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The new tasks
of the Science Section
of the Educational Research Institute
Presented tasks are prepared by the Science Sec-tion of EducaSec-tional Research Institute for the third and fourth stage of education. Some of them were construct-ed for the study Laboratory of thinking and declassificonstruct-ed after the second stage. Presented tasks have not been previously published. They are valuable mostly because of the significant practical context: touching real prob-lems that students may encounter in everyday life.More about the Laboratory of thinking you can find on the web: http://eduentuzjasci.pl/en/en-badania- naukowe/120-english-categories/research/512-labo- ratory-of-thinking-diagnosis-of-science-education-in-poland.html
The items and commentaries are created in the franework of the project Quality and effectiveness of education – strengthening of institutional research capabilities implemented by Instytut Badań
Edukacyjnych (Educational Research Institute) co-financed by the European Union under the European Social Fund.
Biology – An incident with a mutagen
Task
A laboratory worker incidentally pour on himself a small amount of a strong mutagenic agent. The sub-stance was immediately removed from his skin and clothes in accordance with the safety procedures of the laboratory.
Decide, which of the consequences are possible. Consequence Is it possible?
1
The incident won’t have any impact on the worker’s health.
Possible / Impossible 2 The worker will get cancer
in effect of this incident. Possible / Impossible 3
The incident will make the worker develop haemo-philia
Possible / Impossible
Commentary
The situation described in the stimulus material is realistic and may happen in a laboratory. Student’s task is to predict possible consequences of the incident with a mutagenic agent and, therefore, to describe a potential influence that a mutagenic substance may have on hu-man health. It is noteworthy that this item also checks whether the students are capable of thinking in the terms of probability: not all possible consequences have to occur and a small probability does not mean that the consequence is impossible.
This task item was used in a study carried out among students who completed lower secondary education (IC-SED level 2). It was difficult: only 27% of the students correctly determined possibility of all three events. The
first consequence (no influence on the worker’s health) was the easiest to judge (72% of correct answers). This scenario is obviously possible for many reasons. First of all, the mutagen was immediately removed from the skin that itself is an impermeable barrier for many substanc-es. It is therefore probable that the harmful substance did not even enter the organism. Moreover, even if the mutagen penetrated the tissues, it does not mean that it would cause any mutation, because in human cells there are several enzymes that constantly repair any changes in DNA that the mutagenic agent may make. And even if some mutations did happen, they may have no effect on the whole organism or even on a single cell.
On the other hand, one cannot rule out the possibil-ity that the mutagen will affect one of the genes called proto-oncogenes. A mutated proto-oncogene may turn into oncogene that facilitates the transformation of a normal cell into a tumor cell. This means that the second consequence is also possible. Sadly, only 55% of students chose the correct answer. Those who chose the wrong answer may have not understood that mu-tations can lead to cancer. Alternatively, having chosen the answer that the incident probably will not have any negative effect on worker’s health, they consequently re-jected other possibilities. Indeed, in this case the prob-ability that the lab worker develops a cancer is very low but it is still possible, for instance if the skin has already been exposed to some other mutagens. Moreover, a can-cer may develop from a single mutated cell.
The third consequence may be excluded without any doubts. Although haemophilia is caused by a single point mutation, the probability that the mutagen deeply penetrates the body and affects exactly the same genes in many cells at the same time practically equals zero. The correct answer was chosen by 67% of students.
The presented task would be most useful as a part of a class test covering topics in genetics.
The authors:
BIOLOGY – author of the item: Paweł Jedynak; author of the commentary: Andrzej Papaj
CHEMISTRY – author of the item: Małgorzata Musialik; author of the commentary: Małgorzata Musialik
GEOGRAPHY – author of the items: Katarzyna Mijakowska; author of the commentary: Anna Markowska
PHYSICS – author of the item: Maciej Trzebiński, author of the commentary: Helena Howaniec
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Chemistry – Asian flavours – Nigari
Task
Nigari (japanese ‘bitter liquid, soup, brew, brine’) is
an Asian spice with a characteristic salty-bitter taste. It contains nearly 95% of magnesium chloride and a small amounts of magnesium sulfate and micronutrients. It is obtained from sea water as a byproduct of desalina-tion, after the crystallization of sodium chloride. Nigari is used as a dietary supplement to fill up magnesium de-ficiency in the body, and as a natural coagulant in the production of tofu.
Source: http://pl.wikipedia.org/wiki/Nigari
Analyze the text above, and then select the correct answer.
1) Nigari is obtained from seawater by A. filtration,
B. evaporation, C. decantation, 2) because
A. magnesium chloride is a water soluble salt. B. magnesium chloride is not a water soluble salt.
Commentary
The item concerns the method of obtaining spice with an exotic sounding name, which is basically a sim-ple, well-known to students from the classroom lab, chloride salt, thus its context forms part of the so-called
kitchen chemistry, that draws ideas from everyday life
experience. Although the knowledge necessary to solve this item is listed in the requirements for the 3rd stage of education (methods of separating mixtures, salts, solubility), this task can be successfully used also in the upper secondary schools, during realization of the
sec-tion 3. Chemistry supports our health. Chemistry in the
kitchen (the meaning and consequences of the usage of food additives).
A skill tested in this item is reasoning about the way to obtain a substance on the basis of text analysis. The student must deduce which method can be used to sep-arate magnesium chloride from the solution of seawater and what properties of this salt determine the way of obtaining it.
To solve the item correctly student should:
• know what are the processes of filtration, evapora-tion, decantation and crystallization;
• analyze the content of item’s introduction and no-tice that seawater has two basic mineral compo-nents: sodium chloride and magnesium chloride, wherein sodium chloride is separated from the seawater as first in the crystallization process, and thus the solution depleted of this component sho-uld be examined;
• if a student has an access to the solubility chart a matter is simple – he should check the chart, whether the salt composed of magnesium cations Mg2+ and chloride anions Cl is or is not soluble in water, and then conclude that, if the compound with a formula MgCl2 is soluble in water, then the correct answer in the 2nd part of the item is A;
• a student who does not have an access to the solu-bility chart may deduce that the magnesium chlo-ride is a water soluble salt based on the information provided in the item’s introduction and his own knowledge: firstly, anyone who has seen seawater knows that it is clear, homogenous solution, such as saline, secondly, sodium chloride (table salt) is a substance soluble in water and since it has been crystallized from the solution earlier, it means that it is less soluble than magnesium chloride; this
le-ads to the conclusion that the magnesium chloride is the salt which dissolves very well in water;
• select the separation method which allows to sepa-rate a mixture of water and magnesium chloride on the basis that a water-soluble substance cannot be separated from the aqueous solution otherwise than by water evaporation, and thus magnesium chloride can be obtained from an aqueous solution by evaporation of water only (answer B).
This item was tested on a group of 218 students from the 1st grade at upper secondary school. The results ob-tained by the students who were solving this task are reported below.
Table 1. The percentage distribution of students’ re-sponses to the questions posed in the item (the correct answers are marked with a star):
Answer Students’ responses [%]
1) Nigari is obtained from seawater by
1A. filtration, 6.0%
1B*. evaporation, 67.9% 1C. decantation, 26.2%
2) because
2A*. magnesium chloride is a water
soluble salt. 73.4%
2B. magnesium chloride is not
a wa-ter soluble salt. 26.6%
In general the entire item was properly solved by 54.6% of the students participating in the study, thus this task turned out to be rather difficult for students (the prob-ability of giving the correct answer at random equals to 16.6%). The item fairly well differentiated students in terms of skill level, i.e. the total score obtained by the student in the whole test. In the case of part 1, most stu-dents did not have a problem with indicating the cor-rect answer. The most frequently chosen distractor in this part of the task was decantation – more than 26% of the students marked exactly this answer. The number of students who found that magnesium chloride is not
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ter soluble salt was 26.6%, which is less than the sum of those choosing decantation or filtration as a method of separating mixture. These results suggest that perhaps some students did not know what filtration is and found that in this way you can separate each salt from aqueous solution, even a water-soluble one.
This item measures quite a wide range of knowledge and skills regarding the separation of mixtures, the solubility of salts and reasoning, moreover it diagnoses students’ skill level quite well, and therefore it is primar-ily intended for repetitive classes or tests. Because of the health benefits of nigari (a source of easily absorbable magnesium), the task can also be used in the classroom at upper secondary school during realization of learn-ing content in the section 3 of the core curriculum:
Chemistry supports our health, bearing in mind that the
knowledge gained at ISCED 2 level, is also valid for the 4th stage of education.
The item is compliant with the following require-ments of the core curriculum for chemistry:
ISCED 2 level:
Educational goals – general requirements:
I. The student acquires and processes information from multiple sources using Information and Communication Technologies (ICT).
II. Reasoning and application of acquired knowledge to solve problems.
2.1. The student describes the properties of substan-ces and explains the course of simple chemical processes; knows the relationship between the properties of various substances and their appli-cations, and their impact on the environment (...). III. Mastering the practical activities.
3.2. The student designs and carries out a simple che-mical experiments.
Contents – specific requirements:
1. Substances and their properties. Student:
8) describes the simple methods of separating mixtures and shows the differences between the physical properties of the mixture compo-nents that allow to separate them; prepares the mixture and separates them into components (eg. (...) water and salt (...)).
5. Water and aqueous solutions. Student:
1) examines the ability of various substances to dissolve in water;
2) (...) gives examples of substances that dissolve in water, producing homogenous solutions; provides examples of substances which do not dissolve in water, forming colloids and suspen-sions.
7. Salts. Student:
5) (...) on the basis of the solubility chart of salts and hydroxides concludes about the outcomes of precipitation reaction;
6) lists the use of major salts: (...) chlorides. ISCED 3 level:
Contents – specific requirements:
3. Chemistry supports our health. Chemistry in the kitchen. Student:
5) (…) shows the meaning and consequences of the usage of food additives.
Physics – Energy efficiency
Task
All home appliances must have an EU Energy La-bel with the information about their efficiency, which is rated in terms of energy efficiency classes from A to G, A being the most energy efficient, G the least efficient. Within class A grades A+, A++ and A+++ were later introduced. Comparing two similar appliances serving the same purpose, the more efficient is the one, which consumes less amount of energy.
Which of the following statements can be concluded from the information given above:
Statement Conclusion
1 The appliance of the energy efficiency class G is cheaper than the others. True / False
2
If we buy appliances of lower energy efficiency class we pay more for electri-cal energy.
True / False
3
It is better to buy a more expensive appliance of higher efficiency because we will gain money back paying less for energy.
True / False
4 The appliances of the class A+++ are most durable and do not break easily. True / False
Commentary
The task evaluates students’ ability to analyze and draw conclusions from popular science texts. It presents classification of the home appliances according to their energy efficiency.
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Some smart students could ask whether it is pos-sible that one device needs more energy than the other while doing exactly the same work. The conservation of energy rule confirms that the same amount of energy is needed to do the same work. Why one device needs more energy than the other? The problem lies in the amount of energy lost in the process of transferring one form of energy into another. For more efficient appli-ances the loss of energy is smaller.
The task was used in the educational research car-ried out in Polish lower secondary schools aiming at evaluating students’ ability and skills in solving scien-tific problems.
Students taking part in the research had to decide whether the statements deduced from the text are jus-tifiable.
Let’s analyse four presented statements:
1. The appliance of the energy efficiency class G is cheaper than the others.
There is no sufficient information in the text to sup-port such an opinion. We know, from everyday life, that it is not always true. 70% of students rightly denied that statement.
2. If we buy appliances of lower efficiency class we pay more for electrical energy.
According to the rules described in the text, the statement is correct because lower efficiency class appli-ances consume more energy for the same work. If we had more quantitative data (power, time of connection to the mains supply) we could calculate the exact value of the energy consumed. 70% of students appropriately chose the true answer.
3. It is better to buy a more expensive appliance of higher efficiency because we will gain money back paying less for energy.
The suggestion can be right but not necessarily. There is not enough data to prove it. It depends on dif-ference in the prices of two similar devices of different energy efficiency classes. Over 82% of students rightly indicated the false choice.
4. The appliances of the class A+++ are most durable and do not break easily.
Logically thinking it should be true, but unfortu-nately it is not always evident and we do not have suf-ficient information to conclude such a statement. A big majority of students (67%) deduced incorrectly that if the appliance is of the higher class it must be very reli-able. Only 33% had some, justifiable doubts about it.
All the task, the correct judgment of all four state-ments, was rightly verified by only 2% of all students taking part in the survey. The result is very pessimis-tic and shows that young people are very susceptible to all kinds of suggestion (TV commercials etc.). Particu-larly, suggestion 4 (efficiency and durability are tightly linked) was wrongly concluded by most of the students. People want to belief that high effectiveness and high quality are more or less the same. It is a pity that this seemingly obvious statement is not always true.
On the other hand, the survey results show some op-timistic aspects. For example, the suggestion concern-ing quick reimbursement of costs while buyconcern-ing more expensive appliances in statement 3 did not generally meet students enthusiasm. Rightly so. We can presume that young people (at least some of them) got tired of commercials based on such an argument.
The task can be used by science teachers in realiza-tion of the core curricula for:
Third stage of education, basic level: Educational goals – general requirements: IV. Handling information and problem solving while
analyzing texts (popular science text including)
Contents – specific requirements:
4.10. Electricity. A student demonstrates a quanti-tative understanding of electric current, its work and power.
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Geography
– The route between the camps
Task
The map shows the proposed routes which scout troops can choose in order to reach camp B from camp A.
Commander of the youngest troop wants to find the easiest route between camps A and B. The easiest route has the smallest differences in elevation.
Indicate the appropriate route. A. 1
B. 2 C. 3 D. 4
Commentary
Presented task can be used on the 3rd educational stage (gymnasium) and it checks skills of the map inter-pretation, especially reading information using contour lines.
Contour lines, also called isohypses, are lines drawn on a map connecting points of equal elevation. Contour lines show elevation and the shape of the terrain. They are useful because they illustrate the shape of the land surface – its topography – on the map.
By using contour map student can interpret differ-ent characteristics of the terrain, for example:
• indicate the height above sea level of a location (in the other words, determine the altitude),
• calculate differences in elevation between chosen points (in the other words, determine the relative height),
• termed landforms and their parts, which we can find on the map (form example: valley, culmina-tion, mountain pass, shallow slope or steep slope),
• calculate the length and the surface of chosen obje-cts, for example river or forest.
In proposed task student should indicate which of the four routes between camps A and B is the least tiring and should be chosen by commander of the youngest troop. The command for this task includes information that the easiest and the least tiring route is the one that
has the smallest differences in height. To successfully solve this task, the student should:
• find camps A and B on the map (find points A and B);
• analyze all route between camps A and B, taking into account the differences in elevation on each route. Students can read this information from contour lines – the more contour lines intersect the route, the greater differences in height has a route. Additionally, distant contours show
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low slopes while close contours indicate a steep slopes;
• choose the route, which has the smallest differen-ces in elevation.
More than half (53%) of students successfully solve this task and indicate answer D – route 4. It may be not-ed that the route number 4 is locatnot-ed mostly on the one contour line, so the differences of elevation are small and smaller than on the other routes (1, 2 or 3). Answer selected in the second place is A, the route 1 (19%). This could be due to the fact that the other route – 2 (13%) and 3 (12%) – are closer to the culminations, marked on the map. For this reason, the students can immediately reject response B and C.
Proposed task can be used during the lesson or as a question in a test. This tasks is worth discussing dur-ing the first lesson related to illustrate the shape of the land surface on contour map. Additionally, using con-tour map students may be taught about altitude, relative height or differences between shallow and steep slopes.
The item is compliant with the following require-ments of the core curriculum for geography on the third educational stage:
Educational goals – general requirements: I. Utilization of various sources of geographical
in-formation. A student can use plans, maps, pho-tographs, drawings, diagrams, statistical data, source texts and information-communication technologies in order to collect, process and pre-sent geographical information
Contents – specific requirements:
1.8. A map – skills of reading, interpretation and using the map. A student: analyses and interprets texts of general-geographical, thematic, tourist maps
The task „The route between the camps” can be also used in primary school during nature lesson to realized general and detailed requirements:
Educational goals – general requirements:
5.1. Observations, measurements and experiments. A pupil utilizes various sources of information (their own observations, examinations, experi-ments, texts, maps, tables, photos, films), carries out measurements and uses instructions (verbal, text, graphic)
Contents – specific requirements:
2.4. Orientation in the field. A pupil identifies the pla-ce of observation and the objects in the nearest surroundings on the plan and topographical map, determines location of the objects towards each other on a plan, a topographical map and in the field;
2.7. Orientation in the field. A pupil distinguishes convex and concave forms in the field and on the model, indicates these forms on a contour map. If we would like to use the task „The route between the camps” in primary school, the best way is to discuss it during the lesson.
