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Micro-organisms

Bread Making Yeast Experiment.

 

We have experimented with baking bread with and without yeast and compared the results. We have realised how important yeast is in making dough rise.

Evie has summarised what we did.

 

Bread Making

 We did an experiment to see if bread would rise with or without yeast.

We put 500g of strong white flour in a mixing bowl, then added 1 ½  tsp of salt, 1 tsp of sugar, 15g of butter and 7g of yeast. In another bowl we added the same ingredients but left out the yeast.

We then mixed the ingredients in the separated bowls together adding 300ml of warm water to make a dough.

Next, we divided each ball of dough into quarters and kneaded each ball for about 10 minutes.

Finally, we put all the balls of dough back into the correct mixing bowl and covered it with a tea towel and left it in a warm place for 20 minutes.

After 20 minutes we took the tea towels off. The yeasty dough had doubled in size, but the dough without yeast had stayed the same.

We then kneaded the dough again and stretched it into 18 balls and put them on a baking tray. We then put them in the oven for 20 minutes at 230°C.

The end results were that the rolls with yeast were bigger than the rolls without yeast.

Come Outside - BREAD

Come Outside is a BBC educational children's television series that ran from 23 September 1993 to 18 March 1997 and continues to be repeated on CBeebies. Starring Lynda Baron. We liked watching the dancing mixing machine (but don't know what it actually is! Any ideas?...)

Chemical Reactions using Yeast

 

We conducted an investigation to see the effects of yeast in different solutions and mixtures. Olivia has summarised our results.

 

Our Yeast Investigation

We made different solutions and combinations of yeast, sugar and water and looked carefully at the results after 40 minutes. We made sure it was a fair test!

Container

SOLUTION / COMBINATION

RESULTS (after 40 minutes)

A

7g of yeast

No change L

B

7g of yeast, 100ml of warm water

Slushy yeast, froth

C

7g of yeast, 100ml of cold water

Slushy yeast, froth

D

7g of yeast, 10g of sugar

No change L

E

7g of yeast, 100 ml of warm water, 10g of sugar

Slushy yeast and sugar, froth, it had risen to the top of the cup! J

F

7g of yeast, 100ml of cold water, 10g of sugar

Slushy yeast and sugar, froth J

 

Class Three became Health and Safety Inspectors who had been called to a very dodgy Burger Bar run by Mr Ivor Tummybug.

They soon discovered that anyone who ate in the restaurant would indeed have a tummybug at the very least, and they were so outraged that they wrote letters to the owner to tell him of their findings and recommendations.

 

They tried to combine their persuasive writing skills with effectively chosen statistics and quotes, as well as demonstrating their scientific understanding of micro-organisms.

We turned the letter writing session into a competition, and I am pleased to announce that the top 5 letters were written by:

Thomas, Olivia, Frankie, Archie and Evie.

These winning letters, along with the letters of some runners-up appear on this page below. Also, you'll find  the appalling photos of their visit and their winning certificate. Their prize is NOT an all-expenses paid trip to the Burger Bonanza Bar, don't worry! Don't look at the photographs if you're about to have your dinner!

Rotting Hamburger Timelapse Footage

The Sneeze How Germs are Spread

Ever wondered why you should wash your hands when you've sneezed? This video explains why it is so important.

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