Lesson Plans Provided by Steam'n | Print

My Yogurt is Alive

A fun activity that includes making yogurt from live bacteria cultures!

The students will observe the growth of yogurt and describe the process as the live cultures grow.

1) 2qts Milk

2) ½ cup Yogurt (We used an organic, non-flavored yogurt)

3) A microwave safe mixing bowl

4) Mixing Spoon

5) Thermometer

Make your own yogurt: There are many different recipes to make yogurt, however this is the one we used.

Allow the store bought yogurt to reach room temperature.

Heat milk in a microwave safe bowl, you ideally want to get it to be 180 degrees. Check carefully with a thermometer. Once the desired temperature is reached, add in the yogurt and stir the mixture together. By adding the yogurt or, the live cultures into the milk, you are allowing the cultures to thrive and grow as they will feed off the natural sugars in the milk. During this step sugar can be used to sweeten the yogurt.

Tip- A natural way to sweeten your yogurt is to add honey, which you can use instead of sugar.

Cover the bowl with saran wrap to keep dust particles out. Allow yogurt to sit at room temperature for about 4-6 hours. Observe the changes; the mixture is starting to thicken as the live cultures grow. Place the bowl in the refrigerator for another 4 hours until the yogurt is ready to eat!

You can begin this discussion by asking students if any of them packed a lunch and asking the various things they may have packed. Point out yogurt, as it is a popular snack among younger students as it has been marketed in fun pouches and in an array of colors and flavors. Share with students why yogurt is a nutritious snack. Did they also know that yogurt is alive with many live bacteria cultures? Prove to them that you can make your own yogurt by growing some of the live cultures already found in yogurt.

Sample the yogurt with your students, adding fresh fruit adds a delicious flavor. Have students write and/or draw in a journal the process they observed of the growth of the yogurt. Discuss with students that not all bacteria is bad. There are bacteria that are good for us and present in our bodies, eating yogurt can help improve our immune system. There are also the harmful bacteria that can make us sick, which is why it is important to wash your hands.

*Since Bacteria is an example of a unicellular organism this lesson can be modifed for older students using: PA Standard 3.1.6.A6. Identify examples of unicellular and multicellular organisms.