Today, to consolidate what we have been learning in Science lessons, we made bread. We used a breadmaker and made 2 loaves of bread. They were identical except that the first loaf contained yeast and the second one did not. We wanted to see, at first hand, the effect that yeast has on bread. We have learned that yeast is a micro-organism that feeds on sugar and there is a chemical reaction that creates a gas called carbon dioxide. The gas is what creates bubbles in the dough and makes the dough rise. Our first loaf was taller, lighter and tastier than the second which was about half the height, quite doughy and chewy. The photos will help you see the difference. Have you ever made bread?
Year 5 are studying micro-organisms in Science lessons. We have been investigating yeast, a tiny living thing that can do amazing things. We have conducted some experiments. Firstly we wanted to know what yeast needs to ‘work’ best. We set up an experiment with 4 bottles. Bottle 1 had yeast and warm water, Bottle 2 had yeast, sugar and warm water, Bottle 3 had sugar and water and Bottle 4 has sugar and yeast. We made predictions about what would happen and also observed what was happening during the experiment. After 1 hour this photo shows what had happened.It is clear that in Bottle 2 the balloon inflated faster and bigger than the rest. After discussing our findings (and some more research) we discovered that sugar is food for the yeast and the water activates the yeast. The reaction between the yeast, sugar and warm water creates the gas called carbon dioxide which causes the balloon to inflate.
Today we continued our investigation to see which temperature the yeast likes best. Again, we placed yeast and sugar in bottles. We added cold water to bottle 1 (white balloon), warm water to bottle 2 (green balloon) and boiling water to bottle 3 (red balloon). We made predictions and recorded our observations. This is what the bottles looked like after 45 minutes. What do you think has happened in each bottle?
What temperature do you think yeast likes the best?
We also know that yeast is a very important ingredient in bread. We are going to make some bread soon.
Can you explain why yeast is important in breadmaking? Do our Science experiments help you to understand?
At the start of our Science unit on Electricity I conducted a poll to see how my students felt about Science.The results were very encouraging. As we have explored electrical circuits, torches and light bulbs there has been a high level of interest. In the words of a famous Australian scientist “Why is this so?”
Science, in a primary school classroom, is hands on and fun. Even without knowing it the students are learning important skills and values. Last week after reading the story of Italian scientists, Alessandro Volta and Luigi Galvani, I asked the students to identify key characteristics these two scientists displayed. Then we generated a list of words to describe scientists. What did we find? We found a list of words that could describe many of my students. Words like resilient, persistent, determined and courageous came up again and again. So are my students scientists? Of course they are! They are learning the value of questioning, reasoning, predicting and explaining. They are learning how to approach problems and how to react if results don’t reach their expectations. They are learning to be thorough and consistent and fair.
Scientific thinking seems to be a good model for how to approach life in Year 5. Perhaps that’s why my students love Science. They are learning values and attitudes that will stay with them and serve them well in all aspects of life.
What do you think? What do you enjoy about Science lessons at your school?
In class today we made two loaves of bread. We made them in a breadmaker and followed a recipe. Both loaves were exactly the same except the second loaf had no yeast. We have been learning all about yeast and know that yeast feeds on sugar and produces carbon dioxide. We have done experiments in bottles but wanted to see the effect that yeast has on dough. These photos show the difference.
The loaf with yeast rose to about 13cm and it was light and airy and tasted delicious! The second loaf was heavy, it rose to only 5cm and looked and tasted more like dough. Even though it didn’t taste much like bread we all gobbled it up anyway!