Year 4 Science - Ready, Steady, Digest!

Today, the children recapped their prior learning about human organs and revisited the journey of food through the digestive system. We reminded ourselves of key organs and new scientific vocabulary, thinking carefully about how food moves through the body and changes along the way.

To bring the learning to life, the children took part in an energetic “Ready, Steady, Digest!” activity. They followed step-by-step instructions to demonstrate how a banana sandwich is digested, turning the classroom into a buzzing science lab! Working in teams (with some friendly competition), the children were fully engaged and eager to see whose sandwich would be “best digested”.

First, the children finely cut their banana and chocolate spread sandwiches using knives and forks. This represented the incisors at the front of the mouth cutting and tearing food. Next, they used potato mashers to mash the sandwich, modelling the grinding action of the molars at the back of the mouth.

A small amount of “saliva” (water mixed with red-coloured syrup) was added, and children learned that saliva contains enzymes, which start digestion in the mouth. They were careful not to add too much, discussing why digestion needs balance.

The mashed sandwich was then spooned into a clear plastic bag to represent the stomach. Green-coloured lemon juice or vinegar was added as stomach acid, and the children enthusiastically squeezed and churned the mixture, showing how the stomach mixes food with chemicals to release nutrients.

Once the mixture became sloppy, it moved into the intestines, modelled using a pop sock or tights. The children squeezed out the liquid, collecting it in a bowl to represent water being absorbed and later processed by the kidneys and bladder. There were lots of fascinated (and slightly disgusted!) reactions as they observed what was happening.

Finally, the remaining solid mass was squeezed out, showing how waste leaves the body at the end of the digestive journey.

Afterwards, children worked in pairs to explain the digestion process to each other, confidently using scientific vocabulary. To record their learning, they created a flow chart showing the sequence of digestion from mouth to exit, clearly demonstrating their understanding.