15 Spheres
What shape has the smallest surface for the same volume?
The cone
The cylinder
The sphere
The sphere is the body with the smallest surface/volume ratio. Therefore, many fruits and vegetables have a rather round shape: the production of the peel requires a higher energy, so it is advantageous to produce as little of it as possible. Since the sphere has the largest volume in regards to the smallest surface, it is the optimal shape.
The sphere is the body with the smallest surface/volume ratio. Therefore, many fruits and vegetables have a rather round shape: the production of the peel requires a higher energy, so it is advantageous to produce as little of it as possible. Since the sphere has the largest volume in regards to the smallest surface, it is the optimal shape.
If you have an ice cube and an ice sphere of equal volume, which one melts faster?
The ice cube
The ice sphere
Both melt the same way
As we found out in the previous question, the sphere has the smallest possible surface. As a result, the contact surface with the warm outside world is smaller and the sphere melts more slowly.
As we found out in the previous question, the sphere has the smallest possible surface. As a result, the contact surface with the warm outside world is smaller and the sphere melts more slowly.
What shape does a 2 mm large falling rain drop have?
a
b
c
When a drop begins to detach from a body, a constriction occurs. However, this does not taper any further to the known drop shape, but stretches in length until the drop detaches from the thread.
When a drop begins to detach from a body, a constriction occurs. However, this does not taper any further to the known drop shape, but stretches in length until the drop detaches from the thread.
Why is a falling drop spherical?
Because of the surface tension
Because of the Doppler-effect
Because of the Matilda-effect
The water molecules attract each other. This means that a molecule inside the drop is surrounded by other molecules that interact with it. The water molecules located on the surface of the drop are surrounded by the air outside the drop with which they interact only very little. However, the water molecules inside the drop still attract the outer ones, creating a force directed towards the center of the drop, the so-called surface tension. This causes the drop to occupy the smallest possible surface, a sphere.
The water molecules attract each other. This means that a molecule inside the drop is surrounded by other molecules that interact with it. The water molecules located on the surface of the drop are surrounded by the air outside the drop with which they interact only very little. However, the water molecules inside the drop still attract the outer ones, creating a force directed towards the center of the drop, the so-called surface tension. This causes the drop to occupy the smallest possible surface, a sphere.
What is the roundest object on earth?
A drop of water
The Earth itself
A human-made silicon sphere
It was made by an international team of researchers, has a diameter of 10 cm and has a roughness of approximately one nanometer. If the sphere were as large as the earth, the highest mountain would be only 2 m high. This silicon sphere was created to possibly replace the standard kilo; a 39-millimeter platinum iridium cylinder locked away in a vault in Paris and continuously losing weight, which is a big problem. Now the kilo is to be bound to the number of atoms of this silicon sphere.
It was made by an international team of researchers, has a diameter of 10 cm and has a roughness of approximately one nanometer. If the sphere were as large as the earth, the highest mountain would be only 2 m high. This silicon sphere was created to possibly replace the standard kilo; a 39-millimeter platinum iridium cylinder locked away in a vault in Paris and continuously losing weight, which is a big problem. Now the kilo is to be bound to the number of atoms of this silicon sphere.
In molecular gastronomy, hot juice drops mixed with agar-agar are pipetted into oil to jellify them in spherical forms. Where does agar-agar come from?
From the cell walls of red algae
From fish eyes
From the roots of rapeseed
Agar-Agar is a polysaccarid, a multiple sugar in which the simple sugar agaros and agaropectin are connected. The cell wall in which the agar agar is located gives the cell a stable shape.
Agar-Agar is a polysaccarid, a multiple sugar in which the simple sugar agaros and agaropectin are connected. The cell wall in which the agar agar is located gives the cell a stable shape.
Spherification can also be used to create spheres in the kitchen. For this purpose, sodium alginate is added to the desired liquid and dripped into a water bath. Which salt contains this bath?
calcium chloride
lithium chloride
cesium chloride
Calcium chloride: Sodium alginate consists of a negatively charged alginate molecule and a simply positively charged sodium ion. Since the sodium ion is simply charged, it can only interact with an alginate molecule. If it is dripped into calcium chloride, the simply charged sodium is replaced by the twice charged calcium ion. This can then interact with two alginate molecules, forming a solid membrane.
Calcium chloride: Sodium alginate consists of a negatively charged alginate molecule and a simply positively charged sodium ion. Since the sodium ion is simply charged, it can only interact with an alginate molecule. If it is dripped into calcium chloride, the simply charged sodium is replaced by the twice charged calcium ion. This can then interact with two alginate molecules, forming a solid membrane.
Who is a well-known chef of spherical molecular gastronomy?
Johann Lafer
Lea Linster
Ferran Adrià
Ferran Adrià began his career as a simple dishwasher and quickly became a superstar among the chefs. Already in 1994 he experimented with molecular gastronomy. What initially attracted only a few audiences quickly became a 3-star restaurant. This restaurant is very selective : it only serves 8000 meals over half a year. Adrià generally spends spent the rest of the year researching new recipes.
Ferran Adrià began his career as a simple dishwasher and quickly became a superstar among the chefs. Already in 1994 he experimented with molecular gastronomy. What initially attracted only a few audiences quickly became a 3-star restaurant. This restaurant is very selective : it only serves 8000 meals over half a year. Adrià generally spends spent the rest of the year researching new recipes.
This quiz was written by the Luxembourg Science Center in Differdange. Visit the Centre to learn more about spheres and other scientific topics!
This quiz was written by the Luxembourg Science Center in Differdange. Visit the Centre to learn more about spheres and other scientific topics!
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Images copyrights:
1 Luxembourg Science Center
2 Luxembourg Science Center
3 Luxembourg Science Center
4 Luxembourg Science Center
5 Luxembourg Science Center
6 Luxembourg Science Center
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9/10/11 commons.wikimedia.org
12 commons.wikimedia.org
13 Luxembourg Science Center
14 commons.wikimedia.org
15 Luxembourg Science Center
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20 commons.wikimedia.org
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