... explore

• Für den Labor-Mixer brauchst du das Kurbel-Kraftwerk und die Energiewandel-Station.
• Entferne zwei Magnete und Klebebandstücke von der Energiewandel-Station.

Material

1) Rasterblatt explore-it
2) Doppelklebeband
3) Silikonschauch
4) 1 grünes Zahnrad
5) 2 Magnete
6) Hartschaumstab

Besorge dir ein schlankes, eher hohes Glas. Das Glas soll einen Schraubdeckel haben(Marmeladeglas, Konservenglas).
Das abgebildete Konservenglas ist ca. 11 cm hoch und hat einen Durchmesser von ca. 7 cm.

Sorge dafür, dass nichts auf deinem Arbeitstisch durch Wasser beschädigt werden kann. Halte ein Trocknungstuch bereit. 

• Schneide ein 5 mm breites Stück Doppelkleband ab.

• Klebe das Doppelklebeband in die Mitte des grünen Zahnrades auf dem Hartschaumblock.
• Klebe einen Magneten in die Mitte des Klebebandes. 

• Schneide 4 Hartschaumstücke von 3 cm Länge zu.
• Nutze dazu die Schneidehilfe, die du beim Bau der Energiewandel-Station gebaut hast.
• Bewege das Messer mit wenig Druck hin- und her und schneide den Stab etwa einen Drittel ein. 
• Drehe den Stab um 90 Grad und schneide ihn erneut etwa einen Drittel ein.
• Wiederhole diesen Vorgang.
• Beim vierten Schnitt schneidest du den Stab ganz durch (Film).

• Schneide zwei Stücke Doppelkelbeband von 1 cm Breite ab.
• Halbiere sie, so, dass du vier gleich grosse Stücke erhältst.

• Klebe die Doppelklebbandstücke auf die quadratischen Seiten der Hartschaumstücke.

• Klebe die 4 Hartschaumstücke auf die Grundplatte.
• Die Ecken der Hartschaumstücke berühren jeweils die Kanten der Grundplatte in der Mitte.

• In der Ansicht von oben kannst du gut erkennen, wo die Hartschaumstücke auf die Grundplatte geklebt werden.

• Schneide ein Stück Silikonschlauch von 2 cm ab. 
• Stecke den Stecker des schwarzen und des blauen Kabels in das Silikonstück (Pfeil). 
• Überprüfe, ob die Stecker an den roten Kabeln durch den Magneten miteinander verbunden sind.
• Nun ist dein Labor-Mixer betriebsbereit.

Wasser-Wirbel im Glas

• Fülle das Glas mit Wasser 
• Lege einen Magneten in das Glas und verschliesse es. 
• Stelle das Glas auf die 4 Hartschaumstücke.

• Drehe das Antriebsrad deines Kurbel-Kraftwerks. 
• Mache dies anduernd, bis du einen Wirbel im Wasser beobachten kannst. 
• Drehe weite und versuche den Wirbel bis auf den Boden des Glases zu bringen.
  Es entsteht ein faszinierendes Gebilde mit spiralförmigen Verdrehungen.

• Kannst du den Wirbel auch nur bis in die Mitte des Glases bewegen?

• Gelingt es dir, dass sich einzelne Luftblasen losreissen und nach unten gezogen werden?

• Was geschieht, wenn du die Drehrichtung änderst?
  
  
• Mache verschiedenartige Erpobungen, bis du die Wirkung des rotierenden Magneten im Wasser gut verstehst. 

Three phenomena, "friction", "contact-pressure" and "transmission" are important for the successful functioning of the handcrank power station.

... explore: Friction

You know for sure how important is a good shoe profile in winter. The recesses in the sole provide more friction between the shoe and the ground.
Friction plays an important role in your handcrank power station too.

• Remove the silicone hose from the generator axle.
• Try to produce electricity using the power station.

... explore: contact-pressure pressure

In order to steer on the mountain bike trail, you need to press the wheels of your bike into the trail. That is the only way the wheels will stay on the ground and you can make curves. During jumps the bicycle flies straight.
Within the handcrank power-station the generator axle is pressed against the actuator wheel using a rubber band. This is how you can get enough friction so that the handcrank power-station works well.

• Remove the rubber band & decrease as such the contact-pressure.
• Does your LED light up as reliably as before?
  

... explore: Gears & Transmission

So that your generator produces electricity the rotational speed must be sufficient.
You've probably noticed that the power station transmission is similar to a bicycle.

You could actuate the generator using a piece of hard foam. To produce light over a longer period, however, you would need to constantly replace the piece of hard foam again and again, one length at a time..

The wheel is an ingenious invention: a wheel provides an infinitely long distance!

With each rotation of the drive wheel, the length of the wheel circumference is transmitted from the generator axis.
The next revolution starts it all over again.

The inventor of this bicycle probably had this concept in mind and implemented it in reverse :-)

Add a mark to the silicone tube. This can be, for example, a mark with a pen.

• Discover the gear ratio between the drive and generator axis.
• You have to count how many rotations the axis of the generator makes during one rotation of the drive wheel.  
  

Possible findings:
One student counted 24 revolutions of the generator axis during one revolution of the drive wheel. Her handcrank power-station has a ratio of 1 to 24. What are your conclusions?

The drive wheel and the generator axis together form a transmission. The low speed of the drive wheel is translated into a large speed of the generator axis.

 
An additional task for ambitious mathematicians

For cars with an engine you will find a "rpm" - display. "Rpm" is an abbreviation standing for revolutions per minute, what "rpm" means.  

You've probably noticed that the LED lights up only above a certain rpm.  

• Calculate how many revolutions per minute (rpm) of the axle of the generator are necessary to light up the white LED.
  
• How many rpm does the red light to light up?

Frage:
Wie muss man sich verhalten, wenn man von einem Strudel in die Tiefe gezogen wird?

..erforsche: Auftrieb im Wasser

Vielleicht hast du schon bemerkt, dass du im Meer beim Schwimmen weniger Kraft aufwenden musst, um an der Wasseroberfläche zu bleiben. Noch mehr Auftrieb haben Schwimmer im Roten Meer. Dort ist Zeitung-Lesen ganz ohne Bewegungs möglich.

Frage:
Warum kann man im Toten Meer ohne zu schwimmen auf das Wasser liegen?

Frage:
Wo bleibt das Salz, wenn du es ins Wasser gibst und einen Moment wartest?

 
... explore: electricity generation with a handcrank powerplant

What do you already know: Every electric motor converts electrical energy into movement (= mechanical energy). For this purpose, the electric motor needs electricity. The electrical current moves the axis of the generator.

Is this true also in inverse?   Can a motor produce electricity? If you vigorously turn the axle of the electric motor, your motor makes power and the LED briefly shines. At that moment, your electric motor is a generator generating electricity!  
A generator is the inverse of an electric motor: In the generator, the axle gets moved, and the generator converts the kinetic energy (= mechanical energy) into electricity: an electric motor can therefore also be used as a generator.
It is exactly this realization that you will be implementing for the construction of your handcrank power station!

Build your handcrank power station
Proceed as follows for construction:  

1. Equipment rack and generator fixation
   (Black and purple parts)
2. Actuator wheel
   (Cardboard discs with crank handle)
3. Installing the actuator wheel onto the equipment frame
4. Compression device   (Rubber band)
5. Functional test

materials
1) 3 pins
2) 1 pushpin  
3) 1 rubber band
4) Generator with LED
5) 3 red gears
6) 1 green gear
7) Silicone tubing
8) 2 cardboard disks

material
1) 1 piece of graph paper
2) 1 piece of double-sided tape
3) 1 corrugated plate
4) 1 foam block
5) 1 wooden dowel of 3mm diameter (barbecue skewer)

Equipment rack and generator fixation

• Cut the corrugated plate through the eighth hollow chamber counted from the edge. This results in a corrugated sheet with seven hollow chambers.
• Keep repeating this. Now you have two cellular sheets with seven chambers.  

• Measure and mark the double-sided tape a piece of 0.5 cm length and cut it off.  
• Make two more such strips of 0.5 cm length and one strip of 2.5 cm length.  

Note:   Follow exactly the instructions for cutting the double-sided tape. This will ensure that you do not run out of double-sided tape before completion.  

• Glue the 0.5 cm wide double-sided tape in the middle of one of the two corrugated sheets.

• Bond the second corrugated plate flush with the first one.  
• This is the base for the generator.

• Glue the 2.5 cm wide double-sided tape in the middle of the two corrugated sheets.
• Remove the protective film.

• Place the generator in the middle of the two wall sheets, so that the cables protrude out the side.
• Press the generator onto the double-sided tape. It is ok if the cellular sheets get somewhat compressed.

• Prepare a piece of normal adhesive tape about 5cm long.
• Glue it on top of the generator housing
  Note: The tape must not touch the generator axis.
• Pull the tape around the underside of the generator & stick it on the bottom of the corrugated plate while under tension.
• Do the same on the opposite side.

• Cut a piece of corrugated plate 12.5 cm long.
• This is the base plate.

• Glue a 0.5 cm wide piece of double-sided tape in the middle of the bottom of the base.
• Remove the protective film.

• Bond the base with the generator flush with one end of the base plate.
• Note: If you are right handed, the cables protrude out the right (as in the picture), if you are left-handed, out the left.

• Prepare another piece of normal adhesive tape about 5 cm long.
• Stick it next to the generator on the base.
• Pull the tape over the sides of the base & adhere it in place under tension to the underside of the base plate.
• Do the same on the opposite side.

• Prepare another piece of normal adhesive tape about 5 cm long.
• Stick it on the generator housing
  Note: The tape must not touch the generator axis.
• Pull the tape around the side of the generator down and stick it in place under tension to the underside of the base plate.

• Stick 2 pieces of 0.5 cm wide double sided tape on the rectangular foam block.
• Remove the protective films.

• Bond the hard foam block flush onto the base plate.

• Fix the hard foam block to the base plate with normal tape.
• Attach tape around the hard foam block & the base plate at both ends.

Antriebsrad

• Cut a dowel to 6 cm length (with sharpened tip) and another one to 3.5cm.  

You will create a construction device to stick the discs together exactly one on top of the other With three needles are you doing you an auxiliary device, so you can stick the discs exactly to one another.  

• Place one cardboard disc on the rectangular foam block. One corner of the foam block is barely completely hidden by the disc.
• Push three pins about halfway into the foam block.
• Note: The needles have to be inserted vertically and each must touch the cardboard disc.

• Stick four pieces of 5mm wide double sided tape on the cardboard disc. Place them between the two circles.
• Stick one 2.5cm wide piece of tape in the center of the disc.

• Take the second disc & hold it just above the first.   The second disc must touch three pins.
• Lower the second disk onto the first and press it firmly.

• Remove the push pins.
• Put the actuator wheel into the center of the foam board.
• Impale the center of the actuator wheel using a push pin.

• Push the 6 cm-long dowel through the actuator wheel.  

•   Flip over the actuator wheel and cut away the pressed-out material using a knife.
• Press the blade flat on the actuator wheel and saw away the excess material by cutting against the wooden dowel.  
  Note Cut away only the extra cardboard! The dowel should not be cut.  

• Stick 8 short pieces of normal tape across the cardboard disc. This reinforces the actuator wheel, because the plastic of the tape is very tough.

• Impale again the actuator wheel using the pin then the dowel  

Install the actuator wheel on the equipment rack

• Place the actuator wheel centered on the hard foam board. The actuator wheel must slighty touch the generator axis.
• Use the sharpened dowel to pierce a marker in the hard foam board.

• Stick 8 short pieces of normal tape across the hard foam block. This reinforces the hard foam block, because the plastic of the tape is very tough.

• Center the disc on the rigid foam. The actuator wheel must slightly touch the generator axis.
• Use a pushpin in the hole of the actuator wheel to fully pierce tape layers.  

• Place the 6 cm dowel on the table with the tip pointing up.  
• Put the gear on the dowel (with the small gear below).
• Push the gear down to the middle (reason: the gear cuts grooves in the dowel).  
• Pull the red gear back to the extent that it only still holds the dowel.

• Push the dowel with the red gear through the hole of the actuator wheel.
• Make sure that the red gear is lying flat on the cardboard disc.  
• Use the green gear to push the dowel all the way through the foam.

• Flip everything over.  
• Hold the whole device such that your thumbs are holding the corrugated plate.
• Touch the dowel to the table.
• Press with your thumbs the corrugated sheet downwards until the sharpened tip of the dowel pierces through the corrugated sheet and it can not be pushed any deeper.

• Place a red gear on the dowel and press it against the black corrugated sheet.
• Cut off the sharpened tip of the dowel above the red gear.
• This works best if you vigorously engrave around the dowel with scissors and by then breaking the dowel.

• Stick a 2.5 cm wide piece of double-sided tape on another the red gear.

• Stick this gear on the actuator wheel.
• The gear should be about 2 mm from the edge of the actuator wheel.
• Insert the 3.5 cm long wooden rod into this gear.

 
Compression device

• Impale both sides of the foam base with long pins.
• These long pins will be separated from the edge by about 3 cm.  
• Stretch the rubber band around the generator from pin to pin.

Functional test functional test

• Turn the handcrank.  
• Thanks to the actuator wheel, you can now continuously produce electricity.  
• If the light does not turn on, even if you turn the generator in both directions, it is possible that small strands from one wire mistakenly touch the other wire, causing a "short circuit". Make sure that the wires are firmly attached to the LED base.   

• If the LED flickers while the handcrank is being turned, the generator axis is pressed too weakly against the actuator wheel.
• If this is the case, move one of the long pins in the compression device a few mm further from the generator, to increase the tension.
• The lit LED shows you now that, using the handcrank powerplant, you can produce electricity with your own muscle power.