Title: Grilli che c(a)ontano!
Class: first two years of Upper Secondary
Subjects: math, science, biology, physics, english
Teachers: Sabrina Nappi, Rosanna Busiello, Mario Di Fonza, Josephine Iannone
“Grilli che c (a) ontano” is a multidisciplinary activity that involves the STEM disciplines: mathematics, physics, science and biology, and its focus is the study of climatic factors and the causes which are leading to an increase in temperatures, with the significant correlation of the temperature variation of the globe.
The activity begins with listening to cricket song:
https://www.youtube.com/watch?v=UGOS4e99kj4
students are asked to answer the following stimulating questions:
- why do crickets chirp?
- Did you know that only male crickets chirp?
Pupils respond on www.mentimeter.com and discuss
Possible answers: Crickets sing to….
- Call the female: male cricket’s challenge is to be loud enough to be heard
- courting ritual
- Drive other males away.
The song of crickets is the nocturnal soundtrack of our collective rural, suburban and even urban lives.
Some other questions:
- can a cricket help to study climate change?
- If so, how?
A debate on the topic follows.
Subsequently, the insect was introduced as a species belonging to the orthoptera family, and as an insect that emits sounds called chirps
Listening with greater attention to the song of a cricket https://www.youtube.com/watch?v=UGOS4e99kj4
the most bizarre and interesting thing to observe is that this song is discontinuous and is related to the temperature
When the weather gets warmer you can hear the crickets “sing”, which they do by rubbing their legs. The warmer the weather is, the faster they “sing”.
The goal is therefore to predict the temperature on the basis of the perceived chirps. Not everyone knows that crickets are considered the thermometers of the poor, an expression that comes from the observation that the chirping of these animals increases or decreases in relation to the temperature of the environment. Like all other insects, crickets are cold-blooded, which means they take on the temperature of their surroundings. As the temperature rises, it becomes easier for them to chirp, while when the temperature drops, the reaction rate slows down, causing a cricket’s chirping to decrease as well.
Engagement is curious and invites students to verify this discovery.
Through the study and analysis of data relating to the variables involved, such as location temperature and the chirping of crickets, students investigate and explain the study phenomenon.
Investigation phase
Students are provided with data taken from a research carried out in 2007 in Boulder (Colorado, USA), and are asked if it is possible to find a relationship between the number of crickets’ chirps (f) and the location temperature (t) .
The methodology is workshop type: students analyze the data and build a scatter chart by observing how the points are arranged through the use of google sheets, and discuss it in groups. The relationship sought is of the type: t = a ∙ f + b and establishes the value of the correlation between the data examined. The mathematical model is the equation of the line passing through the points in order to have a quantitative approximation of the regression and calculate the correlation coefficient.
The mathematical concepts concern the relationship between two quantitative variables and the analysis of simple regression and correlation as tools for evaluating the relationship between an independent variable and a dependent one.
In relation to the new perspectives, students deepen the concept of a simple and predictive mathematical model.
Reading the blog
https://www.globe.gov/explore-science/scientists-blog/archived-posts/sciblog/index.html_p=45.html
As an in-depth analysis, students are asked to surf the net for data relating to the population of crickets located in the area, and to create problems with the elementary tools such as proportions, percentages, graphical and tabular representation of data, forecast models, etc.
From the analysis of the data, students move on to analyze Dolbear’s Law in physics
Amos Dolbear, was a 19th century American physicist, professor and inventor who studied various species of crickets to determine the relation between the number of chirps per minute and the ambient temperature
In 1897, he published an article “The Cricket as a Thermometer”, in which he developed the following simple formula (now known as Dolbear’s Law): T = 50 + ((N – 40) / 4)
where T is the temperature in Fahrenheit degrees and N is the number of chirps per minute.
Students are asked to go from Fahrenheit degrees to Kelvin degrees and then to Celsius degrees
Note: Dolbear’s Law is best for estimating temperature when using tree cricket chirps, when the temperature is between 55 and 100 degrees Fahrenheit, and on summer evenings when crickets feel best.
Deepening with the sciences
Students reflect on the question: What happens in human beings if the internal temperature increases? Hence the connection between physics and science: the heart beats faster if the internal temperature rises.
Pupils are asked, in pairs, to determine and share their body temperature by measuring the frequency of heart beats per minute, taking into account the relationship between heart activity and the internal body temperature reported:
- Resting adult with 70 beats per minute = 37 ° C of fever inside the abdomen.
- Resting adult with 80 beats per minute = 37/38 ° C of fever inside the abdomen
- Resting adult with 90 beats per minute = 38 ° C of fever inside the abdomen
- Resting adult with 100 beats per minute = 39 ° C fever inside the abdomen
- Resting adult with 110 beats per minute = 38/39 ° C inside the abdomen
- Resting adult with 120 beats per minute = 40 ° C inside the abdomen
pupils discussed on the table, observing how each degree Celsius of body temperature increase corresponds on average to 8 beats per minute increase in heart rate
Obviously, temperatures that go above 37 ° are typical of a person with fever, so to have different results, pupils tried to “warm up” by running or doing some physical exercise.
To learn more, refer to
https://www.fondazioneluvi.org/wp-content/uploads/2018/11/parametri-vitali-23-gennaio.pdf
The activity ends with the experimental part in biology which concerns the use of crickets to study the effect of temperature on the metabolism of cold-blooded organisms.
Small insects have a trachea where diffusion occurs, carrying oxygen and removing the carbon dioxide necessary for cellular respiration
Starting from the following chemical reaction
Students are asked to:
– find the correlation between the two images.
– specify the reactants of this reaction, and the products;
– describe what they observe
– specify what are the factors that can slow down or speed up a chemical reaction, and explain why?
On a padlet (https://padlet.com/dashboard) the pupils enter their thoughts
The purpose of the activity is to determine how the temperature affects the respiratory rate of crickets by monitoring the production of carbon dioxide with a CO2 gas sensor at different temperatures. The amount of CO2 produced will determine the effect of temperature on the metabolism of crickets.
Students are divided into groups and they are provided by the outline of the procedure in order to monitor the data collection of cold, intermediate and hot temperatures which will be included in tables and subsequently analyzed as last step students will create related math graphs to be read.
The routline of the procedure
The CO2 sensor must be connected to the data collection device
If your CO2 gas sensor has a switch, set it to “Low” (0–10,000 ppm) placement. Change the data collection rate to 0.1 samples / second and the data collection duration to 600 seconds. Weigh 10 adult crickets in a 600 mL beaker and record their mass in Data and Observations.
Collect data at three different temperatures based on your assigned group number (I, II or III). Organize a water bath at a different temperature before each data collection. The class is divided into three groups, each one having a specific task
GROUP I: COLD TEMPERATURES
The group will collect data on respiration at 5–10 ° C, 10–15 ° C and 15–20 ° C.
Prepare a water bath for the desired temperature. This ensures that the crickets will remain at a constant and controlled temperature. How to prepare the water bath, get fresh water and ice. Combine the cold water and ice in 1 liter beaker until you reach the desired temperature range. The beaker should be filled with approximately 600–700ml of water. Leave the thermometer in a water bath during the experiment. Place the breathing chamber in the water bath and remove enough water to prevent spillage later during data collection. Be sure to keep the water bath temperature constant while collecting data. Use a pipette to remove or add hot or cold water as needed. Record the water bath temperature in the Data and Observations file
GROUP II: Intermediate TEMPERATURES
The group will collect respiration data at 20–25 ° C, 25–30 ° C and 30–35 ° C and will proceed in the same way as Group I by recording the results in Data and Observations
GROUP III: Warm temperature
The group will collect respiration data at 35–40 ° C, 40–45 ° C and 45–50 ° C by recording the results in Data and Observations.
Conclusions
In this activity, thanks to the use of the IBSE methodology, the pupils observed how mathematical relationships are concretely found in nature, or how life, as we know it, depends on physical and biological factors. The purpose of this activity is to provide evidence on how the effects of global warming can cause negative impacts on ecosystems and on the metabolic activities of individuals. The energy emitted by the sun is captured by the planet earth and used by individuals to produce energy and work (metabolism), this energy must always be in balance with all other living beings so that a greater or lesser accumulation can cause alteration of biological systems and therefore of living beings.
Pupils reflect on the issues of climate change and how changes in environmental conditions can cause great effects since life can exist only in a limited and fixed range of conditions.
To learn more refer to:
https://difima.i-learn.unito.it/
https://it.wikipedia.org/wiki/Amos_Dolbear
https://www.fondazioneluvi.org/wp-content/uploads/2018/11/parametri-vitali-23-gennaio.pdf
https://www.greenme.it/vivere/salute-e-benessere/come-e-perche-misurare-febbre-polso-battiti/
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