Bath bombs consist of a wide range of ingredients, including bath salts, food coloring, fragrance, citric acid, sodium carbonate, and other components. Bath bombs ‘fizz’ when water inclines to trigger a reaction between an acid and a base (neutralizing substance). Many bath bombs contain citric acid, and sodium carbonate, which incline to have a weak base. This reaction helps to break up the bath bomb, releasing fragrances, detergents, and oils. Furthermore, when a bath bomb contacts with water, the sodium carbonate, and citric acid react to make carbon dioxide bubbles and gas that defines the product. This is an example of a chemical reaction. The kinetic energy associated with particles increases or decreases with temperature. As such the more energy produced within a practical, the more It bounces. The more it bounces around, the more likely it will collide with other particles. Therefore, for this reason, the rate of reaction hugely increases the temperature. However, as a contrast, it does also decrease the temperature.

AIM:  To investigate how temperature affects the reaction of hydrochloric acid and bath bombs to produce carbon dioxide.

HYPOTHESIS:  The higher the temperature, the greater volume of carbon dioxide produced.


Independent Variable: Temperature (C)

Dependent Variable:  Volume of Carbon Dioxide (cm). Carbon Dioxide is measured through the use of a balloon and string. After the balloon is filled up with carbon dioxide after a minute, the string is used to check the diameter of the balloon in cm. 

Controlled Variables:

Controlled variablesHow they will be controlled?Why do They Need to be Controlled?
  Hydrochloric acid (25m)  This will be controlled by making sure to use a 25m measuring cylinder.If the concentration of the Hydrochloric acid varies, it can then speed up or slow down the reaction, due to being more or fewer collisions as a result of it.
Bath bombs (5g)  This will be controlled by using a measuring scale.More or less bath bomb power could result in some having more surface area than others. Therefore, making some react faster and collecting more carbon dioxide than others.
Surface area of bath bombs  By making sure they are crushed and in the powder form.Lumps or blocks of bath bombs will result in there being less particles being exposed, resulting in lower reaction rates. Whereas, if the bath bombs were added as fine powder, more particles are exposed, making them collide often and increasing the reaction rate overall.
Concentration of acid (1.0)  By making sure toIf the concentration was higher or lower, it could result in a faster or slower rate of reaction. Therefore, providing inaccurate and unexpected results. 
Time (1 MIN)Using a stopwatchIf some balloons were left longer than others, It would lead to extra carbon dioxide being collected, which could result in all temperatures having the similar volume of carbon dioxide being collected


Potential hazards of your practical?What is the harm it can cause?How will you manage the hazard?
Spilling acid  or hot water Coming in contact with the body and causing burns or other physical harm. Can damage the surroundings, for instance, appliances, and could also get in contact with other chemicals. Can burn skin and cause major damage if spilled on an electrical appliance.Wearing safety PPE ( glasses, apron, and gloves) Clearing the surroundings and making sure electrical appliances or objects, in general, are kept away from the area.
Bath bomb powder getting into eyes or mouthCan burn the eyes or cause irritation within the eyes and oral irritation. Moreover, could also lead to other disturbances like nausea, vomiting and diarrhea. Wearing safety PPE. Making sure bath bomb powder is in a closed container. Regularly washing If gloves, not wornMaintaining distance from the beaker when the power is poured in.
Dropping or breaking materials. ( Eg, beaker, conical flask etc.Can cause psychical harm to the person if stepped on the glass piecePlacing the beaker in a confined area where it’s not touched or moved. Similarly, making sure that all equipment are kept close to the wall where they cannot easily fall down the desk.


  • 3x beaker
  • 25ml Measuring Cylinder 
  • Safety PPE
  • 3x petri dishes
  • 3x plastic tubs
  • Hot water & Room temp water
  • Ice  
  • 15 grams bath bombs 
  • 6x balloons 
  • Stopwatch 
  • String 
  • Measuring tool (i.e. ruler and kitchen scale)
  • Hydrochloric acid 1.0M (150ml total)


  1. Place 1 beaker in a tub filled with ice cubes, then place another filled with hot water, finally leave the 3rd beaker as it is. 
  2. Collect 25ml of 1.0 hydrochloric acid in a 25ml measuring cylinder.
  3. Collect and add 5g of bath bombs into three different petri dishes.
  4. Empty each petri dishes with 5g of bath bombs into all three beakers. 
  5. Get a balloon and stretch the opening.
  6. Pour the Hydrochloric acid from the measuring cylinder into a beaker.
  7. Quickly place a balloon on top of the beaker, making sure the gas does not escape.
  8. Time the reaction for a minute using a stopwatch.
  9. Measure the circumference of the balloon using a string and a ruler. 
  10. Repeat steps 1-9 1 more time.


Temperature (OC)Volume of Carbon Dioxide  (cm)
Trial 1Trial 2Average
Room21 17  19
Hot 1719.518.25


The results derived from the experiment show that the average balloon size for temperatures like iced inclined to 19, room was 19 and hot was 18.25. These results however incline to highly differentiate from the expected results. As the particle theory states that as temperature increases, the particles in a reaction then have more kinetic energy, which in turn causes them to move faster and collide more. Hence, this should usually mean that the width of the balloon in the hot water tub should incline to be greater than the balloons in ice and room temperature, due to there being fewer collisions happening because of lower temperatures the breakers are placed in. The inconsistencies could be due to various random and systematic errors being present.


 What is the error?Explain how this error could’ve affected the results?How could it be improved?
Systematic Errors   
 Flask sizeIf the flask size was smaller, then the particles can collide more, having a faster reaction.  Similarly, if the flask was too big, then the reaction will take longer due toMaking sure the flask size used for all three temperatures are the same.
 Calibration of scaleIt could provide an inaccurate weight for bath bombs. So, some could have more bath bomb powder than others, resulting in a faster reaction rate.Making sure the scale is calibrated to grams (g) and the right amount is added.
 Concentration of acid-  we don’t’ know if the concentration of the hydrochloric acid is 1.0If the concentration of acid is higher or lower, it can affect the reaction rate, as some would have a faster reaction/ more carbon dioxide than others.It could be avoided by checking the concentration of the acid before doing the practical.
Random Errors   
Gas leaking between the reaction and putting the balloon on.It would provide inaccurate results for that temperature and will also seem that the reaction has happened to the fullest.This error could be improved by making sure the balloon is stretched forehand. So that now there’s minimal gas leakage from when putting stretching it and putting it on.
 Losing bath bomb on the benchThis could mean that not all have 5g of bath bombs in them, resulting in inaccurate or unexpected results as some might have a greater volume of carbon dioxide due to the faster reaction rate.Making sure the bath bomb is carefully poured into the breaker first to prevent rushing it.
 Timing for too longThis could lead to extra gas being collected in the balloon which could result in a similar volume of carbon dioxide sizes within all three temperatures. Hence, providing inaccurate results overall.Making sure to be aware of the time and make sure to stop the time 1 minute.

Random errors- As the number of random errors increases the reliability decreases and vice versa. 

It is important to repeat the experiment after noting the systematic errors, since it inclines to then help provide more accurate results, knowing that they won’t occur again.


The aim of this practical is to determine the effect of temperature on hydrochloric acid and bath bombs to produce carbon dioxide. The findings inclined to highly vary from the hypothesis. This was due to all temperatures producing the same averages. The contrast of results derived might be due to the random and systematic errors.


Davies, E 2018, What causes bath bombs to fizz?, BBC Science Focus Magazine, BBC Science Focus Magazine, viewed 25 November 2021, <>.

Science Buddies 2014, Sudsy Science: Creating Homemade Bath Bombs, Scientific American, viewed 25 November 2021, <>.

author avatar
William Anderson (Schoolworkhelper Editorial Team)
William completed his Bachelor of Science and Master of Arts in 2013. He current serves as a lecturer, tutor and freelance writer. In his spare time, he enjoys reading, walking his dog and parasailing. Article last reviewed: 2022 | St. Rosemary Institution © 2010-2024 | Creative Commons 4.0

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