respiration because of a lack of substrate. The challenge will be in deciding which concentrations to test and in explaining the results. It's possible to measure the rate of yeast respiration by watching bread rise, watching gas collect in a balloon or a sealable plastic bag.
Investigating a property of water, one which affects living things.
It could be very interesting to research how the properties of water might behave in different biological systems. For example the capillary effect is thought to help mosses to absorb water from the environment, remember they don't have any vascular tissue. Pond skaters are insects which manage to walk on water using surface tension. Surface tension allows diving beetles to take a bubble of air with them deep into the water when they swim. The presence of detergents is well known to cause algal blooms because of the change in phosphate levels, but could the presence of detergent affect insects, walking on water or breathing? Perhaps the presence of dissolved salts or the pH of water will affect hydrogen bonding, and change its properties.
The effect of body position on heart rate and blood pressure.
The baroreceptor reflex helps to maintain blood pressure at nearly constant levels. The 'baro-reflex' uses negative feedback, an increase in blood pressure causes the heart rate to decrease and also causes blood pressure to decrease. Could the position of the body affect blood pressure and thus heart rate? This might make an interesting investigation. Of course controlling other factors which are well known to affect heart rate will be one of the challenges of an investigation into this topic.
Testing the effectiveness of a shampoo, anti-tangle product or conditioner on a property of hair.
There are many claims made from producers of hair products which could be tested in an IA. Does conditioner really make your hair stronger, does a tangle easing product really prevent knots, or reduce friction between hairs? While it is not permitted to use body fluids in IAs, testing your own hair would be acceptable. To meet the animal experimentation guidelines the hair would have to be collected ethically, without causing pain! Research into the structure of hair and use of a microscope to study changes in the hairs might also be a useful part of this experiment.
Investigation of Age and reaction speed
This is an investigation to test a hypothesis that reaction time wll slow down with age. By testing people of different ages to see if there is a difference in their reaction time it may seem like a simple study, but there are a lot of factors which need to be controlled and it will be difficult to find enough participants to create a large enough data set. There are also many factors to consider in the type of reaction speed test that is used and there are also problems associated with the learning of the skill during the experiment.
Testing the accuracy of colour vision using online colour tests
There are some quite nice online tests of colour vision, and also many telephone apps. This investigation is Design an experiment to investigate a factor which affects the precision of colour vision, age, tiredness, gender, eye colour, etc. http://www.xrite.com/online-color-test-challenge. The challenge will be including Biological theory to explain why your dependent variable is changed by the independent variable.
What is the difference in the CO2 levels in exhaled air before and after exercise?
This investigation might sound simple at a first glance but there are many difficulties to overcome in terms of controlled variables and the method of measuring the CO2. This might involve the use of a data logger, or perhaps a titration using bromothymol blue. The release of CO2 by the body in the lungs is not simple either, factors to consider include the relative amounts of aerobic and anaerobic respiration, as well as the position of the muscles being exercised. Perhaps the muscles with a greater blood flow will cause a different effect to those in the bodies extremities, and what effect could warming up have on the process?
The effect of a short burst of exercise on blood pressure or two groups of people.
This is a simple experiment to carry out, but a difficult experiment to get good controlled data for. There needs to be some clear links to the biology of blood pressure and how exercise affects it. A clear RQ is essential and there are quite a few possibilities. Controlling factors which can affect blood pressure could be an investigation in itself! Of course the IB guidelines on experimentation needs to be followed and written consent sought for participants.
The effect of a warm up on the maximum heart rate (or maximum speed) achieved in a standard test
The role of a warm up in sport is clear. Athletes perform better if they warm up properly before an event. Is there an optimum intensity of warm up to achieve best performance? Can the max performance be measured best using max heart rate or maximum speed? These are just some of the questions which will need answering.
The effect of isotonic drinks on rehydration and recovery after exercise
The problem of this investigation is that it is difficult to measure rehydration or salinity. At the end of a long endurance event cramps and muscle fatigue will be evident but this is not possible to recreate in the lab in school. Perhaps some form of experiment using isotonic solutions on slightly dehydrated muscle tissue from a chicken leg, or liver would work. This would be a challenge and it would require some research before beginning. Avoid any investigation where you are getting friends to drink Gatorade and measuring some unrelated but easy to measure factor, like pulse rate.
Investigation into the effect of regular exercise on the increase in pulse rate after a short period of exercise.
This is a bit more complex than a simple pulse rate investigation, but the challenge to control variables is equally great. If a person exercises regularly they should have a better level of fitness, this might mean that their heart rate increases by less in the short burst of exercise than someone who does no regular exercise.
Examining a factor which affects vital capacity, or tidal capacity of the lungs.
The greatest challenge in this investigation is getting a large enough data set which takes into consideration enough of the factors which need to be controlled. Comparing a factors about the body with tidal capacity and look for a correlation. One nice idea might be to see if the growth in the lungs' vital capacity correlates better with the circumference of the skull or the length of the legs in children of different ages. Biological explanations could look at the way we grow, and if the brain changes size at the same rate as the lungs. It may even be possible to find a database of measurements of children of different ages. There are some ethical questions involved too, and parental consent will be essential for any experiments on children.
The effect of exam conditions on a physiological feature of the body.
In this investigation a change in a physiological feature is explored. There are plenty of factors to control which makes this investigation difficult and if there isn't enough data or the controls are not in place this could lead to a low mark after much work. The choice of physiological features of the body could include heart rate, or pupil size, or skin redness. Measuring theses factors might be tricky and will involve some testing, although using a phone camera or a video camera could help. It is possible to establish a theoretical link between mild stress and adrenaline (epinephrine) which will affect features in the body including pupil size but it is not possible to directly measure the level of any hormones in the body. Remember any participants will need to give written consent before any experimenting, and the mild stress of exam conditions must be harmless.
Examining the relationship between cases of a disease and weather patterns.
This investigation tries to establish a pattern between the weather and the spread of a disease. Using nationally published data on epidemiology and weather data is certainly possible and it could happen that there are correlations between climate and some disease outbreaks this will need explaining in terms of the mechanisms of transmission of the specific disease. Some diseases spread through direct contact, others are transmitted by an insect vector.
Using published epidemiological data to examine a link between an illness and a specific factor.
Here the challenge is the exploration section. You have to show that the data has been carefully selected, and that measures have been taken to ensure that other factors which might affect the data have been controlled, by careful selection of the data used. Some assessment of the reliability of the sources will be needed and some discussion of ethics of using someone's data, with their consent, hopefully. The best investigations will have a biological reason why there might be a correlation between the IV and the DV. The data must be analysed by the student and tables / graphs etc. should include all the normal conventions of d.p. and uncertainties.
Data analysis of body temperature in different groups of people.
If you can find a good data base which provides enough data so that you can choose a part of it (and thus control some variables) it could make a good IA. A hybrid IA could compare experimental data with a data set published in the biological literature. Here is a nice example of a set of data, Body temperature data and there are many more suggestions of data sets here: Temperature of a Healthy Human. An interesting option might be to test whether temperatures of a group of people in your school community measured in an experiment are the same as data selected from one of these data sets. Notice that there are interesting differences in 'oral' and 'tympanic' measurements as well as young and old people, males and females, and who knows more. There are plenty of options to investigate; BMI and temperature, mealtimes, time of day, etc.
Evaluation of habitat diversity or population change using data from fish markets
If there is data available from a local fishing port or the fish market it is likely that the presence and absence of each species at different times can be analysed. Most countries record catch size and monitor fish landings. The OECD has a huge database of global fish landings, this State of Maine - historical fisheries landing data shows one example of locally available data, the NOAA Fisheries database has an enormous amount of data as does the EU fishery statistics database.
The research question could look at the effect of a policy change on habitat diversity, the long term changes in diversity in fish catches, or the evolution of an individual population. It is important to consider all the factors biological and economic which might result in changes in a population. Controlling these factors will be one of the challenges and by explaining why some data had been omitted from the study, and why other data had been retained students will be able to show consideration of controlled variables. The data may lend itself to analysis using a diversity index, useful for comparing several places or different moments in time.
The effects of antibiotics on the germination of seeds or the growth of plants -
This looks like an interesting topic of study. Many methods are possible, and there has been some very recent research suggesting that antibiotics can affect the growth of seeds and plants.
ref P.W. Brian and also Louis G. Nickell and Alexander C. Finlay in the Journal of agricultural and Food chemistry, 2015
Investigation of the behaviour of two groups of animals, or several groups of animals in a range of conditions.
This investigation is going to require a very precise research question and some careful methodology to ensure that the data collected can be used to answer the RQ. However it could be really interesting to compare simple behaviour in animals. Does the behaviour of an animal change as the population increases? Do individuals of different types all behave in the same way in response to a stimulus.
Do plants grow faster in soil which has more microbial activity (respiration)
This investigation could be a nice way to combine two standard procedures, one to estimate the rate of respiration in the soil and another to estimate the rate of growth of a plant. Soil respiration can be measured using a CO2 probe and a data logger the same equipment could be used to measure the rate of photosynthesis, although growth (or photosynthesis) can be measured in other ways too. There are lots of practical problems to overcome, most importantly how to change the soil so that it has different amounts of respiration. One idea would be to make a series of soils using active compost and sand. it might even be possible to use mesocosms to perform this investigation as these would make it easier to control more of the other variables.
The effect of a pet on the diversity or growth rate of plants in a garden lawn.
This is a nice idea for an investigation into the number of species found in a garden in houses where there are pets and no pets. Ecological techniques and quadrat sampling could be used together with mapping of digging or scratching to establish whether the presence of a pet increases plant diversity or not. There are many possible variations, perhaps the presence of animal excrement could be the causal factor, otherwise some species may be more resistant to scratching and disturbance, caged animals can selectively graze on parts of a lawn, just to mention a few ideas.
Flowering stages of a plant at different altitudes
The climate is different at different altitudes and the growing season begins later at high altitude. This investigation relies on the recording of abiotic data and also data about the stage of the flowering cycle. A method could use the number of flowers / fruit / buds etc in a single species at different altitudes up a mountain. Of course there will be other factors to consider, for example local features of the habitat, soil type, depth, wetness, where the plants are growing and the aspect of the flowers' location, not to mention grazing and grass cutting.
The effect of river pollution on the presence of a single species
It is quite easy to record the number of individual plants / animals of a single species in a river at different distances above and below a possible source of pollution. If a relevant abiotic factor in the water can also be recorded indicating the pollution level, eg pH, nitrate level, BOD, turbidity etc. then this could be a very good study.
How does a specific abiotic factor affect biodiversity in a habitat?
This is nice project if there is a specific environmental gradient in the site being investigated. The use of a transect of transects will be useful for the sampling. The challenge is to explain why there might be a change using biology and then to test it using some type of ecological sampling. Ensuring that there is enough data will also be important as there are likely to be quite a few other factors which will need controlling or considering at least.
The effect of different colours of light on the growth of seedlings
This is an interesting study and it links to the role of auxin as well as photosynthesis so there is theory to discuss. Practical procedures and controls will be the challenge, but data should be easy to record if the seedlings grow. Some preparation time will be required to germinate and plant the seeds.
The effect of salt on the germination of seeds.
This is an interesting topic of investigation which relates to osmosis and ecology. Some plants grow well in coastal soils with igh salt concentrations but others don't. The practical methods to germinate seeds and select appropriate salt concentrations will present definite challenges but this is an interesting study for students living near the coast, or in places where salt is applied to the roads in winter.
Examining the effect of plants on nitrates/nitrites/ammonia in the runoff from soils
While there is a considerable challenge in designing apparatus and growing plants the idea of using plants to filter the water in 'ecological' swimming pools or an "eco-aquarium" is quite well established. There may be a combination of roles for plant roots and bacteria in the substrate and both of these link to the nitrogen cycle and so would allow for a detailed hypothesis and a focused research question. The type of substrate may also make a difference.
The effect of soil pH on the germination of seeds
This is a simple idea, but the explanation is more complex, and this might be the challenge of this particular investigation. Would soil pH effect the enzymes in the seed responsible for germination, is there another explanation? Controlling other factors which affect germination and collecting a large enough data set will also be good challenges for a Biology student to work out.
Investigation of the functioning of the eyes when using paper or different electronic screens
First is to ensure that there is some biology to explain any hypothesis, and that the RQ is firmly focused in the Biology. Then is is going to be a challenge to design a method of data collection which controls all the possible variables. Some independent variables will be easier to test than others, for example size of text and distance wt which it can be read, would be better than measuring reading speed which can be affected by many other variables.
Examining the effect of household cleaning products on the growth of house plants
This could be a difficult investigation to do quantitatively unless there was a longer time period available to observe growth. There could be some biology theory applied to the plants leaves, or roots. Processes such as diffusion and osmosis as well as the effect of chemicals on components of cell membranes, or on enzymes could be included in the theory. Some of the challenges of this type of investigation will be controlling other factors which affect the growth of plants. One option might be to test the chemicals on small aquatic plants, or germinating seedlings, but there are challenges to overcome here too.
Investigation of the effects of natural selection related to colour markings of a single species of animal or plant
This is a great idea, but it could be complex and time consuming depending on the lab. There are some online simulations but these can only be used in conjunction with some other analysis; never just present the online lab as an investigation on it's own. Other possibilities are paper simulations, e.g. with peppered moth types. Practical work could look at the density of aphids on leaves of different shades, or bumble bee feeding on flowers of different shapes or predator prey interactions etc. Lots of scope but not an easy investigation to complete in the time, in 12 pages.
Are the limits of manufacturer's instructions reliable? E;g. the IKEA Växer hydroponic growing system.
Testing the manufacturer's instructions for a growing system could make an interesting IA. Why does it advise specific types of LED lights? What is the ideal daily light duration? Does changing the chemicals dissolved in the water for the hydroponic system affect plant growth. The challenge of this investigation would be to find a biological reason for a changed variable to have the effect predicted. Obvious one might be light intensity affecting photosynthesis, temperature affecting transpiration or enzymes, or location, fertilizer, type of water used.
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