The Alka-Seltzer Challenge? Due Date: ________________
“To invent, you need a good imagination and a pile of junk.” -Thomas Edison (If it snows, project due the next
day we are in school.) Objective:
Design a gadget that accomplishes one (or more!?) of the following tasks:
Light a match Cause something to change color Blow out a candle
Pop a balloon Lift a 500 gm object at least 5 cm Turn on a light bulb
1) The gadgets driving force must come from a chemical reaction: either Alka-Seltzer and water or
baking soda and vinegar. You choose.
2) If you use Alka-Seltzer? (or some similar produce), you may only use one tablet to run the
device. (Preferably you will use less than one tablet.) If you use baking soda and vinegar, you will
be limited to 30 ml (2 tbsp) of baking soda and 240 ml (1 cup) of vinegar.
3) All development and testing must be done at home. You are responsible for any equipment and
supplies. Testing, re-testing, redesigning, and practicing are EXTREMELY IMPORTANT.
As Thomas Edison once said, “Genius is 1% inspiration and 99% perspiration.”
4) The device must be automatic: that is, it must accomplish the task without your touching it in any
way. Obviously the device must be handled to get it set up and add the reactants, snap on a lid,
etc. But then it must be left untouched to perform the task. So that there is no question about this,
there must be a 5-30 second delay from the time the device is sealed shut and let go of to the time
the task is accomplished.
5) The device must be safe: any potential risk or hazard can cause your device to be disqualified.
(Example: your device sends a sharp object flying across the room…) 6) The device must be self-supporting and self-contained. In other words, you should not have to
hold something or tape it to the table or ask the teacher for a ring stand or a pile of books, etc.
Also, no messy splashes all over the lab benches or the floor!
7) The device should be made with “demonstratability” in mind. Have everything clear and visible. It should be obvious to anyone watching what the device is doing and why.
8) Creativity is the essence here; so is visual appeal! Top priority is making a device that works,
but making it look good is also worthwhile.
Example of a top-notch project:
When it is her turn, Sara takes her project to the designated table at the front of the room. She
quickly and quietly sets up her project. Anything she could have done ahead of time was already taken care of at home. Her set-up just involves pouring some pre-measured vinegar into a cup and positioning a marble on top of a bottle… Then, at the teacher’s signal, she pours the pre-measured baking soda through a funnel, snaps the lid in place and steps back. The class watches. The device is so well-made – everything is clearly visible: the working of the device, the cause and
effect, the whole chain of events – all so self-explanatory and clever…and the device is nicely decorated too! 9.3 seconds later the balloon pops. The class gives Sarah a standing ovation for
her ingenuity and craftsmanship. Grade: 100/100.
Example of a rather poorly done project:
When it is his turn, Bill takes his project up to the table, spends three noisy minutes duct-taping a
shoe box to the table and asking the teacher for some vinegar, a baggy and a candle. Then at the nod from the teacher, he pours an arbitrary volume of vinegar into the baggy, throws in 17 Alka-Seltzer? tablets, and holds it closed with his fist. 0.3 seconds later, the bag ruptures, splashing
liquid all over the table and the floor… Ironically, the only thing that stayed dry was the candle
which he was holding with his other hand beneath the bag, but which he’d forgotten to light in the
first place!!! Ben stays after school to remove the duct tape goo from the table top. Grade: 10/100
Alka-Seltzer? Challenge Grading Criteria: Total possible points: 100
- The device has no chance of working. 65 points
- The device does not work. There was some good thinking,
but not much effort was put into perfecting it. 70 points
- The gadget comes close to working but doesn’t quite accomplish
the task it was designed to accomplish. 80 points
- The device works well but requires manual intervention. 80 points
- Gadget performs the primary task it was designed to do. 95 points
- Bonus points for additional tasks. Up to 5 points per task
- Bonus points for creativity. Up to 10 points
- The appearance of the gadget shows very little
thought or effort. Up to 10 points off
- There was no delay between sealing the container
and accomplishing the task. Up to 10 points off
- There was a delay, but it did not last the required
5-30 seconds. Up to 5 points off
- More than one minute required for set-up. Up to 5 points off
- Some mess was made and not contained during
the demonstration. Up to 5 points off
- Limited visibility of the workings of the device. Up to 5 points off
This will be presented in class and will be worth a test grade.
Aside from building the device and demonstrating it in front of the class, you are required to turn in
a type-written paragraph that explains the entire process by which the device works. The title
should include a creative name for the device. Also include, on a separate sheet of paper, a
neatly-done drawing of your device that includes labels of the components. This write-up is worth an additional test grade.
Adapted from Flinn Scientific Foundation