Year 11 Microbes Internal

Today I had my Y11 for an internal intensive (rather than a mid-year exam). We've been learning about bacteria and fungi for two weeks now using a mixture of Education Perfect, literacy activities designed by our literacy specialist Marc Milford and class activities. 

Today was a bread and yoghurt-making practical that they will have to discuss for their 4-credit write-up next week. 

Hopoate and Hala sieving their flour as they begin to make bread.

Each group started off the lesson by making a slightly different type of bread using a variation of a basic recipe. After all the steps were followed and the dough was left to rise (aka the yeast were left alone with the flour to conduct anaerobic respiration) we baked the bread for 25 minutes.

Then we made observations of the appearance of the bread, and also did a taste-test. 

Chelsea with the different variations of bread (her wholemeal bread is second from the right).

After we had made bread using yeast we interacted with a different microorganism - bacteria! 

Students first heated milk to destroy any pathogenic (harmful) bacteria, and then cooled it to the optimum temperature for our helpful species. Then the bacteria were added and left to do their work for the next five hours. We'll eat the yoghurt tomorrow!

Makaydyn making yoghurt - the live bacteria cultures are in the yellow packet Desiree is holding on the left of the picture, and are about to added now the milk has dropped to the optimum 40 degrees celsius. 

The students were great and the lesson went really well. I would definitely do this with a class again - perhaps earlier in the topic, so when we discuss respiration in greater depth they would have something tangible to hook the abstract concept on.

We couldn't have run this lesson without Ms Heka helping us out in her kitchen! Hopefully we left it as we found it Ms Heka! Thanks for hosting us :) 

1104 Learns about Density

We've started a new topic for 4 credits at the end of Term 3! And depending on how hard we work, we could even do ANOTHER 4 credits in Term 4! On Thursday we started looking at different types of metals, making observations, and we weighed 1 cm cubed samples of them. 

Then yesterday we graphed their density (g/cm3) before learning what density actually is - the amount of particles packed into a given area. Objects or liquids that are more dense have more particles packed into the same volume.

First we watched this video.

Next I revealed to students the list of the liquids available to them and gave them each a piece of paper with two blank test-tubes drawn on it. Students got to draft a density tower that they thought would be most accurate, and then have a second guess by drawing a second test tube with some of the orders of liquids changed around.

The liquids we used were:

water (pink food colouring)

dishwashing liquid (green)

olive oil (yellow)

conditioner (white)

water + corn starch (bright red, lots of food colouring)

golden syrup (golden)

shampoo (white)

soy sauce (brown)

sunscreen (white)

baby shampoo (yellow)

I quite liked this activity because there was a lot of discovery learning happening. I didn't know the exact order in advance, and there were a lot of questions being thrown around like "is soy sauce going to sink through water?" which I got to answer with "I don't know, go and get a test tube and find out  before you add it to your density tower." There was also some logical thinking happening, like when Duui decided that dishwashing liquid would be more dense than water because when he uses it at home it moves to the bottom of the sink, and Brandon had a think about oil spills and water. 

I discovered that soy sauce is more dense than dishwashing liquid, because it sank right through the dishwashing liquid in my tower and sat on top of the conditioner layer. 

Most students guessed that the golden syrup would be the most dense. 

Here are some photos from our class:

Mac, David and Duui gently adding the next layer to their beakers. 

Mac's first attempt

Students working and cleaning out their beakers after failed attempts. It was quite good to get it wrong and have a layer sink through, because then they knew to add it earlier as it was more dense.

My attempt.

Mac's best "scientist face" as he studies his density tower - many more layers this time!

I think that this lesson (messy, loud, and a little silly) was a good one to illustrate density. 

Next week we'll have to start thinking about why cars and planes might be best made from more or less dense metals.. hmm...  

Year 9 Sheep Heart Dissections

My year 9 classes finally got the chance to dissect pig and sheep hearts. 

9KEm and 9TMn got to do it as part of the new 'Me, Myself and My Environment' unit, and even though we have run out of time to finish that unit we didn't want 9PLa, 9PTt or 9RTd missing out on this fun and practical learning experience!

We had a look at the aorta, as well as the left and right atria, ventricles and chordae tendineae.

Students were really good at remembering which side of the heart is bigger and has thicker walls of muscle, and explaining WHY!  (The left side is bigger and more muscular because it pumps blood around the whole body, while the right side only pumps blood out to the lungs and back).

Here is the video of their dissections - listen carefully as James' from 9RTd gives an explanation halfway through:

Year 11 Reactions of Metals with Oxygen

Today (last period Friday) the Year 11 Science class did a practical; they combusted different metals in oxygen! Some of them enjoyed showing my laptop what they were doing - I think we have some future TV presenters in class.

Here's the video of what they did:

No Year 11's (or teachers) were harmed in the making of this production! 

9PTt "Polluted Water" Puzzle

9PTt has been learning about separating mixtures and solutions using decanting, filtering and evaporating. There's only so much you can learn from listening to a teacher, so I decided to challenge them practically. 

I set up large beakers containing rocks, sand, salty water with blue food colouring and topped off the "polluted sample" with a layer of baby oil. Students had to work out how to separate the different parts of the sample to find out how much salt was in the water. 

Students decanted the salty liquid out of the beaker, leaving behind a heavy layer of rocks and sand. There was still some sand floating in the liquid, so students had to filter the liquid through a funnel and filter paper. 

Next students poured the salty liquid into a funnel while holding it closed with their thumb. They (mostly) waited patiently until all the oil rose to the top then let the water out from underneath, leaving the oil behind. 

I didn't quite trust that all the oil had been removed from the sample and didn't really feel like setting anything on fire today, so I collected back their samples and distributed a new one with only salt and water in it!

G opening the bunsen burner hole to get a blue flame

Students then evaporated off the water using an evaporating dish heated over a bunsen burner to find out how much salt was in the solution. There was a lot of engagement during this practical, and I feel that students benefitted a lot from being able to do the separation themselves.  

  Tomorrow the students are going to learn how to separate mixtures using chromatography and make some cool chromatography flowers while they're at it!