Monthly Archives: December 2012


Click below for link back to Mrs. Yollis and her class's original post...

Science Stop: A Colorful Science Lesson

Dear Mrs. Yollis and class,

Science is one of my favourite subjects. Okay, you probably know just about any school subject is a favourite of mine. It comes from being interested in so many things but science (zoology) was my study at university before I trained as a primary (elementary) teacher.

Light is fascinating. Light is a form of energy. Our very bodies have energy down to the atoms making us up. It’s the way our senses interact with the energy that allows us to see, feel, touch, taste and hear.

At first I was wondering if the students might try to trick you by using chemicals to make unexpected colour changes. Here’s a You Tube link to show how this might be done.

I can see they were very careful about their demonstrations so you were able to predict what colours would result.

Below is a colour diagram I created for you. There are three primary colours in light (red, blue and yellow). Mix equally any two primary colours and you will get a secondary colour (purple, orange and green).  Mixing different amounts of primary or secondary colours can make all of the colours we see. Black is the absence of light whereas white light has all three primaries (which is why a prism can refract white light to show colours and we see rainbows when water droplets refract sunlight).

Schools and students have permission to use this graphic for non-commercial, educational purposes.

We use our eyes to see but do we all see the same? I suspect, being individuals with our own eyes, we don’t see colours in exactly the same way as others. I think there are slight differences but we learn what we see is red or blue, etc. If you could see through someone else’s eyes, the world might look a little different. What do you think?

I heard you all say light travels in a straight line. I don’t say light travels in a straight line. I say something a little different if asked…

Light travels in as straight a line as space allows.

The idea comes from Albert Einstein and his general theory of relativity (big words to explain how things work).

Have you heard of gravity? If we jump up, we are pulled back down by gravity. If you could jump high enough, the Earth’s gravity wouldn’t be able to pull you down but it would have to be a massive jump. Einstein’s theory tells us space is warped (bent out of shape) by gravity. While light travels in straight lines, the “lines” in space are bent.

Does that sound weird? I know it can be hard to get our minds around so I used a striped shirt and a round rock (geode) from my rock collection. Look at the picture below.

Schools and students have permission to use this graphic for non-commercial, educational purposes.

Can you see how the stripes on the shirt are pulled inwards and the shirt has bent down under the weight of the rock? If light was the stripes, it would travel in a straight line but space is warped (“bent”). We know this is true because, in a total solar eclipse (where the moon blocks the sun), we can see stars slightly behind the sun. The sun’s gravity has “bent” space so light appears bent.

I know the idea is hard to understand but it’s one of those fascinating things about our world. I’m not an expert in science but have fun thinking about it. I always hope I get my facts correct. 🙂

Have a great winter break. I look forward to your shared learning adventures in 2013.


Teacher (retired), N.S.W., Australia


For Battalion Hawk Bloggers (aka Global Grade 3) and their post

Let There be FOOD for EVERYONE!

Hello Battalion Hawk Bloggers,

It seems your posts always start me thinking in all sorts of directions. Your “Let There be FOOD for EVERYONE!” post is no exception. Let’s see what came to mind this time…

“If the World Were a Village” is a remarkable idea within a book. When we talk about the people of the world, it can be hard to understand what millions or billions of people are. The numbers are hard to imagine yet David J. Smith has been able to show us the meaning of the numbers by comparing the entire world to a village of 100 people, a number many of us can understand as it is often less than the number of students in our school.

 After watching the You Tube presentation of the book linked in your post, I thought about something I shared in another extended comment some time back and how it relates to my feelings on listening to “If the World Were a Village”.

In a post entitled “Genealogy – We are all one big family – for a question about the past” I looked at a little of my family history. What was interesting was realising after only 20 generations back in time (just including parents, grandparents, great grandparents up to 17x great grandparents), we have over a million relatives. I traced back about 68 generations in one line of my family and found the number to be greater than…


That number is impossible unless back through time relatives partnered relatives. I concluded, in order for us to be possible, we don’t have family trees, we have family forests. This means we’re all cousins somewhere along the way through time. Humans are all part of one family.

Thinking of this and “If the World Were a Village”, I decided to look up the definition of “village” in a dictionary. Here is the meaning I found in Australia’s Macquarie Dictionary…

Village: a small assemblage of houses in a country district, larger than a hamlet and smaller than a town. (There were other meanings given.)

Under this definition, humans may be in one big family but they don’t live in a village… or do they?

I created a short video slideshow with some thoughts on Earth as a village, humans as a family, and helping others in need.

Schools and students have permission to use this video clip for non-commercial purposes.

It seems to me Earth, being only a tiniest speck in the universe and inhabited by a family known as humans, is a small village on a universal stage. Wouldn’t helping friends and neighbours be something many of us would try to do if we could?

At this point I stopped my mind wandering because I wanted to read all of your comments on your "Let There be FOOD for EVERYONE!” post. Here are my thoughts on what you have written…

Chris – Your thoughts are very helpful. There are a number of organisations helping people around the world when they’re in need. They also help in our own countries when disasters strike. Possibly one day you may be helping one of these groups.

Jayden & Lauren – For people in countries like ours, food and clean water only means a trip to the supermarket. In many poorer countries, food isn’t easily available. In order for those with little to be fed, it seems the richer countries need to be willing to give up some of their food to help others. Perhaps instead of having a bottle of soda (soft drink for us Aussies), we could give the money to a charity and drink water.

Ben – One of the problems we can have is resources and how we use them. We might give some cows and chickens to a community. They could then eat them but if they instead looked after them, they could have milk and eggs each day. We could send them grain so they could have a meal or we could help them plant some of the grain so each year they have food.

Tommy – I see, like me, you like to look at numbers and consider what they mean. We may not know anyone who is starving but may have seen reports on people somewhere suffering hunger because of wars or droughts or famine. Using the numbers, it would mean one in four people are starving.

Think of an experiment: Every fourth person in your class becomes the starving one quarter. They are allowed perhaps a piece of bread or maybe a small vegetable to eat only once a day over the next week while everyone else has their normal food. Would you be able to sit eating your normal meal as they watched on? It’s easier for us to ignore what we don’t see. Perhaps if we “open” our eyes and see the starving as people as part of the human family, we wouldn’t sit by doing nothing.

Ella – Sharing is a skill we all are taught when we’re young. We share toys. We share sweets. We share laughs and we share tears. We do this because we are together. As our world seems to “shrink” because it is now so easy to meet through the internet, we are together with more people. As we get to better know the world, won’t we all learn to better share? Imagine the call goes out over the internet. A simple click of a button and we donate just $1. Now if just one in four Canadians clicked the button, that would be over $8 million and if one in four Australians clicked, that would be over another $5 million. Just our two countries could, by a simple click, donate over $13 million to help others in need.

Zubayda & Cemre – I have read there is about four times the number of chickens in the world as there are people. If just one in four were to lay an egg each day, that would be one egg for every person in the world every day.

Christopher & Dimitri – We share food with our friends. We share food with our family. As I wrote earlier in this post, we are one big family of humans. We only need to think globally and share with our family.

Danny & Tyler – One of the important parts of our modern world is how easy it is to move things from country to country. Giving chickens to people may not always be possible because of where they live but sharing what the chickens produce is. Eggs can come in powdered form so they won’t spoil or they can be used in making other foods. It’s sad that while many are willing to share there are others who aren’t. In some cases, the selfish stop food reaching people in need. We need ways to make certain only those who need the food can access it safely.

Chelsea & Rayann – In our history, there have been food planes. Back in 1948 t0 1949, the then Soviet Union stopped supplies reaching West Berlin in Germany. They wanted to force all of Berlin to come under their control. The US Air Force set about delivering supplies by plane. During the blockade, they made over 200,000 flights delivering up to 4700 tons of supplies daily. It saved the people from starvation until the blockade was lifted. If people could do it back then when there was a need, with our modern aircraft, imagine what could be done now.


Elijah & Amro – If we look at a small village, it would be much harder to ignore some who are going hungry but, in the video clip I added to this post, I suggested our world is like a small village if you consider just how huge the universe is. Can we continue to ignore those in need?

James – Your class’s experiment with numbers made “If the World Were a Village” a much more personal experience. It helped you place yourselves into a more personal encounter with hunger. Here are some more numbers. If there are about 7 billion people in the world and 25 members of your class, each one of you represented about 280 million people. That’s an amazing number.

AJ – As with James, each of you represented 280 million people. Your amazing experiment with numbers made it easier to understand and shows us it is possible to feed the world if only we are willing to try.

Nick & Christopher – “It is not fair that there is enough food to go around for everyone but still some people are starving.” Well said! It isn’t fair yet there are many who don’t care so long as they have plenty. By learning how we can help others, we can also learn how to care. There is something called empathy (entering into the spirit or feeling of another). If we wonder if we should help others, we should try to think of ourselves in their place. Would we like others to help us if we were in need?

Joyce – I think Ben’s suggestion was interesting. If we were to better share the available food, how would we decide? If we rolled the dice, some would get more or better food and others less. Maybe in the future the learning you do now will help you become one of the people in our world who works to feed those in need. Wouldn’t that be a challenge?

Rebecca – I do think of the world as a village occupied by one family, humans. It’s a world where there can be enough for all, where we can protect our environment for the future, and where we all grow concerned when we see need and are determined to help. The future is yours. How many of you will take up the challenge of the future and make our world a better, safer, healthier place to live?

Battalion Hawk Bloggers

At the end of your post, you state, “We KNOW it isn’t as easy as this to make sure that EVERYONE in the world has enough to eat…”

You go on to list the reasons why there are difficulties, a very important part of determining a solution to a problem. If we better understand “why not” it becomes easier to work out “how we can”.

“How can we ALL work together to ensure that the people in our global village have enough to eat?”

You have already started that journey. You know there is a problem and there can be enough. The more people becoming aware, the more there are to work towards a solution. At no time before in the history of our world has it been so easy to know where there are problems in the world and have the means to do something about it. It only takes the will to try.

One world, one village, one family… Together, hand in hand, we can achieve great things.

Schools and students have permission to use this graphic for non-commercial, educational purposes.