Science: Simple Circuits

Today in Science, we put our knowledge of electricity to the test and built simple circuits. It was a very energising (see what I did there?) lesson! Each group started out with their own simple circuit kit (or as I like to call it, a ‘cir-kit‘ ha!), including 3 insulated wires with alligator clips, a 1.5V size D battery (with battery holder), a switch, and a 1.5V bulb (with bulb holder). From here we constructed our components into circuits and switched them on (literally!). It was a real light bulb moment for most groups (sorry, not sorry), however, darker forces were at work with one group. There was an imposter (dun dun duuuuuun) in their cir-kit and they had to troubleshoot in order to figure out which component was the culprit. After switching the wires, bulb, and battery, the boys narrowed it down to the bulb holder. Lucky, as they were about to blow a fuse! As soon as we replaced it with a different one, the circuit was complete!

Then we replaced the bulb in our circuits with a motor and attached a small piece of paper to act as a type of propeller. When we turned the switch on, the propeller span. Next, we traded in our bulbs and 1.5V batteries for LED bulbs and a 9V battery. This was a little trickier as we had to ensure that the black wire of the LED was connected to the negative terminal of the battery and that the red wire was connected to the positive terminal. Then we had fun with connecting a buzzer to the circuit (producing a really annoying sound). One group worked out that the 9V battery had enough voltage to power an LED bulb and the buzzer in the same circuit. I dubbed this group the Bright Sparks.

I think it’s safe to say this was an illuminating activity! I hope you get a buzz out of our photos (metaphorically speaking, of course).

Jessamy’s Electromagnet Experiment

This term, we are learning all about Electricity & Light in Science. Last week, I set a challenge for 6B to make their own electromagnet and then test the strength by seeing how many paper clips it could hold. Jessamy went home and made her own electromagnet and brought it into school to show everyone and test out. It could hold an impressive 15 paper clips. Go, girl!

If you would like to make your own electromagnet, here is what you’ll need:

  • a large iron nail (or a screwdriver if you want something longer)
  • about 1 metre (or as close as you can get) of thinly coated copper wire (hit up Bunnings)
  • a fresh D size battery (if it’s an old battery your electromagnet will not work as well)
  • some paper clips (or small magnetic objects)

Steps:

  1. Leave some wire loose at one end of your nail (around 20cm) and wrap most of the rest of your wire around the nail. Try to coil the wire closely, without overlapping.
  2. Leave around 20cm of wire at the other end of your nail.
  3. Carefully remove a couple of centimetres of the wire coating from the ends of your wire.
  4. Attach one end of your wire to the positive terminal of the battery and the other end to the negative terminal (you can use a little bit of tape to help you, just be mindful that the battery will warm up).
  5. You have now made an electromagnet! Test the strength of your electromagnet by placing the pointy end of the nail near some paper clips and see how many it picks up.

Remember: making an electromagnet will use up your battery quickly, so make sure to disconnect the wire from the battery when you’re not using it.

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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
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Bread + Water
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Bread in fridge
4
Bread in freezer
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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.