How to model digestion using tights

  • Digestion is the process of the food we eat being broken down into substances that our bodies can use.

  • The digestive system provides our body with the energy it needs.

  • It is vital that our body gets the correct amounts of each food group in every meal.

Have a go

A picture showing what you need to model digestion

Click to see a step by step slideshow.

1 of 10

What is digestion?

Digestion is an important process in the human body. It helps us get the nutrients our body needs to stay healthy.

Digestion happens in the digestive system, which begins at the mouth and ends at the anus.

What nutrients does our body need?

A balanced diet provides our body with the correct amount of each food group, so that our body can function at its best:

  • Carbohydrates
  • Lipids (fats and oils)
  • Proteins
  • Vitamins
  • Minerals
  • Dietary fibre
  • Water

What happens during digestion?

Different things happen to food as it passes through the digestive system:

  • Food is broken down mechanically and chemically in the mouth.
  • The smaller molecules of food pass into the stomach and small intestine, where they continue to be broken down.
  • Digested food is absorbed into the bloodstream in the small intestine.
  • Excess water is absorbed back into the body in the large intestine.
  • Any undigested food passes out of the anus as faeces (poo) when we go to the toilet.

How can we model this process?

The clear plastic bag represents the stomach which is a large muscular sac that contains hydrochloric acid, it is able to churn the food, mixing it with the acid so that it can be broken down into even smaller molecules.

The food is then poured into the tights, this represents the small intestine inside the body. This is where the nutrients from the food we have eaten is absorbed.

The small intestine is well adapted for digestion: it has thin walls, making it easy for food molecules to pass through into the blood stream.

The last stage of digestion involves the large intestine that absorbs water and any remaining nutrients from the small intestine. Once this has been done the waste products are then excreted from the body as faeces.

Where next?

Discover more about this topic from around Bitesize.

Revise - Digestion
revision-guide
What is digestion?
What is a healthy diet?
More from KS3 Biology