The final eggs-periment

All good things must come to an end, and so the egg experiment must conclude. In between the last post and this one, we took the dark purple egg and place it in plain, colourless water to see if the colour would leach back out again. Interestingly, the blue did but the red didn’t, so the egg went a little more red-purple afterwards. However, sitting in the same thing of water for a few days also encouraged a bit of mould – bringing about this last test. 

We had to know – what would happen if we boiled it? Would it explode or stay intact? Would it remain purple or lose all of its colour?

Some observations in the end:

1. The egg did stay intact but it was very soft, even though we boiled it for almost 20 minutes all up. It almost fell apart in my hands after cutting it!
2. It did stay purple but lost a large amount of its red colour in particular (as you can see by the water in the jug above, which was the water we boiled it in).
3. The purple colour penetrated into the yolk, but not all the way. Some of it is still clearly yellow, even after several days of soaking.

I showed this off to my Year 10 class this morning – confirming their view of me as a science geek! Who else would do this at home for no real reason other than curiosity?

 

Eggs-perimentation continued (again!)

Just can’t let this thing go – I’m sure my daughter lost interest a long time ago, but still we soldier on for curiosity’s sake.

So now we took the egg out of the blue water and placed it in red water to see what might happen to the colours – and sure enough, it went purple!

Eggs-perimentation

Following on from yesterday’s post, my wife and I were just too intrigued to leave it there. We had to know – how porous is that membrane? Can other substances besides water make their way inside the egg?

So we tried with blue food colouring:

 

 

 

 

 

 

 

 

 

Win!

Some days are harder than others…

Today was a hard day. I’m not proud of it, but I’m not too ashamed to admit it either. Sometimes you go out on a limb to try and do something engaging with and for students and it falls flat in a big way.

Today was one of those days.

I had hoped that my students would be ready to embrace PBL and claim some independence – to follow something that interests them and engages them. But instead the opportunity and excitement dwindles unused. I really really want PBL to work in my classroom, but so far it has come off half-baked and I can’t help but be skeptical that they have really learned anything. Maybe I’m being too ambitious, or maybe I just can’t see the forest for the trees. I know in my mind that it’ll take time for them to get used to this style of learning, and it’ll take time for me to be able to let go. But right now, in my heart, I can’t help but feel like it’s tanking.

Hopefully tomorrow will be better!

Chemistry meets Cuisine: The Science of Eggs Pt 2

Just a quick post to update you on a little science experiment we’ve been running at home, based on an activity I was doing with my Year 10 class this week.  At school we’ve been studying different chemical reactions and one that I had heard about (but not actually tried) was the reaction between the shell of an egg and vinegar. So of course we had to try it!

When the egg is immersed in vinegar, the acetic acid in vinegar reacts with and dissolves the calcium carbonate in the egg shell. This eats away the hard shell, leaving just the stretchy membrane underneath. The result is like an eerie water balloon – and which pops just as easily, as my students found out the hard way!

Here’s a photo of our results – before and after.

The ‘after’ is noticeably bigger because the eggshell is porous and allows the vinegar to move inside the egg. Cool huh!?

PBL Wrap-Up

Well my Year 9 class is almost at the end of their mini-PBL topic on earthquakes, and I feel like we’ve all learnt a massive amount. Tomorrow I look forward to seeing their final videos and showing their work to the whole class – I hope it’s very satisfying for them!

Inspired by reading Bianca’a post, I’ve definitely learned so much about how to implement PBL in the classroom – although, to be frank, it’s probably more what NOT to do. But that’s the way with anything new, as the first time is going to be a bit rough around the edges. I’m just proud that I gave it a go. Some of my take-home lessons:

• Students need structure and boundaries in which to be free to experiment. This includes clear expectations and guidelines about what to do and how to go about it. Too much freedom is dangerous for the first time at PBL, because it saps their initiative. The problem is working how much freedom is too much!
• Students need to buy into the task – if they couldn’t care less about what they’re doing, then why would they give it their best? I think this was alright with our unit but it wasn’t enough motivation for some of the groups.
• Planning, planning and more planning. This is something I could have done far better, as a lot of it felt haphazard at times. I must admit that the decision to use PBL for this part of our unit was made quickly and without a whole lot of preparation, which I will have to work on!
• Groups need to be chosen or formed carefully. Some groups are all leaders, whereas others are all followers. Neither works effectively, but how do you choose or let the students choose in order for it to work best? No clear answers on this one. We also had a number of setbacks with student being away and their group being (or at least feeling) unable to carry on with them away, because they had the equipment/files/whatever. This should be a bit more straightforward to address, as hopefully we can use the cloud to store their files so they can all access them from wherever.
• The students need regular deadlines and feedback points, which would help me to better keep track of where everyone is up to. It also gives them reminders to stay on task and keep the pace. I had one group who has done almost no work, while making it look like they were working. As you can appreciate, this is beyond frustrating but how can you motivate these students? Again, still no clear answers on this one.

Still looking to learn more and I can’t wait to implement the next one!

Alone in the night

Here’s a little something that I came across this evening – a time-lapse video of the Earth at night from the International Space Station (ISS). Enjoy!