In this easy elementary science project we are going to experiment with yeast. I wonder if you know what yeast is? Well, it is a type of fungus that lives on the skins of many fruits. A spoonful of yeast contains millions of little single-celled organisms (it is very simple organisms.) These organisms work like tiny factories to by taking sugar and making alcohol and carbon dioxide gas. This is the process that turns the mixture of grain and water into beer and the bubbles it produces are used to make bread light and fluffy. We are going to have a look at the conditions that are necessary for the yeast to grow.
This is one of our easy elementary science projects where adult supervision is vital as we are going to use hot water. Ask an adult to help you with the boiling of the water.
The purpose of this science project is to find the ideal conditions for yeast to grow in.
What you need for this experiment:
- A kettle
- A measuring jug
- 4 Small glass jars
- Dried yeast
- 2 Heatproof bowls
- A teaspoon
- Dried yeast granules
- Clear film
- 3 Elastic bands
- 4 Colored stickers, green, red, blue and yellow
- Ice cubes
How to do this easy elementary science project:
- Fill the kettle about half full with water.
- Boil the water to kill any organisms that might interfere with the working of the yeast.
- Now place the stickers on your glass jars.
- For safety’s sake also mark the stickers a (green), b (red), c (blue) and d (yellow).
- With a teaspoon, place a level teaspoon of yeast into each jar.
- Now you place the same amount of sugar in each jar.
- Place the jar with the yellow dot (d) away in a warm place.
- In the remaining jars, pour about 2/3 cup of the cooled, boiled water into each of the remaining bottles.
- Cut a piece of clear film for each of the remaining 3 jars that is about twice the width of the jars.
- Stretch one piece over the neck of each of the remaining jars and secure it with an elastic band.
- Place the jar with the green dot (a) in a warm place.
- Pace the jar with the blue dot (c) in one of the bowls and put some cold water and ice in this jar to keep it cold. If the ice starts to melt, add more ice to keep the water cold all the time.
- Now you place the jar with the red dot (b) in the other jar and pour some very hot water in the bowl. Ask and adult to help you with this. The water must be very hot but, not boiling as that may cause the jar to break. If the water start to cool down, add extra hot water to keep it hot all the time.
- Check on your jars regularly for the next 2 hours, keeping the conditions for each jar as it started.
- Make meticulous notes of everything that happens.
- Can you explain why it happens?
- How do you think this knowledge can be used in baking bread?
If you did this easy elementary science project correctly, the following will happen:
- The yeast in the jar that was kept in the hot water (red, b) lies in a cloudy layer at the bottom of the jar as the yeast was killed by the hot water.
- In the jar that was kept in the cold water (blue, c) there is only a little froth at the top of the jar as the cold slowed down the yeast. (I wonder if you can think how this information can be of some use to a baker.)
- In the jar that was kept in a warm place (green, a) the yeast has fed on the sugar and water and the resulting carbon dioxide should be pushing up the clear film already.
- The yeast in the last jar (yellow, d) shows no sign of any activity as the dry yeast is hibernating and will only become active in the presence of water, sugar and warmth. (Not too hot, because we have already established that overheating will cause the yeast to die.)
This easy elementary project is proofs that even doing the simplest experiments can teach us all something of value. How do you think what we learned today can be of practical use to us? In fact it has been used for years in the process of baking bread, making wine and making beer.