Brilliant Bile

What's this Science Bite about?

See how bile can help the digestion process in this science experiment to try in the classroom or at home.

Bile is a bitter tasting, dark green to yellow brown fluid. It is an essential part of digestion and allows the body to absorb fat.

Production of bile is just one of over 500 functions of the liver, which is the largest internal organ of the body.

Once the bile is produced it is stored in the gall bladder until our body needs it.

As partially digested food passes from the stomach to the small intestine, bile is secreted to aid digestion.

Try the experiment and see what's going on!

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

What you'll need

What you'll need for the Brilliant Bile demo - cooking oil, water with some food colouring, washing up liquid and 2 glass bottle with lids.

  • Cooking Oil
  • A glass jug containing 500 ml of water with 4 or 5 drops of food colouring added (use any colour except yellow)
  • Washing up liquid
  • 2 bottles with lids

How to do the experiment

icon Brilliant Bile (573.58 kB)

  1. Add water (containing the food colouring) to each of the bottles until they are about ½ full.

  2. Add the water to the glass containers so they are each half full
  3. Add oil to the bottles. The oil will form a layer on top of the water.

  4. Add the oil to the bottles. The oil will form a layer on top of the water.
  5. Add a generous squirt of washing up liquid to one of the bottles.

  6. Put the lids on both bottles and give them a vigorous shake.

  7. Put the lids on both bottles and give them a vigorous shake
  8. Stand back and enjoy the show!

Find out more...

The bottle with oil and water begins to separate almost immediately. The bottle with oil, water and washing up liquid stays mixed for much longer.

You have made an emulsion, a mixture of two liquids that normally would not mix (immiscible)

Soap molecules have two ends. One end loves water (hydrophilic) and the other fears water (hydrophobic). When you add soap to the oil and water the hydrophilic end bonds to the water and the hydrophobic end bonds to the oil.

Like soap, bile has both hydrophobic and hydrophilic sections. The bile emulsifies the fat in the partially digested food which increases the surface area of the fats allowing for easier absorption into the blood stream.

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

Curriculum Links

Body Systems and Cells

SCN 1-12a/ 3-12a


Glasgow Science Centre