The Journey of Food

In science this half-term, Year 4 have been learning about the journey of food through the digestive system. Year 4 took park in ‘Ready, Steady, Digest!’ and had the pleasure of showing off their science skills to our heads for the day, Mr Varaitch and Mr Patel!

Using a plastic bottle, water and vinegar, the children explored the different functions of the different parts of the digestive system and how a banana sandwich would be digested. 

First we broke up the bread with our fingers. This represented the actions of the teeth in the front of the mouth cutting and pulling the food. We then mashed up the banana with our fingers. This represented the grinding action of the molars at the back of the mouth. After this we added a dash of ʻsalivaʼ (water). We learnt how saliva contains chemicals called ʻenzymesʼ which start the digestive process off. We then added vinegar to represent the stomach acid and shook our bottles. We did this because food in the stomach is churned up to mix it with all of the chemicals the body produces. This helps to remove all of the nutrients food provides so that our body can make use of them. 

Finally we explored what happens to the food once it leaves the stomach. We learnt that the food enters the intestines where water and nutrients are absorbed. The water is then eventually processed by the kidneys, exiting the body via the bladder, and the food, which is now a more solid, cohesive mass, exits the body via the rectum. 

And on that note, we’ll leave you with the photos!!

Having explored the functions of the human digestive system, we then looked more closely at where the digestive process begins – in the mouth. 

First we explored a plaster cast of Mrs Blanshard’s mum’s lower jaw and so lower set of teeth! It was fascinating to see the layout and different sizes and shapes of each of the teeth! We then had a go at creating a 3D model of our own teeth using clay. This proved pretty tricky and required strong attention to detail, but we had lots of fun as you can see from the photos below. Having had a go at creating our models, we used mirrors to check them against our mouths for accuracy. Finally we explored the different names of our teeth, their functions and how our teeth change as we grow older. 

We then looked at how we can keep our teeth healthy, discussing the effects of different food and drink on teeth and how we can prevent tooth decay and gum disease.

We finished the lesson by planning and setting up an investigation into the effects of different drinks on teeth. We decided to model the action of various liquids on teeth by immersing eggshells in different liquids and observing the effect of those liquids on the eggshells over time.

We made sure that the size of the eggshell pieces and volume of liquid were the same in each container in order to make it a fair test. We’re looking forward to seeing the results in two days’ time!

Long Close School