CSI: How to Catch a Cold

This week in Science, 6B completed a scientific investigation to solve a medical mystery. They needed to interpret relevant clues in order to correctly diagnose their patient, Allison, with a mystery illness. Watch the video of our medical work below:

Science: Microscopes and Mould

5B conducted an experiment in Science recently to determine which conditions would allow for the best mould growth on bread. To begin with,we decided on the different controls we wanted to set up for the experiment. It was decided that we would test 5 different conditions, by placing a slice of bread into 2 sandwich bags and then taped closed (to ensure no mould spores could escape):

  1. Bread
  2. Bread with some water
  3. Bread to be left in the fridge
  4. Bread to be left in the freezer
  5. Bread with salt sprinkled onto it

We began by leaving the slices of bread exposed on a table at the back of our classroom. By doing this, we encouraged mould spores in the atmosphere to land on the bread. This would help the progress of our experiment move more quickly.

Students then teamed up and were given the conditions that their slice of bread would be stored under for the next 10 days. After all the slices of bread had been double bagged and taped shut, we left them in warm areas around the room.

Here are what our bread samples looked like after 10 days:

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Bread
2
Bread + Water
3
Bread in fridge
4
Bread in freezer
5
Bread + salt

Our results indicated that while bread by itself began to produce some mould, the combination of bread and water produced high amounts of mould. Bread that was placed in the fridge or freezer did not produce any mould, as did the bread that had been treated with salt. Salt is great at inhibiting the growth of mould, but due to the amount of salt that was added to the bread, it would no longer taste very nice.

Afterwards, we examined the mould with a digital microscope, to get a closer look at our school-grown microorganisms.

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We used some simple microscopes to look at various samples on slides, such as materials, fibres, plastics, food samples, insect samples, etc. It was interesting to see what a lot of these things look like under the magnification of a microscope.

 

Science: Yeast Experiment

Within our study of microorganisms this term, we have been learning about the role of microbes in food production. Products such as cheese, yoghurt, and bread require microorganisms to help make them. Yeast is a single-celled fungi that is important in the bread-making process. Have you ever noticed the tiny air bubbles in a piece of bread? Take a closer look. Yeast is responsible for creating those air bubbles. We conducted an experiment using yeast and other ingredients, to see which combination, if any, could create enough air bubbles to inflate a balloon. If you would like to try this experiment at home, here is what you will need:

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Place the following ingredients into each of the bottles:

Bottle 1: ½ cup warm water + ½ teaspoon active dry yeast
Bottle 2: ½ cup warm water + ½ teaspoon active dry yeast + ¼ cup sugar
Bottle 3: ½ cup warm water + ¼ cup sugar
Bottle 4: ½ teaspoon active dry yeast + ¼ cup sugar

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Place the neck of a balloon over the top of each bottle. Make sure that no air can escape the bottle. Gently mix the contents of each bottle then leave in a warm area for an hour.

After an hour, we checked the progress of our experiment. We could see that the combination of warm water + yeast + sugar was starting to make the balloon inflate. We decided to leave the experiment overnight and check back the following morning. These were our results.

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So, how does this all work? Well, the warm water activates the dry yeast (kind of like being woken up by someone throwing water on you). The yeast is hungry and begins to eat the sugar (similar to how we get hungry and need to consume food). As the yeast eats the sugar, it produces carbon dioxide, forming bubbles and beginning to fill up the bottle. As the carbon dioxide reaches the top of the bottle, it goes into the balloon, causing the balloon to inflate.

Interestingly, one of our groups found that their bottle containing water and sugar had also begun to inflate the balloon. This is most likely because some wild yeast (from the general atmosphere), or leftover yeast on the funnel, found its way into the bottle and ate the sugar. This shows that you do not need to have much yeast for this to occur.

Science Jokes

 

Hey, 5B. I came across this on the interwebs and thought you guys would get a good chuckle out of this after learning about antibiotic resistance in Science last week. I guess you could say I couldn’t resist myself.

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