We are finishing this half-term’s science project by publishing our results as posters.
The posters will be on display first thing on Tuesday morning. If you can, please come in and talk to the children about their work.
Culture of microorganisms that we took from Sarafina’s tongue!
We’ve learned that microorganisms can be helpful or harmful to human life. Today we learned about a single-celled microorganism that has been around for hundreds of millions of years and is very useful in baking. Yeast.
We did this experiment – https://sciencebob.com/blow-up-a-balloon-with-yeast/. Yeast is added to a warm sugary solution in a bottle and it starts to feed on the sugar and produce carbon dioxide. A balloon placed over the neck of the bottle inflates as the carbon dioxide is released. Here’s our bottle and balloon after about 20 minutes.
Earlier in the day, each table team had made bread dough – some with yeast and some without – and we’d left it to prove in the school boiler room. After a couple of hours, we could see that the dough with the yeast had risen and the other hadn’t. We learned that this was because the yeast, feeding on sugars in the flour, produces carbon dioxide (just as in the balloon experiment), which is then trapped in millions of bubbles in the dough, causing it to expand and leaving air pockets in the eventual baked bread. We baked our bread and ate it at the end of the day and it wasn’t bad!
We learned a little more today about the incredible world of microscopic organisms (microorganisms – bacteria, viruses, fungi, algae etc). The first forms of life on earth (dating back billions of years), found everywhere on the planet (from deep in the Earth’s crust, to the bottom of the ocean, to the outer atmosphere), incomprehensible in number (thousands of time heavier, when combined together, than all other living things combined), some essential or helpful to human life, some causing illness and disease. We’ve tried taking our own microbiological samples from different places (including Sarafina’s tongue – there are more than 7 billion microorganisms in a typical human mouth apparently!) and we’re going to see what grows in agar-filled petri dishes (pictured below) over the coming days. If we see anything then we’ll make up some slides and have a look under the microscope. Exciting!