The Digestive System
Today in science we recreated the human digestive system. It was really fun!

First of all we had to chew up the food in the mouth.

Next the tongue moved the food into the oesophagus (this was messy)!

 The food moved through the oesophagus by an action called peristalsis.

Now the food is in the stomach – here acid and enzymes break down the food further…

After the stomach has churned the food up, it travelled to the small intestine,

where the nutrients are absorbed into the blood.

 The waste food then moves into the large intestine where excess water is absorbed. I think our faces say it all!

The final part is when the waste product comes out in the toilet…

We learnt lots about the digestive system and had great fun! Although some of us found it a bit disgusting...

 Why don’t you have a go at home…
 
  Resources required:

• ? Small banana
• ? Digestive biscuit or Weetabix
• ? Funnel
• ? Small container of water
• ? Small container with very small amount of food colouring in it (preferably green)
• ? Small cup of water
• ? Pipette or syringe
• ? Plastic bag rolled and taped to form a tube (with the bottom cut off)
• ? Plastic sealable bag
• ? Stocking or leg from tights
• ? Small plastic bag with a small hole cut in the bottom
•   Kitchen towels, plastic bin bags, scissors.

 
1. Cover the floor in front of you with newspaper or large bin bags, taped to the floor.
2. Everyday materials will represent each main part (so they will need to use their imagination) and will follow the journey that a banana (moist food) and a biscuit (dry food) would take as they travel through the body, starting at the mouth. Keep everything over the floor covering and use kitchen towels to clean themselves if they need to.
3. A child ‘chews’ the biscuit by placing in their hand and squashing and grinding it
(chewing). Put a few drops of water (representing saliva) into their hands as they are ‘chewing’.
They should end up with a ball of food (bolus) just as we do in our mouths.
4. Chop up the banana with scissors (representing teeth). Push the biscuit and
chopped banana, with their finger (representing tongue), through the funnel and into the plastic bag tube (representing the oesophagus).
5. Use hands to grip and squeeze food hand over hand, down the ‘oesophagus’
into the sealable bag (representing the stomach). Pour the water from the cup (representing
stomach acid) into the bag.
6. Seal the bag (representing closing the valve to the stomach) without much
air in the bag. Ask what happens if there is too much air in the bag (stomach)? They burp/belch
from their mouths. (Note: Wind from the other end is what happens when they have gas in
their intestine!)
7. Have them squeeze the food and water in the ‘stomach’ until it’s fairly liquid and smooth.
While they are doing this ask what is happening and draw out that digestion is taking place
here. At this point explain that if food escapes from the top seal (valve) this is what happens when
a person vomits. However, normally food stays in your stomach for around 6 hours.
8. Next cut a small hole in the bottom of the bag (representing the pyloric sphincter) and
with a partner, pour ‘food’ into only the top 1/3 of the stocking/tights leg (representing the
small intestine). This will take two people. Whilst one cuts the hole, the other holds the leg open
at the top and uses their other hand to squeeze the material together a bit lower down, in order to
prevent the food from going immediately down the whole leg!
9. When they have the food in the top 1/3 of the leg, use the pipette to squirt the water with the
food colouring (representing bile) in and say you are squirting in bile which breaks down fats.
[Note: This part is particularly messy!]
10. Have them squeeze the food through the stocking (the small intestines). The water coming out
through the walls represents the nutrients going to the rest of the body.
11. At the end of the stocking leg is the foot (large intestine). Explain there are ‘good’ bacteria here
and last bits of water and nutrients are absorbed into the body. Teacher cuts a hole in the end as
the food approaches.
12. Next squeeze the remaining food into the small plastic bag with a small hole cut in the bottom (representing the rectum and anus).Then have them squeeze their waste through the hole in the cup into a bowl (toilet). Make sure everyone is clean and all the ‘mess’