Yeast sugar and balloon practical
- Thread starter Archie64
- Start date
LazyChemist
Science. When Witchcraft and Guessing fail.
Gave out dried yeast and glucose and let them mix it in the boiling tube with warm water. Left in a warm water bath. Start at the beginning of the lesson to give it a lot of time. Most classes got some good results.
Like the idea!
Let them set it up in 100ml conicals and "leave in the lab" until next lesson. Before next lesson, add a dash of ethanol to each conical, chill in fridge, put balloon back on, allow to warm to room temperature in time for them to view. If the heating is on, put them on/near the heater because biological molecules work best if they're kept warm.
CovTech
Lvl 41 Alchemist
Not sure a test tube sized sample would inflate a balloon
That said....
You need to jump start the yeast
Mix up your yeast suspension about an hour prior to the lesson and pop it into a water bath at around 35oC
About half hour before the lesson sprinkle around 1-2g of glucose over the surface of the yeast suspension
By the time the lesson starts it'll be frothing like mad as the yeast respires
That said....
You need to jump start the yeast
Mix up your yeast suspension about an hour prior to the lesson and pop it into a water bath at around 35oC
About half hour before the lesson sprinkle around 1-2g of glucose over the surface of the yeast suspension
By the time the lesson starts it'll be frothing like mad as the yeast respires
it will make it stand up, it's a standard fermentation practical.
CovTech
Lvl 41 Alchemist
I know that
I've just always seen it done on a larger reaction vessel - conical flask, 500ml or bigger plastic bottle etc
Never on a test tube
where are you getting your yeast from, it's about a pound a box in waitrose.
This is key- you need to pre-stretch the balloons by blowing them up then letting them deflate.
I second this. blow them up a couple of times and deflate before giving them out.
Is it the respiring yeast practical? You've got to heat the water up to 30ºC (a kettle works for that). Stir the mixture.
Last edited:
Alex@Bunsen
bunsen.education - science supplies search engine
We used to either arrange this for the summer/early autumn or put it over the radiator/in water baths depending on what they were investigating. But it was pretty messy and temperamental.
I have been researching this and found this information. We now put two spatulas of yeast into a test tube and add 7ml of glucose solution. We get a result in the 50degrees water bath
The fermentation of sugars using yeast: A discovery experiment | Chem 13 News Magazine
Enzyme catalysis is an important topic which is often neglected in introductory chemistry courses. In this paper, we present a simple experiment involving the yeast-catalyzed fermentation of sugars.
of a double and the teacher phones at the start asking where the practical is..............