SILVER

Edible Water Bottles Used as Water Balloons - Does Size Matter?

The project focused on comparing latex water balloons with plant-based edible water bottles re-purposed as water balloons, of various sizes.
Myles Krygier
Grade 7

Hypothesis

If I drop different sizes of edible water bottles from different heights (Experiment 1) or squeeze them (Experiment 2), then the 60ml water bottle will be the best water balloon because it will be strong and large enough to act like a latex water balloon.

Research

Chemical Reaction

The process to make edible water bottles is a simple chemical reaction. It begins with two main ingredients: sodium alginate (a material made from a type of seaweed called brown algae) and a calcium solution (I used calcium lactate). As soon as the sodium alginate and the calcium lactate bath are combined, the calcium reacts and forms a gel like substance. The sodium alginate forms a sphere when placed in the calcium lactate bath as a result of the reaction. In learning about these spheres, I've found they have had applications for food products in the past, and there are possibilities for the chemical reaction to be used in the future with 3-D printing as described in an article titled "Molecular Gastronomy and the art of Reaction-based 3D Printing"  (Mire, 2014).

In my experiment, I used distilled water because Calgary water contains calcium and that would affect the creation of edible water bottles. It would have reacted with the sodium alginate solution and ruin the mixture. In 2019, according to the City of Calgary data, Calgary tap water contained on average 55 mg/L of calcium. (City of Calgary, 2019)

 

Surface Tension

Surface tension means that the layer on the outside of the liquid has a stronger bond than the liquid on the inside. Surface tension forms liquids into a sphere. The molecules can support a minimal amount of weight before too much force breaks the bonds within the liquid. The molecules involved in surface tension are attracted to eachother and this is called cohesion (Kiddle Encyclopedia, 2020).

If you were to put a sphere of liquid in space there would be no gravity or other forces to interfere with the surface bonds. That would mean that the liquid would stay in a spherical shape (Kiddle Encyclopedia, 2020).

A sphere shape allows for the least amount of surface area possible on a water droplet. When droplets have an increase in volume, they are impacted more by forces such as gravity and they begin to deform (Institute of Physics, 2005).

 

Environmental Impact

Edible water bottles are environmentally friendly. Notpla, the company that makes plant-based packaging say that it only takes four to six weeks to decompose and are non-toxic because they are made of plant material. According to the WWF, regular water bottles can take up to 450 years to decompose. Plastic is very bad when it gets into our ecosystem. Around the world, over 240 wildlife species have swallowed plastic which often results in injuries and death (WWF-Australia, 2018).

According to the National Observer, Canadians use more than 2 billion water bottles every year. About half a trillion water bottles are made globally each year. Only 9% of all plastics have been recycled (Barlow, 2020). This is a reason to make edible water bottles. 

When talking about latex water balloons, some animals that are impacted by these types of balloons are birds, whales, sea turtles, bighorn sheep and other wild and domestic animals. An animal can starve after eating a balloon because it blocks it's intestines. Even though latex balloons may be marked as biodegradable they are full of chemicals and take many years to break down (Balloons Blow, 2012). 

There is a difference between biodegradable material and compostable material. Biodegradables are often still plastic that have microorganisms added to break down the plastic. Compostables are made of natural plant materials, and do not produce any toxic material. Biodegradables get broken up into small pieces which can be hundreds (microplastics). It makes it extremely difficult to pick up and stays in the environment (Krosofsky, 2020). The edible water bottles are compostable and breakdown into organic material.

 

Discussion with an Expert
Dr. Shawn Loo, PhD (Contaminant Hydrogeology)

What effect do you think having edible water bottles of different sizes might have on their strength?

The polymer that is created will likely be stronger with a smaller amount of liquid inside. This is because as the volume of water increases the surface area tension would decrease.

Do you think using edible water bottles is a good alternative to plastic water bottles or even latex water balloons?

I do not like water bottles of any type and do not think they are necessarily needed. However, in some applications (like the example of the marathon) where individual serving sizes are needed it is better than paper or plastic cups.

What impact do latex water balloons have on the environment and our water systems?

Latex balloons are very bad for the environment. They make their way into water systems and are swallowed by animals that can choke on them. The latex does degrade but it takes a very long time.  Plastic water bottles take even longer. It would be good to have an alternative that is compostable.

We also talked about experiment design and some ways to measure the strength of the edible water bottles.

Variables

Independent variables: latex water balloons and edible water bottles of different volumes (5 ml, 15 ml, 30 ml and 60 ml).

Controlled variables: surface the bottle is dropped on, the kitchen scale and the plate to push down on it.

Dependant variables: the height they are dropped from to break. The grams on the scale measuring the weight placed on them.

Procedure

Making the Edible Water Bottles (Balloons)

Materials

  • 1 gram of sodium alginate
  • 5 grams calcium lactate
  • Big bowl with 4 cups of water
  • Smaller bowl with 1 cup of drinking water
  • Bowl with any amount of water
  • Immersion blender
  • Measuring spoons/cup (size of the finished bottle)
  • Big slotted spoon, whisk 
  • Digital Kitchen scale

Procedure

  1. Pour 1 gram of sodium alginate in the bowl with 1 cup of water.
  2. Mix the sodium alginate in the 1 cup of water with an immersion blender.
  3. Set the mixture aside for 15 minutes to get rid of the air bubbles.
  4. Pour 5 grams of calcium lactate in the bowl with 4 cups of water (you may need to crush tablets into powder if it did not come that way).
  5. Mix well and make sure that the calcium lactate is completely dissolved.
  6. Scoop up some of the sodium alginate solution with the measuring spoon or cup. The amount of sodium alginate solution will be the size of your finished water bottle.
  7. Put the scoop of sodium alginate solution gently into the calcium lactate bath.
  8. Gently stir the solution for 15 minutes.
  9. Use the slotted spoon and take out your water bottles.
  10. Put the water bottles in the bowl with any amount of water for about 5 to 10 seconds to settle the reaction.
  11. Gently remove with a slotted spoon.

 

Balloon Drop Test (Experiment 1) and Balloon Squeeze Test (Experiment 2)

Materials

  • 24 edible water bottles of various volumes (6 of each 5 ml, 15 ml, 30 ml and 60 ml)
  • 6 latex water balloons
  • Measuring spoons and cups
  • Measuring tape or ruler
  • Kitchen scale
  • Plastic food lid
  • Large tub

Procedure - Balloon Drop Test

  1. Fill three latex water balloons with 120 ml of water.
  2. Hold the water balloon at a height of 5 cm.
  3. Drop onto the bathtub surface.
  4. Record whether the water balloon broke at this height. If it did not, repeat by lifting it up 10 more centimetres. Continue this process until the water balloon breaks. Repeat this process for all three of water balloons.
  5. Make 12 edible water bottles – (3 of each volume – 5 ml, 15 ml, 30 ml, 60 ml).
  6. Hold the 5 ml edible water bottle at a height of 5 cm.
  7. Drop onto the bathtub surface.
  8. Record whether the edible water bottle broke at this height. If it did not, repeat by lifting it up to 10 centimetres, and continue up the measuring tape. Continue this process until the water bottle breaks. Repeat this process for all three of the 5 ml edible water bottles
  9. Repeat the procedure for the edible water bottles of different volumes.
  10. Calculate the average height when the water balloons broke and the average height when the water bottles broke for each volume of water.

Procedure - Balloon Squeeze Test

  1. Fill three latex water balloons with 120 ml of water each.
  2. Place a water balloon on a kitchen scale. 
  3. Place a plastic lid on top of the water balloon. Use your hand to apply downward force on top of the lid. Make sure to slowly apply this pressure to the water balloon.
  4. Record the number of grams displayed on the scale when the water balloon breaks.
  5. Repeat this process for all three of water balloons.
  6. Make 12 edible water bottles – (3 of each  – 5 ml, 15 ml, 30 ml, 60 ml)
  7. Place the 5 ml edible water bottle on a kitchen scale. 
  8. Place a plastic lid on top of the water bottle. Use your hand to apply downward force on top of the lid. Make sure to slowly apply this pressure to the water bottle.Record the number of grams displayed on the scale when the water bottle breaks.
  9. Repeat the procedure for the edible water bottles of different volumes.
  10. Calculate the average weight when the water balloons broke and the average weight when the water bottles broke for each volume of water.

Observations

Making the Edible Water Bottles

  • I added food coloring to the sodium alginate mixture so I could see the water bottles better while I was making them at first. 
  • As soon as I placed the sodium alginate solution in the calcium lactate bath it formed a sphere right away.
  • By stirring it gently it helped the reaction happen evenly and the edible water bottle hold its shape. When I stirred it too fast the sphere would break or become deformed.
  • The clean water stopped the reaction by rinsing the water bottle. 
  • After the water bottles popped the shell would turn into an algae slime. I tried eating one of the water bottles and I have to say it was absolutely disgusting.

The Experiments

Balloon Drop Test

Latex water balloons- It was impossible to break these water balloons because they just kept bouncing all over the place. After I tried to add a little bit of force they still were not breaking. I could not gather any data for latex water balloons.

Edible balloons- I can tell that the edible water balloons are a lot weaker than the latex. They did not pop but instead when they broke water would just leak out. I was able to drop the smaller ones from a higher distance without them breaking.

Balloon Squeeze Test

Latex water balloons - I had to use a bathroom scale to measure the weight pressing down because the kitchen scale range was too small. If I did not push enough then the balloons would go into a funny shape.

Edible water balloons- I observed that they would burst a lot sooner than latex balloons because their shell was a lot weaker. The larger edible water balloons seem to burst under less pressure than the smaller ones.

 

 

Analysis

Balloon Drop Data

Balloon Type and Size

Test 1

Test 2

Test 3

Average

Latex Balloon (120 ml)

No data

No data

No data

No data

Edible Balloon (5 ml)

40 cm

50 cm

50 cm

46 cm

Edible Balloon (15 ml)

20 cm

20 cm

20 cm

20 cm

Edible Balloon (30 ml)

10 cm

20 cm

20 cm

16 cm

Edible Balloon (60 ml)

10 cm

10 cm

5 cm

8 cm


Balloon Squeeze Data

Balloon Type and Size

Test 1

Test 2

Test 3

Average

Latex Balloon (120 ml)

5,878 g

12,701 g

16,783 g

11,787 g

Edible Balloon (5 ml)

542 g

418 g

690 g

550 g

Edible Balloon (15 ml)

238 g

466 g

 343 g

349 g

Edible Balloon (30 ml)

299 g

290 g

245 g

278 g

Edible Balloon (60 ml)

140 g

178 g

200 g

172 g

 

Latex and Edible Water Balloon Drop Graph (height dropped [cm])

LB - Latex Balloon, EWB - Edible Water Balloon

 

Latex and Edible Water Balloon Squeeze Graph (weight used [g])

LB - Latex Balloon, EWB - Edible Water Balloon

Conclusion

My hypothesis was incorrect as I overestimated the strength of the edible water balloons - especially at 60 ml. I underestimated the strength of latex water balloons and did not realize how strong they really are. It was impossible to break the latex balloons by simply dropping them. I also had to use a bathroom scale to measure the weight pressing down to break the latex balloons. I discovered that the smaller the edible water balloon, the stronger it is. For example, the edible water balloon with 5 ml of water could withstand a higher drop then one with 60 ml when I was righting my hypothesis I did not take this into mind.

The larger the balloon the easier it broke. In the Balloon Squeeze test the smaller balloon also withstood more weight then the larger balloon. In my results the graphs show the difference between each size of balloon. The trend is that the smaller the balloon the more force it can handle.I think this is because the surface tension of the water is weakened when there is a higher volume of water which pushes harder against the algae shell.

In order for a larger edible water bottle to be used like a regular latex water balloon the shell would have to be stronger. 

In the future I could try the following things to see if they would improve the strength of the edible water balloon maybe the outcome of the experiment would of changed and my hypothesis would be right if I did these things -

  • I could change the amount of ingredients in the water.
  • I could leave the edible water balloon in the calcium lactate longer.
  • I could try to use calcium chloride instead of lactate because I read it could give a stronger shell.

 

 

Application

Could I use edible water bottles as water balloons?

I personally don't think that edible water bottles are able to be used as water balloons because the shell is too thin and the algae gel is very messy. I think with some more research I could develop a better, stronger plant based alternative to latex water balloons.

How are edible water bottles used now and how could they be used in the future?

According to Notpla, edible water bottles are used as portable water supplies for marathons to keep athletes well hydrated. They are also being developed for condiments (holding your ketchup or mustard at fast food restaurants). They can also hold other liquids like soap. It seems that the current issues with these types of plant-based packaging is their strength, capacity and storage.

In the future, with more development, these edible water bottles could replace plastic water bottles, latex water balloons, food packaging and cleaning and personal hygenie containers.

If we used these instead of plastic packaging we could save the lives of animals and marine species across the globe, reduce the amount of plastic waste in oceans and landfills, and have packaging that is compostable and returns to the earth.

 

Sources Of Error

In my first trial - I  did not put enough Sodium Algainate in the mixture. I stirred the mixture for a lot less time than I had to and the balloons were weak.

When I was doing the experiment some of the edible water balloons would break when I was picking them up because I squeezed them too hard or dropped them before conducting the experiments.

Citations

Barlow, Maude. "What good is a single-use plastics ban if it doesn't include water bottles?" Canada's National Observer, Observer Media Group, 9 October 2020, https://www.nationalobserver.com/2020/10/09/opinion/what-good-single-use-plastics-ban-if-it-doesnt-include-water-bottles.

Krosofsky, Andrew. "Biodegradable vs. Compostable: What’s the Difference?" GreenMatters.com, Green Matters, 9 November 2020, https://www.greenmatters.com/p/biodegradable-compostable-difference.

Mire, Charles. "Molecular Gastronomy and the art of Reaction-based 3D Printing." 3DPrint.com, 3DR Holdings, 24 June 2014, https://3dprint.com/7166/molecular-gastronomy/.

"Balloons Blow...Don't Let them Go!- English Fact Sheet." Balloons Blow.org, Balloons Blow, Inc., February 2012, https://balloonsblow.org/fact-sheet/.

"City of Calgary Glenmore Water Treatment Plant Summary." Calgary.ca, City of Calgary, 31 December 2019, https://www.calgary.ca/content/dam/www/uep/water/documents/water-documents/annual-glenmore-water-treatment-plant-summary-2019.pdf.

"Forces and Motion, More surface tension effects." Spark - Institute of Physics, IOP, January 2005, https://spark.iop.org/more-surface-tension-effects#gref.

"Ooho! Edible and biodegradable. The alternative to plastic." Notpla.com, Notpla Ltd., October 2020, https://www.notpla.com/products-2/.

"Surface tension Facts for Kids." Kiddle Encyclopedia, Kiddle.co, December 2020, https://kids.kiddle.co/Surface_tension#Liquid_surface.

"The lifecycle of plastics." WWF, WWF-Australia, 19 June 2018, https://www.wwf.org.au/news/blogs/the-lifecycle-of-plastics#gs.wjxnge.

"WWF releases report on global plastic pollution crisis." WWF, WWF-Australia, 5 March 2019, https://www.wwf.org.au/news/news/2019/wwf-releases-report-on-global-plastic-pollution-crisis#gs.wjy68s.

 

Acknowledgement

I would like to thank Dr. Shawn Loo PhD for helping me in this project and giving me some vital information for the experiment. I would also like to thank my mom for buying all of the supplies needed.