"I have no special talent. I am only passionately curious" - Albert Einstein

Category: Grade 9

G9 Engineering Project_Create & Improve

Create and Improve

Steps to make this product (also posted on Develop and Plan)

  1. Model the parts that need to be 3D printed. Send it to the 3D printing request site.
  2. Assemble the 3D printed parts.
  3. Stick horses on the roof and immobilize motor to pillar using a glue gun.
  4. Make lemon battery with copper strips, zinc strips, wires, and lemon.
  5. Connect lemon battery and motor.

1.  Model the parts that need to be 3D printed. Send it to the 3D printing request site.

Diagram of overall parts

Parts that need to be 3D modeled & printed:

roof, horses, base, pillar, and frame


1) Roof

Measurements: 12 x 12 x 2.5 (cm^3) [(length) x (width) x (height)]

The shape of roof is simply dodecagonal pyramid with a hole on the bottom-middle. The hole is for the pillar to be assembled.

2) Pillar

Measurements: 2.7 x 2.7 x 11.5 (cm^3)

The length and width of the pillar are accurately calculated in order to exactly fit the hole on the roof. Inside the pillar is hollow as my plan to immobilize motor together with pillar is to fill glue stick inside the pillar, heat up the shaft of the motor, and stick it to pillar.

3) Base

Measurements: 12 x 12 x 5 (cm^3)

Unlike the roof, base is designed with hexagonal shape, as dodecagonal column does not give space to make a hole to pull out the wires connected to motor. Every hole in this piece is precisely measured for motor. The cylinder hole is to grab motor and two square holes are for pulling out wires from the base. The rectangular hole on the cylinder is designed in order to connect wire to the bottom of motor where the parts that need connection are.

4) Horses

Measurements: Cannot be defined (Approximately, 5.5 x 0.8 x 8.5 (cm^3), including the height of long pole on its back)

Four pieces with same model were printed. They are the most complex pieces in this product. Due to its complexity and small size, few legs were broken while removing supports.

5) Frame

Measurements: 7.5 x 19.8 x 7.5 (cm^3)

Two hemisphere holes are designed to put lemon on it. They will hold the lemon juice being spilled on the floor. The parallel holes on the hemispheres are to put copper and aluminum strips. Thereby, the lemon battery device can be organized neatly.


2.  Assemble the 3D printed parts

Assemble plan 1) Roof + Pillar

When assembling the parts, accurate measurement was the most critical condition to success. I gave 1mm difference of thickness between the hole and the pillar. Fortunately, it fit so rightly that I did not need to advise design or put additional work.

Assemble plan 2) Base + Motor

This image clearly shows the usage of holes on the base. Also for this one, measurements should be precisely calculated for the hole that motor comes in. It worked well too.

Assemble plan 3) Assemble 1 + Assemble 2 + Horses

The horses are stuck with glue gun. However, since a glue gun also melted the roof, it led the bottom of the roof to be bumpy. The final step of carousel part was the most struggling section in manufacturing works. The reason is because the shaft of the motor should be placed on the center of the pillar exactly vertically. After I made first try, I acknowledged that without the condition, pillar will spin in an odd angle with gigantic vibration caused by unbalanced movements. At the end, I filled the pillar with glue stick, heated the shaft of motor, and used the heat to melt the glue stick. After glue stick cooled down, the shaft of the motor was fixed. It somehow worked, but it was not satisfying enough. Some minor rattling sound and movement were still observed.


3. Stick horses on the roof and immobilize motor to pillar using a glue gun.

Pillar + Roof + Horses

Bumpy bottom of the roof is shown on the image above. The image also shows two holes have identical size which allows them to be fit perfectly.

Pillar + Motor + Base

The actual process of using the holes on the base. All of them were designed carefully and thoughtfully in order to avoid re-printing pieces which takes considerably more time and resources.

4. Make lemon battery with copper strips, zinc strips, wires, and lemon.

Copper and aluminum should be connected, other two wires are connected to motor. That is how to create electric current flow by transforming potential energy from lemon pieces to electric energy. Detailed information about how lemon battery works in Define and Inquire.


5. Connect lemon battery and motor.

This is the end of making process. As I did not plan to make a switch, the device should operate when the wires are all connected. Whereas the photo above shows that the product is not working appropriately though every components are placed alright.



The device did not work. As the carousel worked well when powered by AA battery, the reasonable problem is on copper and aluminum strips or deficient power supply of lemon battery.


To be continued in Reflect and Share about why the device did not work.

G9 Engineering Project_Develop & Plan

Develop and Plan

Applying and reflecting on the pros and cons of Define and Inquire, I came up with two designed ideas based on the precedents researched. One is from the first steam engine, and another is from the potato clock (fruit battery). I skipped developing an idea of a second precedent, a solar panel light bulb since I believed it was way too simple and would not be able to put or show enough effort in the product.

An idea generated from “the first steam engine.”

This product essentially displays energy transfer in the first steam engine how it works.

In this mechanism, energy transfer starts from heat energy, turns to gravity potential energy, and ends with kinetic energy. In the process, due to heat and cooling water that is added repeatedly, the water turns to steam when heat is added, and it comes back to water when cooling water is added. Since steam has a considerably larger volume than water, the volume inside the tank repeats, increases, and decreases. Consequently, the piston moves vertically up and down.

By controlling the torch, users can decide whether to expand or contract inner volume. Thereby, users can directly observe how energy transfer works and where it is used.

On the other hand, it is nearly impossible to move considerably in the simplified and reduced structure. It might turn out not to show any operation, which is a complete failure. Besides, it is complicated to build the system.


An idea generated from the “potato clock.”

This idea is mainly originated from the potato clock. The only difference is the usage of electricity. Instead of actuating clock, it runs a carousel that tallies with the objective of this project, to make a device that can entertain children.

The product is designed as the image above, Two (or more if needed) fruits with zinc and copper strips plugged in are connected to a motor inside the base of the carousel. Then, using specially designed gear, a vertically spinning motor horizontally runs the part of a carousel where horses are attached. The gear is called bevel gear, which allows transmitting the direction of mechanical power happened between two shafts.

This device would mostly be made by 3D printing, as it demands high quality and accurate measures.


The decision between two options & the reason

My final selection for the project is a “fruit-powered carousel.”


The reasons for selection are:

-The model of the first steam engine seems to be so complicated that I cannot finish the project in 2 weeks. Fruit-powered carousel has a higher probability of success.

-Considering the objective of the project, fruit powered carousel better fits the purpose as it is a nice toy for young children and at the same time, educates straightforward about energy transfer. Whereas, the model of the first steam engine is too dangerous for young children to play with.


Planning/ Specifying the product

Materials: 3D printer & filament, 1 motor, 5 or more wires, two pieces of fruit (lemon is recommended), glue gun, two copper strips, and two zinc strips.

Techniques: 3D modeling, scientific knowledge about the reduction-oxidation reaction (redox reaction),  some knowledge about electronics.

+additional note: I found out that ISB does not have copper and zinc strips. There was nothing about zinc but for copper, instead of copper strips, copper tapes exist. Through brief research, I figured out that aluminum can play the same role as zinc in the redox reaction. So as an alternative, I am planning to work with taping copper tape and aluminum foil around the thin metal boards instead of copper and zinc strips (supervisor staff told me that it is the only kind of thin metal in Fab Lab).


Steps for creating the device
  1. Model the parts that need to be 3D printed. Send it to the 3D printing request site.
  2. Assemble the 3D printed parts.
  3. Stick horses on the roof and immobilize motor to pillar using a glue gun.
  4. Make lemon battery with copper strips, zinc strips, wires, and lemon.
  5. Connect lemon battery and motor.
DP_G9 Engineering Project

This is a link to a document file with all the images that are supposed to be in this document.

Due to the poor quality of the photos, I am attaching this file.

G9 Engineering Project_Define & Inquire

Define and Inquire


Follow a design process to conceptualize and engineer a device that demonstrates your understanding of energy transfer.

Design, build and refine a device that works within given constraints to convert one form of energy into another format of energy.

  • Show energy transfer
  • Respond to a clear purpose and user
  • Be original, durable, and safe
  • Consider the environment
  • Function
  • Look good


Quick brainstorming:




  • First steam engine

Energy transfer: Heat -> Gravity potential -> Kinetic


The first steam-powered device was a water pump which Newcomen devised. By applying the principle that the volume of water increases hugely when it becomes steam, Newcomen’s device repeats heating water up and cooling down so that the piston would move due to its volume change. But due to its poor efficiency, it was not used right after it appeared in the world. It was developed in 1698 by Thomas Savery. It used condensing steam to create a vacuum that raised water from below and then used steam pressure to raise it higher. Though Newcomen’s first steam engine was not appropriate to use in real life, it is an excellent example of using energy transfer and pressure.


-Clear purpose to teach users about how the first steam engine works.

-Effectively demonstrates the process of energy transfer.

-Looks professional



-Cannot be sure whether it is safe or not.

-When applying this idea, there is a high chance of failure due to its complexity and size.


  • Solar Panel Light Bulb

Energy transfer: Solar Energy -> Electric energy -> Light energy


Solar panel light bulb mainly consists of three components: light bulb, solar panel, and wires. The solar panel converts solar energy to electric energy using the photoelectric effect. The photoelectric effect essentially describes that sunlight produces electrons when it hits an object. Applying this principle, the solar panels can convert solar energy to electric energy. When the electric power is created, it flows through the wire and lights up the light bulb.


A solar panel is the upmost frequently seen renewable energy. Whereas other types of renewable energy require complicated technologies or massive-size producing facilities, solar power is convenient and straightforward to use on various occasions.



-Responds to how energy transfer happens.

-Considers environment, additional knowledge for users about renewable energy.

-Provides light to users.



-Too simple; not challenging.

-Cannot develop innovative and fascinating products when applying solar panels.



  • Potato Clock

Energy transfer: Chemical potential energy -> Electric energy -> Light energy

For the general name of this device, a fruit battery would be more appropriate. This device’s most significantly used principle is the reduction-oxidation reaction called a redox reaction. Each copper and zinc strip is poked in the potatoes and creates a current flow that allows using chemical potential energy inside the potato. This happens as copper has a property that it prefers to lose its electrons, and zinc has the property to gain electrons flowing freely. The current flows and electricity are produced since potato, copper, and zinc strip are connected with wires.



-Clearly shows energy transfer

-Uses renewable energy (eco-friendly)

-Can be applied to various devices by changing electricity usage from the clock to other products.



-Needs some rarely used materials such as zinc and copper strips.

-Cannot be sure whether the power from the fruit battery will run other devices that require higher voltage.



DI_G9 Engineering Project

This is a link to a document file with all the images that are supposed to be in this document.

Due to the poor quality of the photos, I am attaching this file.

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