Task of the Week: The weight of DCU

This week our presented task is located in Ireland. At the campus of the Dublin City University (DCU) our MoMaTrE partner Christian Mercat created the task “The weight of DCU” and gave us an interview about this task and the value of using the MathCityMap app. What´s the topic of the task? On the campus […]

Task of the Week

This week our presented task is located in Ireland. At the campus of the Dublin City University (DCU) our MoMaTrE partner Christian Mercat created the task “The weight of DCU” and gave us an interview about this task and the value of using the MathCityMap app.

What´s the topic of the task?

On the campus you can find a huge DCU solid rock sign. I really wondered how much that could weight! So I investigated and figured out that one could estimate the surface of the letters and the depth of the sculpture.

How could you solve this problem?

You have to estimate the average width of the letters and their lengths. For example, C is a 2/3 portion of a circle of diameter 2 m and average with 30 cm. So is has a surface of 1.2 m². The modelling of D and U happens equally. Totally the sculpture has a surface of 4.5 m². The depth of the stone is 50 cm, which leads to a total volume of 2.25 m³. The density of the stone being 2.4 (that’s given in the first hint), the total weight of the sculpture is around 5400 kg. The estimation of the surface being tricky, I actually checked again by taking a picture from a distance and estimating numerically the total surface with the help of my computer. 

Estimation of the sculptures` surface.

What´s the didactic aim of the task?

Clearly, I want here to get first the students to have a rough estimation of the degree of magnitude, is it around hundreds of kg, a few tons or tens of tons. I give a broad « orange » zone between 3000 and 7500 kg for those trying to figure out by simply bracing their arms around the sculpture to get a sense of the volume, which I find fair enough for an answer. But then, trying to model each letter as simpler geometric shapes is really the main focus of this task. It can not be done exactly, the average width of each letter is a matter of debate, which is good. The « green » zone might be a little bit too tight (between 5000 and 6000) which is only a 20% width around the expert estimation, but the depth is without any doubt 1/2 meter so the uncertainty really is on the surface estimation.

Why do you use MathCityMap?

I love taking the pretext of a MathCityMap trail in order to stroll around on a campus or in a park, appreciating the scenery from this very specific perspective of looking around for objects that tickle my mathematical inclination, keeping open the scientific eye in me.

Task of the Week: The green ear

Today´s task of the week is located in Lüneburg, Germany, where the teacher trainee Jennifer Oppermann created the task “The green ear”. She gave us an interview about this task, mathematic modelling and the MathCityMap project. What´s the topic of the task? The question is, how tall the human being would be, the green ear […]

Today´s task of the week is located in Lüneburg, Germany, where the teacher trainee Jennifer Oppermann created the task “The green ear”. She gave us an interview about this task, mathematic modelling and the MathCityMap project.

What´s the topic of the task?

The question is, how tall the human being would be, the green ear belongs to. To solve the task students first have to measure the sculpture of the green ear, followed by measuring an ear of a student. In addition, the body size of this students should be identified.

Afterwards the quotient of the length of the green ear and the students´ ear is multiplicated with the body height of the student. Thereby the size of the human being, to whom the green ear would belong, can be estimated.

What´s the didactic aim of the task?

While working on the task, students should improve their competences in mathematic modelling. Modelling means to link the reality and the mathematic and to solve a given problem through a mathematic calculation. Thus, MathCityMap is a helpful tool to observe the connection between environment and mathematics and to exert mathematical strategies.

How do you use MathCityMap?

To discover our near environment out of a mathematical perspective, we created a math trail through the Hanseatic town of Lüneburg. The MathCityMap project enables mathematic interested people to solve our tasks around Lüneburg and to increase their mathematical competences.

Task of the week: Volume of the bottle

The task of the week is back! Today we present you a task, which was developed during a teacher training at the Georg-Büchner-Gymnasium in Bad Vilbel near Frankfurt. Next to the schoolyard we found this interesting sculpture of a water bottle. Immediately we wanted to ascertain, how many litres of water the bottle would contain. […]

The task of the week is back! Today we present you a task, which was developed during a teacher training at the Georg-Büchner-Gymnasium in Bad Vilbel near Frankfurt.

Next to the schoolyard we found this interesting sculpture of a water bottle. Immediately we wanted to ascertain, how many litres of water the bottle would contain. For the task “Volume of the bottle” we assume that the artwork has a wall thickness of 3 cm.

How the volume of the bottle can be ascertained?

For the modelling we divide the artwork in a frustum of a cone and a circular cylinder. We look on the object as compounded solid.

What´s the aim of the task?

The complexity of the task is to find a useful mathematic model for the object, which is a fitting transfer of the reality and is calculable with a manageable time exposure all at once. To solve the problem, you have to find a compromise between mathematical precision and practicability. Hence the task is a good example for a lot of modelling problems.

Task of the Week: The Hexagon

This time the task is located in Grahamstown, South Africa. Calculate the area of the hexagonshaped table. Give the result in units of m². The task can be solved in different ways. Once you can divide the area into six equilateral triangles. It is also possible to divide the area into a rectangle and two triangles.

This time the task is located in Grahamstown, South Africa.

Calculate the area of the hexagonshaped table. Give the result in units of m².

The task can be solved in different ways. Once you can divide the area into six equilateral triangles. It is also possible to divide the area into a rectangle and two triangles.

Task of the Week: The volume of Mendeleïev

This time the task is in Bratislava, Slovakia. Dmitri Ivanovitch Mendeleïev (Дмитрий Иванович Менделеев) set up the periodic table of the elements arranged as rays around the sculpture of his portrait. Calculate the volume of this sculpture in cubic meters. The sculpture has the shape of a hemisphere. Therefore, the volume can be calculated using […]

Task of the Week

This time the task is in Bratislava, Slovakia.

Dmitri Ivanovitch Mendeleïev (Дмитрий Иванович Менделеев) set up the periodic table of the elements arranged as rays around the sculpture of his portrait.

Calculate the volume of this sculpture in cubic meters.

The sculpture has the shape of a hemisphere. Therefore, the volume can be calculated using the diameter.

Task of the Week: The crocodile at the goldfish pond

Today, MCM talks with Jörg Kleinsteuber (MCM Educator) about the task of the week in Apolda, Germany. If the wooden crocodile would come to life and eat, the goldfish would have “bad cards”. Decide what amount of food would need a mature 6 meter specimen compared to a crocodile the size of the wooden crocodile. […]

Today, MCM talks with Jörg Kleinsteuber (MCM Educator) about the task of the week in Apolda, Germany.

If the wooden crocodile would come to life and eat, the goldfish would have “bad cards”. Decide what amount of food would need a mature 6 meter specimen compared to a crocodile the size of the wooden crocodile.

What is the task about?

The beautifully carved wooden model is a small version(centric extension) of a crocodile. Since the length of a full-grown crocodile is a multiple of the model, this unusual task can be created from it. Already in the book “Gulliver’s Travels” by Jonathan Swift, the 12x larger Gulliver got the clothing (surface) of 144 Lilliputians and his food portion would have been enough for 1728 by the Winzlings. This mathematical effect of the stretch factor on the area and the volume is always amazing. I chose Multiple Choice as the answer format because I did not want to measure exactly, but to understand and apply knowledge.

For what purpose was the task created?

The task was created for a workshop with teachers on the SINUS-Landtag https://www.schulportal-thueringen.de/sinus_thueringen in Apolda (in the Hotel Am Schloss https://www.hotel-apolda.de/).

When we went to the conference, I got a shock – the crocodile was gone … and thus the task is no longer solvable.

The conference manager spoke therefore with the hotel staff and the caretaker then took the crocodile from hibernation from the basement (great service, thank you!)

So the participants could still solve this unusual task; It was a tough nut, but it was fun.

Afterwards, I even thought about exchanging the photo so that the size of the crocodile can be used to determine its size, even if it sleeps in the cellar in winter.

What do you like about MathCityMap?

What fascinates me about MCM is the combination of classical mathematics with digital support. Mathematics does not have to mean complicated bills and expensive applications. Small tasks with practical relevance, in which the students themselves have to become ACTIVE by measuring, modeling, estimating, and discussing in small groups offer plenty of potential for student activities.

The possibility of using the smartphone as a support is self-evident for students and at the same time motivating. At the same time this reduces my effort in the care, because the APP provides feedback in the form of hints, model solutions and also offers gamification (points). A great mix!

The new “digital classroom” allows me to chat with students while they are completing tasks (answer questions) and I can see their walkways while they’re on the trail.

In the follow-up in the classroom we had very stimulating discussions about the tasks.

Thank you for the interview and your commitment to MCM!

Task of the Week: Mushroom at the Kaiserdomgymnasium

This time we present a task from Speyer, Germany. The object is a popular sculpture by the artist Wolf Spitzer. “Sigillum”, bronze 1994, seal stamp – planetary gear that turns on its own axis and touches the nearby museum wall. The Sigillum represents the preservation of history and culture. The shape of the figure is […]

This time we present a task from Speyer, Germany. The object is a popular sculpture by the artist Wolf Spitzer.

“Sigillum”, bronze 1994, seal stamp – planetary gear that turns on its own axis and touches the nearby museum wall. The Sigillum represents the preservation of history and culture.

The shape of the figure is often interpreted by the local people as a mushroom, hence the name of the task. Geometrically, these are two conntected cylinders.

Calculate the volume and give the result in liters! One liter equals 1 dm³.

For the big cylinder it is difficult to measure the circumference. In contrast, it is easy to raise the diameter. For the small cylinder it is not difficult to measure the circumference. It is therefore very likely that when working on the task, there are different ways to calculate the volume of the two part-bodies.

If one raises the measured values ​​in decimeters, the result is obtained directly as the sum of the two volumes.

Task of the Week: Ernst-Abbe monument

The task of the week is this time aboutthe Ernst-Abbe monument in Jena, Germany. How often does the volume of the sphere fit into the truncated pyramid? To solve the problem, the sphereand the truncated pyramid must be measured in order to calculate their volume. Then divide both sizes. The interesting thing about this task […]

The task of the week is this time aboutthe Ernst-Abbe monument in Jena, Germany.

How often does the volume of the sphere fit into the truncated pyramid?

To solve the problem, the sphereand the truncated pyramid must be measured in order to calculate their volume. Then divide both sizes. The interesting thing about this task is that the solution interval contains a special number .

Task of the Week: No Entry

This time the task of the week is on the site of the VW Autostadt in Wolfsburg. Everything is a little smaller on the traffic training ground than it really is. A “No entry” sign usually has a diameter of 42cm. How much bigger is a normal shield than the one used here? To solve […]

Task of the Week

This time the task of the week is on the site of the VW Autostadt in Wolfsburg.

Everything is a little smaller on the traffic training ground than it really is. A “No entry” sign usually has a diameter of 42cm. How much bigger is a normal shield than the one used here?

To solve the problem, one has to measure the diameter of the shield first. Later on the areas of both shields have to be calculated and put into proportion. The result is the scaling factor of the area.

Task of the Week: Circles in the cobblestone

The task is Apolda, Germany. Determine by what percentage the first circle with the dark stones is larger than the inner circle (light stones). To get the solution of the task, one can make different models. On the one hand it is possible to count the light and dark stones and calculate the ratio. Another […]

The task is Apolda, Germany.

Determine by what percentage the first circle with the dark stones is larger than the inner circle (light stones).

To get the solution of the task, one can make different models. On the one hand it is possible to count the light and dark stones and calculate the ratio. Another possibility is to calculate the area of a circle and a annulus.

It is not enough to calculate only the ratio of both stone types. To get the right result, the ratio must be converted to percent and then reduced by 100. Only then someone knows how many percent larger the annulus is than the inner circular area.

Thanks to MCM Educator Jörg Kleinsteuber for this task.