Black is black.....or is it?

We did an inveSTIGation into paper a while ago, looking closely (using a microscope as well as hand lenses) at lots of different kinds of paper; from ordinary A4 writing paper, to fragile tissue paper; from shiny greaseproof paper to stretchy crepe paper.

Another type of paper we looked at was a special 'absorbent' paper called filter paper or blotting paper. When we looked at it using the microscope, we noticed that the fibres were tangled and there were little spaces between them. Blotting paper is used for soaking up liquid (a bit like paper towels). The liquid gets trapped in the spaces between the fibres.

Just for fun (after all, if you can't do things 'just for fun' on your birthday, when can you?) we decided to use our blotting paper to take a closer look at black.

First we asked ourselves 'What is black?'
Here are some of our thoughts:

It's a colour
It's dark
It is the darkest colour
It's the opposite of white
You could mix all the dark colours to make black

Next we wondered, 'Are all blacks the same?' Is black black?
We decided that:

Some blacks can be darker than others but that really, black is just black.....

Here's what we did to learn a bit more about black.
1) We collected some different black markers



2) We cut four or five narrow strips of blotting paper
3) We drew a splodge of black from each marker near one end of each strip
4) We carefully hung the strips over the edge of a plastic beaker
5) We poured water into the beaker so that it just touched the bottom of the blotting paper but not the splodge of black
6) We waited to see what would happen.....

Almost immediately, we noticed the water creeping upwards, towards the splodges of black. Then something strange happened; as the water reached the splodges of black we started being able to see different colours that must have been hiding there.....



We compared the colours that we saw in the different markers.



We found purple, pink , brown, orange , yellow and blue hiding in our different black markers!



Remember our original question.....Black is black.....or is it? Well, is it?

Oh dear.....that had got us started.

We remembered that the primary colours are red, yellow and blue and that all other colours can be made using them; for example, purple can be made from red and blue.....and we wondered if it is the same when colour for markers is made.....
Would we see only red in a red marker? Would a purple marker have red and blue hidden inside it?

Why don't you have a go at a similar inveSTIGation and see what you discover?

What's it like? Clay

We have been getting our hands dirty; squeezing, squashing and prodding a dark earthy heavy lump of clay.



Even as we were using it, so it was changing, slowly turning from a glistening black to a drier greyish white. We found that we had to keep our hands wet to stop our clay drying out and crumbling as we worked it. It became more and more difficult to make it into the shapes that we wanted.

We want to know whether, once it has dried and gone hard (as we believe it will) it will be possible to change it back to its original glistening black or whether the change is permanent.

Feely Games get a workout.....

Such excitement on Friday.....we had a visit to our class by the BIG KIDS from Class 6 and we invited them to play our games with us. And do you know what? They agreed! What's more, they enjoyed playing.....



Afterwards, we asked them for their feedback; here are some of the compliments we received:
Joe was told that the game was, 'Awesome; we would love to play it again.'
Chris was told, 'It's a great game,' by Max's sister.
Patricia told us that they liked it and would like to come again and play it.
Giulia was told it was exciting to play.
Danah was told that it was a game that was really good for the brain and our memory and we should play it again.
A boy told Maya that the game was really fun and he liked it.
Justin was told the game was really good.

As well as compliments, we also were given some suggestions that might make our games even better:
Giulia's group was advised to change the rules so that if someone didn't get any cards the first time, they could try again.
Per was given the suggestion that their game might be improved by turning the cards face up instead of putting them face down. Per is going to try this.

When our new friends had left, we did a little reflecting:
Danah said, 'I feel very, very happy.' Sofia too felt very happy.
Maya was pleased that her game was such fun to play.
Justin felt proud as did Umar and Azri.
Joe, not to be outdone, felt very, very, very, very proud.
Per felt nervous to start with but in the end felt very happy.
Giulia is pleased because now it will go on the Blog (!)
Swati felt very proud and Vaishnavi said it was good fun.
Tanmay and Dangi felt good, Michelle very good.
Chris thought that it was a cool thing to do.

I am inclined to agree with him.

A Little Bit of Chemistry.....

Yesterday we agreed to try and find out what makes a mixture of vinegar and bicarbonate of soda 'explode' (if you are not sure what I am talking about, take a look at Per's Blog entry on 'My Paper Mache Volcano').

Fiona, our star 'finder-outer' told us.

'Vinegar and bicarbonate of soda,' she explained, 'are opposites and when they are mixed together they kind of have a fight and a gas is made which bubbles and fizzes.'

Well of course we had to try it out to see. First a dollop of bicarbonate of soda. Next a dribble of vinegar. Give it a swirl and.....wheee.....a chemical reaction!

bubbly bubbly bubbly

So far - so much fun!

Now down to the serious stuff. We found some litmus paper lurking at the back of the cupboard; this is a special paper that changes colour when things are acid or alkali or in the middle (which we call neutral).


First we dipped it into the vinegar. It turned reddish orange
Next we dipped it into the bicarbonate of soda. it turned bluey green
Finally we did the 'lick' test. Lick is 'neutral' - it turned the paper green



Vinegar is what is called an acid and bicarbonate of soda is an alkali.

Now what to do with our new-found knowledge? Tum tee tum.....

Remember all those white materials; the ones we tested to see if they dissolved or not? Well how about finding out whether they are acid or alkali or neutral?
We mixed salt, sugar, washing powder, white powder paint and chalk with water to make 5 solutions. We dipped litmus paper into each solution and recorded our results in a table.


Take a look at our results. Were you surprised by any like we were?


We had thought that sugar might be acid because we know it can make holes in teeth.
We weren't expecting washing powder to be alkali; we thought it would be neutral.
What other things could we test?

Remember that yucky-tasting salty water?

Do you remember when we dissolved salt in some water? And how Patricia (brave, brave Patricia) tested that yucky-tasting salty water? And how we were wondering where the salt had gone to?

Well, we decided to try to see if we could get the salt back out of the water again.

We poured the yucky-tasting salty water into a saucer and left it by the window, where it was nice and warm. Joe thought the water might start to disappear or 'evaporate' (which Dangi told us means turn to water vapour).

This morning, when we looked at the saucer, this is what we saw:



There was less water (which means that Dangi and Joe must have been right!) and there were also white crystals. When we looked closely at the crystals, we saw different shapes. Some were square with a cross in the middle.

We decided to keep an eye on it over the next few days to see if anything else changed.
By Friday, all the water had evaporated.



A closer look reveals many cube-shaped crystals


Azri had a go at growing some of his own salt crystals. This is what he did:
He stirred salt into water until it dissappeared (or dissolved). Then he tied a piece of string onto a pencil and dangled it into the clear salty water. He left it in a warm place - and waited to see what happened.

He brought it in to show us.

A look at dissolving

We took a look at 6 different brown-coloured materials to see whether or not they dissolved in water. We chose brown powder paint, sawdust, brown sugar, sand, instant coffee and ground coffee.

We planned a fair test. We made it fair by using the same amount of water, using the same amount of each material and by stirring each the same number of times.
We described what we noticed when we looked carefully at each beaker.

This is what Isabella noticed straightaway:



By the next day we saw that some things had changed.
Most of the brown powder paint had sunk.....



The sawdust had mostly sunk (Per said this was probably because the wood had soaked up water and got too heavy to float).....



The brown sugar had stayed the same; it had turned the water brown and disappeared completely (or dissolved) straightaway.....



The sand had stayed the same - it had sunk straightaway (Max said he knew this would happen because when you go to the beach, the sand is always at the bottom of the sea).....



The instant coffee had stayed the same; it had turned the water brown and disappeared completely (or dissolved) straightaway.....



The ground coffee had turned the water brown and the grains had sunk.....



We also took a look at different white-coloured materials to see whether or not they dissolved in water. We chose white powder paint, cornflour, sugar, salt and chalk.

We planned a fair test. We made it fair by using the same amount of water, using the same amount of each material and by stirring each the same number of times.
We described what we noticed when we looked carefully at each beaker.

This is what we noticed straightaway:

We thought the white powder paint had dissolved - it turned the water white, just like paint.



We thought the cornflour had dissolved - it turned the water white (just like paint!)
Some of the chalk had floated, but it had also made the water go cloudy.
We thought some of the sugar might have dissolved, but there were some grains on the bottom of the beaker.
Most of the salt had sunk; we saw the grains on the bottom of the beaker.

By the next day we saw that some things had changed.
Most of the white powder paint had sunk.....



Most of the cornflour had sunk.....



Most of the chalk had sunk.....



The sugar had disappeared completely (or dissolved).....



The salt had disappeared completely (or dissolved).....



We wondered where the salt had gone; it had disappeared completely (or dissolved) which meant we could not see it. So where was it?

Why not ask our brave 'guinea-pig', Patricia? She did the taste test for us.....



"Ugh," she spluttered. "Salty water!"