Sweet potato sprouts

Look what I found in the back of the pantry! The white potatoes have sprouted a little, but the sweet potato has gone to town!

 

The sprouts are all kinked up because they ran into the underside of the shelf above.

 

Chubs and I (well mostly me) had lots of fun observing their growth

Red Cabbage Indicator investigation

Red cabbage indicator - full of awesomely awesome awesomeness.

Crash course in acid base chemistry for those of you playing along at home:

Acids are substances that release hydrogen ions. Bases are substances that accept hydrogen ions. No need to worry about those last two sentences if they scare you, the investigation will still be awesome. Water soluble bases are called alkalis, so in everyday situations the terms 'base' and 'alkali' are pretty much interchangeable.

pH is a measure of how acidic or basic a substance is. pH 7 is neutral - by definition pure water is exactly pH 7. The more acidic it is, the lower the pH, so anything below 7 is acidic. The more basic it is, the higher the pH , so that's the above 7s.

pH scale facts:
- The numbers in pH actually mean something - there is a reason that 7 is neutral. It's not an arbitarily assigned number like many of the other scales that we use.
- Each increment means ten times - so something at pH 5 is ten times more acidic than a substance at pH 6. A substance with a pH of 4 is one hundered times more acidic than the pH 6 substance.
- The 'p' on pH means something, and so does the 'H'. The p is always lower case even when at the beginning of a sentence, and the H is always a capital.

An indicator is a special substance which changes colour depending on what pH it is. One of the coolest and easiest indicators - especially for little investigators - is red cabbage indicator. it has very distinct colour changes, is dead easy and you don't need to worry about harmful chemicals poisoning the kidlets.

Preparing the indicator

Get a red cabbage. You don't need much - I was making heaps for a large group, but if you're just doing it for a few people then a quarter of a cabbage will be heaps. Chubs wasn't keen on the whole cabbage, she wanted the pretty half one, so I had to swap the half for the whole when she wasn't looking. Hopefully you can avoid this - for less that one hundered kids then a quarter cabbage will be heaps.

Roughly chop

Chop the cabbage roughly. You want to allow the red colour to 'leech' out.

Cover with hot water

Bung it all in a saucepan and cover. Heat it for a while (about 10 - 15 minutes, no need to be fussy)

Soggy cabbage

When the colour has started to run out of the cabbage and it looks 'washed out' then it's done.  

Strain

Strain it out into a tub or bowl.

Yuck cabbage

It feels very wasteful, but I ditch the cabbage each time. I'm sure there's a recipe to do something with it, but it does seem a bit like a Dickensian work house. If anyone has any ideas, let me know!

The investigation

One of the great things about this investigation is that you can just get in and play. It can be as structured or as relaxed as you want it to be. As long as you are using foodstuffs then it's totally fine for little hands and mouths. If using anything that might sting eyes then be careful, but I'm guessing if you're reading this then you had a toddler and you don't need me to tell you that.

The RCI will stain hands like beetroot, but it's not harmful and will wear off quickly. Clothes staining can be a bit hit and miss - but this is a good one for play clothes anyway. It can fizz a lot - so it's messy and wet, but easily cleaned. Best bet is to do it outside where you can just hose everything off.

Here's a few samples that I tried this afternoon. A bicarb solution (sodium carbonate or sodium hydrogen carbonate, depending on which brand), vinegar and water is more than enough to get you going for a while. Milk, lemon juice, toothpaste suspension, apple juice, sugar solution, dishwashing liquid and anything else you can find make great things to test.

RCI will turn to different colours depending on the pH. Most items which are toddler safe are in pH 5 - 9, so green, blue/purple and pink will be the colours you see the most.


For this investigation, I added the RCI first - these are just RCI.

RCI only

I added some bicarb solution to one, more water to the next one, and then vinegar to the last one.

 

With samples

One of the great things about indicators, is that they aren't like dyes or paints. If you mix them together, then they will keep changing to the colour that the solution is. You can keep mixing the substances together and it won't end up as one brown murky mess like paint or food colouring would. For the pHs of normal foodstuffs, RCI will change between pink, blue, purple and green.

Vinegar and RCI in the bottom glass (pink)
About to add bicarb and RCI solution from the top

In the photo above, I added the bicarb solution from the previous photo to the vinegar one.

It fizzes like bicarb and vinegar normally do
Be careful if you're not expecting this.

 

Once the carbon dioxide has fizzed off, you can see that the RCI is still pink (so acidic) but it's less pink that it was. This is to be expected; the bicarb just neutralised it a bit. If you keep adding more bicarb (either solution or powder) then it will become more purple/blue and then green.

Keep mixing, keep trying things out, keep investigating. It's lots of fun! Make a table with your results and be very organised, or just keep playing. Lots of fun - enjoy.

Visit to the Sciencentre

Woo hoo! Sciencentre trip!

 

It had been long time since I'd been to the Sciencentre. BC I used to volunteer when it was still in George Street. I'd not been over since it had moved to be part of the museum building proper at Southbank.

 

It was lots of fun, and Chubs just loved it.

 

Making whirlpools

 

It's a lovely trip for the day. We get the train in because it's convenient and Chubs loves the trip. The Sciencentre is part of the Museum, but has a separate entry fee (the rest of the Museum is free). Annual memberships are available, which are less than the costof three visits. 



Orbiting fun

 

We normally take a packed lunch which can be eaten in the dinosaur garden, and there's several cafes around too. You can leave and reenter at any time, so no need to worry about wasting the fee on a meltdown.

Musical science

It did get a bit busy later in the day, and lots of older kids and teenagers moving around was a bit overwhelming. At two years, Chubs is definitely at the very bottom of the target range and a lot was above her, but there was still plenty to keep her interested. Highly recommended!

Partial solar eclipse

There was a partial solar eclipse visible on Friday (full annular eclipse visible from Cape York.) Chubs and I made a very very simple pinhole viewer - a cardboard biscuit box cot in half with a 2mm-ish hole poked in it. I held it up so the shadow fell on a white folding chair. Here's the bit you'll have to trust me on. That teeny bit of non-shade that looks round? It was actually round, with a little bite taken out of it. That is, a partial solar eclipse. Because it was last minute it wasn't very big and the poor resolution on the tablet camera didn't show the 'bite'.

Still, it was good to see something that won't be visible in this part of the world for another forty years or so, and was a great follow on from the transit of Venus earlier in the year.

National Science Week

I just realised that this post was sitting in my drafts. Sorry, it's a bit late now but hopefully it's still funny!

As National Science Week draws to a close, I would like to share with you one of Chubs' outfits from this week.

Anyone looking for a geeky baby shirt idea, here you go:

For those of you who aren't so nerdy, the symbols of the elements iodine, americium, sulphur, oxygen, copper and tellurium spell

     I Am SO CuTe

If you're giggling by now, then you probably didn't need the explanation, and I suspect that you and I are the same type of nerd.

If you did need the explanation, then you are probably groaning and rolling your eyes now. It's ok, I'm used to it :D



I also did some volcanoes (ie, vinegar and bicarb) with my very helpful and enthusiastic scientists-in-training at playgroup and at Chubs' daycare (with the big kids.) Very simple but lots of fun and dead easy to clean up! Yay for science!

The transit of Venus

As a science teacher, I was very excited about the transit of Venus yesterday.

I've been laughing about this joke all day!

The transit of Venus occurred on 6 June and is when Venus passes between the Earth and the sun, blocking a small part of the sun out. It's similar to a new moon, except it would of course be called a 'new Venus' and it happens much more rarely - four times about every 250 years. Students and staff of the at my school excitedly viewed the transit through a solar scope organised by one of my colleagues. Several concerned teachers actually approached the large bunch of students congregating around something, thinking that they needed to to break up a fight or something! The were pleasantly suprised to discover the scientists, engineers and astronomers of tomorrow excitedly observing an event which won’t occur again in any of our lifetimes.

The transit enabled so many relevant learning opportunites. One of my classes was alsready studying Earth and space, so the transit of Venus slotted in seamlessly and allowed for a richer, more relevant experience. It helped the students to understand about solar and lunar eclipses too. The historical significance of the transit in relation to Captain Cook and the Endeavour, the physics of a solar scope, the anatomy and physiology of the eye, polarised light, and the mathematical calculations involved by using the time of the transit to calculate distances were all discussed with various classes on the day. The planets literally do not align often for relevant and rich learning experiences like this.

Actual picture of the solar scope.
The white circle is the sun and the small black dot at the top is Venus.
This was the beginning of the transit.

The end of the transit on the live stream.

To quote a colleague's status update: Just had 200 students give up their lunch break to join me in a viewing of Venus. Standing room only!! Gives me hope that we WILL have science thinkers/problem solvers into the future.

That is definately something to be excited about.


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Climate change questions and KASAD10: Harvest

As a science teacher and a responsible citizen, I believe that I have a responsibility to share reliable, accessible and factually correct information. Often I have been on the receiving end of a call or email from a friend asking me to explain something to them. Sometimes it's a news story about something science-y, often it's a medical diagnosis or concern and increasingly it's a question about climate change.

I was deeply concerned and disappointed when former Prime Minister John Howard launched Professor Ian Plimer's book How to get expelled from school: a guide to climate change for pupils, parents and punters in 2011. I was not upset because I fear debate, or because I fear change, or because I fear being wrong. I was upset because the book contains many, many innaccuracies and misleading statements.

To be honest, I do not understand why there is continual 'debate' about 1) if climate change is real and 2) if human activity is responsible. The peer reviewed scientific literature explains what is happening almost beyond a doubt. I say 'almost' because science never totally 'proves' anything. Science, but it's very nature, constantly reviews its ideas. A scientific explanation is accepted because it is supported by evidence. When someone comes up with reproducible, peer reviewed evidence to support another explanation (either a slight adjustment or a totally new idea), then science changes it's views; there are countless examples of this. The evidence for the cause of climate change and the role of human activity is extensive and well examined. The vocal 'human caused climate change deniers' (or whatever term is used) have not satisfied the burden of proof expected of any scientist. The primary place to challenge scientific ideas is in peer reviewed scientific literature, not on light entertainment news and breakfast shows.

Of course, many issues in society are not only scientific issues and emotion - for better and worse - plays a very important role in how issues are received, discussed and acted upon. However; climate change is not a discussion about marriage rights, or breastfeeding, euthanisia, abortion, religion, circumcision, welfare funding or any other highly emotional and controversial issue. There are many other issues which we are happy to accept scientific opinion on - the increased safety of seat belts, the physics of why an aeroplane won't fall out of the sky and how the internet works. I don't understand why there is such a fuss about why pollution is bad, and therefore less pollution is good.

The media also have a role to play in this confusion, but I will save my opinions on this for another day.

Professor Plimer's book included in it 101 questions to ask about climate science, and the Department of Climate Change and Energy Efficiency has given extensive, high quality, research based answers to each question which can be viewed here. I have included a selection below.

Is climate change normal?

The climate has changed - temperatures have risen and fallen  - throughout Earth’s history. Change in the climate can be driven by any force that causes the Earth to gain or lose heat, causing it to become hotter or cooler. Past changes in the climate have been caused by forces including volcanic eruptions, the changing location of continents and oceans, changing ocean currents, natural variations in the levels of greenhouse gases in the atmosphere, changes to the sun’s intensity, and variations in the Earth’s orbit around the sun.
However none of these forces can explain the climate changes we are now observing. Scientists have closely examined all the natural processes that can drive changes in the Earth’s climate and have found that none explain the current warming of our climate. 
Scientists have shown, beyond doubt, that the current warming of our climate is being driven by human activities, such as burning fossil fuels and deforestation. These activities release additional greenhouse gases into the atmosphere.

What drove climate change before humans were on Earth?
Past changes in the climate have been caused by forces including volcanic eruptions, the changing
location of continents and oceans, changes to the ocean currents, natural variations in the levels of greenhouse gases in the atmosphere, changes to the sun’s intensity, and variations in the Earth’s orbit around the sun.
Scientists have studied all of the natural processes that can affect climate and have found that none can explain the sustained rise in global temperature that is being observed today. The observed current warming trend can only be explained by taking into account the impact of human produced greenhouse gases.

If the human body and food are composed of carbon compounds and all animals breathe out carbon dioxide, how can carbon be pollution?
As previously outlined in question 34, many natural substances can be pollutants when they are in the wrong place or in the wrong quantity.
The carbon we cycle through the food we eat and the carbon we exhale is part of the natural carbon cycle. Breathing does not add extra CO2 into the atmosphere. In contrast, the burning of fossil fuels does add extra CO2 into the atmosphere and this is disrupting our climate system. This is why CO2 is considered a pollutant

For thousands of years, prophets of doom have been telling us the world was about to end. It hasn’t, otherwise we would not be here. Why is it that we should believe the modern prophets of doom who tell us that our carbon dioxide emissions will destroy the planet?
This is a misleading and irrelevant question.
Climate scientists have never claimed that the world is going to end due to climate change. Instead, scientists have outlined the impacts of increasing CO2 from human activities. These impacts include increasing air and ocean temperatures, melting of snow and ice, sea level rise and increasing acidity of the world’s oceans.
Scientists have concluded that such changes in the climate will have significant impacts on our communities, economy and environment. For example, a study considering the vulnerability of Australia’s coastal infrastructure to sea level rise found that existing residential buildings valued at a total of up to $63 billion are potentially at risk of flooding from a 1.1 m sea level rise.

Why are there 60-year cycles of warming and cooling over the last 2,000 years?

This is a misleading and incorrect question (similarly to question 10), as there is no evidence in the peer-reviewed science for a 60 year warming and cooling cycle.

Professor Plimer suggests shifts in ocean processes every 25 to 30 years could cause this 60 year cycle. While changes in ocean processes can influence global temperatures, these processes move heat within the climate system and do not add additional heat to the system. For this reason, ocean processes cannot explain the observed increase in global temperatures.

There are many more questions and answers, and I encourage you to read the entire list for yourself. Whether you have a particular interest in science, climate change or you are just a responsible global citizen who wants to be informed, then I strongly recommend this resource and the other sources available on the page.

KASAD10: Harvest

The colours in this one just 'pop' and again it's about a square which will knit up quickly and will allow you to play with colour.

Materials

- 8 ply yarn in three colours, approximately 30g of C1 and 20g C2 and C3.

- 6mm knitting needles
- yarn needle to weave in ends, scissors to cut yarn.

Skills and difficulty
Beginner knitter
- cast on
- cast off
- knit stitch
- changing colour at the end of row
- carrying unused yarn up the side

Colours
In this example
- C1 is hot pink
- C2 is pale yellow

- C3 is dark green

Procedure
1. Cast on 32 stitches in C1
2. Knit every row (work in garter stitch) for 8 rows (4 ridges).
3. Change to C2. Knit 2 rows (1 ridge). Carry unused C1 up the side.
4. Return to C1. Knit 2 rows (1 ridge). Carry unused C2 up the side.

5. Return to C2. Knit 2 rows (1 ridge).

6. Repeat step 4 and 5 three times. There should now be five stripes of C2. End C2.

7. Repeat step 4 once.

8. Change to C3. Knit 2 rows (1 ridge). Carry unused C3 up the side.

9. Repeat step 4 once.

10. Return to C3. Knit 2 rows (1 ridge).

11. Repeat step 4 and step 10 four times. There should now be five stripes of C3. End C3.

12. Return to C1. Repeat step 2.

13. Cast off and leave a 50cm tail.
14. Weave in ends and butterfly the tail.

Return to all the KASAD posts

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