Easy Elementary Science Projects: Testing with Yeast

In this simple 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 skin of many fruits. A tablespoon of yeast contains millions of small single-celled organisms (they are very simple organisms). These organisms function like small factories taking in sugar and producing alcohol and carbon dioxide. This is the process that turns the mixture of grain and water into beer and the bubbles it produces are used to make a light and fluffy bread. Let’s take a look at the conditions that are necessary for yeast to grow.

This is one of our easy elementary science projects where adult supervision is vital since we are going to be using hot water. Ask an adult to help you boil the water.

The purpose of this science project is to find the ideal conditions for yeast to grow.

What you need for this experiment:

• Boiled
• a measuring jug
• Water
• 4 small glass jars
• Dry yeast
• 2 heatproof bowls
• A teaspoon
• dry yeast granules
• clear film
• 3 elastic bands
• 4 colored stickers, green, red, blue and yellow.
• Sugar
• ice cubes
• Scissors
• pen

How to make this easy elementary science project:

1. Fill the kettle halfway with water.
2. Boil the water to kill any organisms that might interfere with the yeast’s function.
3. Now place the stickers on your glass jars.
4. For safety, also mark the a (green), b (red), c (blue) and d (yellow) stickers.
5. Using a teaspoon, place a level teaspoon of yeast in each jar.
6. Now you put the same amount of sugar in each jar.
7. Place the jar with the yellow dot (d) away in a warm place.
8. In the remaining jars, place about 2/3 cup of the cooled boiled water in each of the remaining bottles.
9. Cut a piece of cling film for each of the remaining 3 jars that is about twice the width of the jars.
10. Stretch one piece over the neck of each of the remaining jars and secure with a rubber band.
11. Place the jar with the green dot (a) in a warm place.
12. Place 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.
13. Now you place the jar with the red dot (b) in the other jar and pour some very hot water into the jar. Ask an adult to help you with this. The water should be very hot but not boiling hot as this can cause the jug to break. If the water starts to get cold, add additional hot water to keep it hot all the time.
14. Check your jars regularly over the next 2 hours, keeping the conditions for each jar as you started.
15. Take meticulous notes of everything that happens.
16. Can you explain why it happens?
17. How do you think this knowledge can be used to bake bread?

If you did this simple elementary science project correctly, the following will happen:

1. 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 hot water killed the yeast.
2. In the jar that was kept in cold water (blue, c) there is only a little foam at the top of the jar as the cold slowed down the yeast. (I wonder if you can think of how this information can be of any use to a baker?)
3. 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 already be pushing up the transparent film.
4. The yeast in the last jar (yellow, d) shows no signs of activity as the dry yeast is hibernating and will only activate in the presence of water, sugar, and heat. (Not too hot, because we’ve already established that overheating will kill the yeast.)

This simple elementary project is proof that doing even the simplest experiments can teach us something valuable. 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 brewing beer.