Bicarb bloating

What's this Science Bite about?

Try our science experiment - bicarb bloating - to see what's going on when your stomach produces more acid than you need for it to work effectively!

After food is mixed with saliva in the mouth it passes through the oesophagus and enters the stomach where it is further broken down by the combined effects of the acid environment and a number of enzymes. The acid environment also destroys any harmful parasites or bacteria that are ingested along with food.

Stomach acid is produced by cells lining the stomach and is produced for a number of reasons.

When we see, smell, taste or even think about food our brain sends signals to the stomach to prepare it for the arrival of food. When the food enters our stomach more acid is released. The process of eating stretches your stomach which also causes more acid to form. When food leaves the stomach new signals are sent which stop more acid being released.

Sometimes your stomach produces more acid than you need and you may experience gastric reflux which can cause a burning sensation in the chest and oesophagus, otherwise know as "heartburn."

One of the ways to treat acid reflux is to take an antacid designed to neutralize the stomach acid.

Try the experiment and see what's going on!

Always remember to ask your parent or guardian to help you.

What you'll need

Try the bicarb bloating experiment - you'll need bicarbonate of soda, a conical flask, vinegar, a balloon and a spatula

  • Bicarbonate of soda (about 20g)
  • Concical flask or bottle
  • Vinegar (about 200 ml)
  • Balloon
  • Spatula or spoon

How to do the experiment

Follow the instructions in the video below.

Can't see the video above? Watch it on Youtube.

icon Bicarb Bloating (563.33 kB)

  1. Add the bicarbonate of soda to the flask until the bottom is covered.

  2. Stretch the balloon and blow it up. Let the balloon deflate and stretch it over the neck of the flask.

  3. Turn the flask upside down to allow the bicarbonate of soda to fall into the balloon.

  4. A conical flask containing bicarbonate of soda with the balloon stretched over the neck of the flask
  5. Add 200 ml of vinegar to the flask.
  6. Stretch the neck of the balloon over the neck of the flask and allow the bicarbonate of soda to hang freely.

  7. A conical flask containing vinegar and a balloon containing bicarbonate of soda stretched over the neck of the flask
  8. Lift the balloon completely upright so that the bicarbonate of soda falls into the vinegar.

  9. The balloon starts to inflate as the bicarbonate of soda falls into the vinegar and produces carbon dioxide gas.
  10. Stand back and enjoy the show!

Find out more...

When vinegar (an acid) comes into contact with bicarbonate of soda (an alkali) a neutralization reaction takes place.

Chemical reactions always form new products. In this experiment one of the products is carbon dioxide gas. Gases take up more space than solids or liquids so the balloon expands.

When you take an antacid this same reaction takes place in your stomach. The bubbles of carbon dioxide produced in the reaction can make you feel bloated.

You can get rid of the excess gas by burping or farting!

Visit BodyWorks at Glasgow Science Centre - an interactive exhibition all about human health and wellbeing in the 21st Century.

Curriculum Links

Body Systems and Cells

SCN 2-12a

Chemical Changes

SCN 2-19a/ 3-19a/ 3-19b


Glasgow Science Centre