Investigating Viscosity

Today we did another investigation about the viscosity of different liquids. 

Last time we dropped a marble into the liquids, but we found that timing accurately was really difficult because the marble fell through some of the liquids very quickly.

We talked about how we could change the investigation, perhaps gaining more accurate results.  One of our ideas was to use a lighter object as we thought that it would travel through the liquid more slowly.

So, we have tested our prediction using a dice instead of a marble.

Here are some photos

We took turns pouring liquids, dropping the dice, timing the fall and taking photographs.

Here are some videos of us doing our Science work:

Here is a table of 4Bs results.  You can see the difference in the timings between dropping the marble and the dice.

We calculated that the dice fell about 3 times slower in thicker liquids like shower gel and washing up liquid but took about twice the time to fall through thinner liquids like oil, lemonade and orange!  We are still discussing the milk result... Why is it 3 times (it is thin like water)?  Did we test this accurately enough?

Whatever our decision about the milk, in Year 4 we have concluded that lighter objects fall slower than heavier objects through all liquids.

(We didn't test the ketchup because the marble is still sitting on top of the liquid after the first investigation - so we knew a lighter one would not be any different!)

Marble racing to determine a liquid's viscosity

To determine the viscosity of various liquids: milk, lemonade, orange juice, vegetable oil, washing up liquid, shower gel and tomato ketchup we measured the time it took for a marble to reach the bottom of a filled cylinder.

 

To everyone’s surprise, when dropped into the ketchup, the marble simply sat on the surface! We have decided to leave this over the long weekend so see if there is any change on Monday....................

Liquids

We've started considering solids and liquids in our science lessons:




There are these new words we don't need to remember:

• viscous = thick
• viscosity = thickness

Here's a really thick liquid that's taken 69 years to drip down:

Lentils of Spring

This is the thing I do to celebrate Spring.
Its some thing that Arabic people do, you can do it yourself if you have these things:

• lentils
• soup plate
• water

First put the lentils into the soup plate without fill in it.
Next put some water until the plate is covered (make sure the water is blended with the lentils so that it looks like the lentils are filling the plate).
Now wait to see that the lentils grow as much as 16 cm high in just 9 or 8 days!

This is what the lentils look like at my house.
They are magnificent I wish I could keep them but since I am moving house I cannot.

  

The Eclipse

Today there was a partial eclipse. At first we watched it on a live feed from the Pic de Midi in the Pyrenees.

It looked like it was going to be too cloudy to see anything here at IST. Then, just after 11, there was a small break in the clouds. We had a look at the images made by a colander.

 

Do you see? There are lots of crescent shapes!

We were happy that we'd seen it!

In 4G we videoed each other (the sound was a bit quiet) talking about the diagrams of the eclipse that we'd made:

Forming Salt Stalactites

At the weekend a month ago I made an experiment to make salt stalactites.
Here is the experiment if you want to make it.
I put water with lots of salt in two plastic glass.
I took a 30cm wool string. I put 1 end into each glass of plastic so that the end of the string touched the water.

You need to wait several day for the salty water to make the stalactites and if you are lucky
like me you also have crystals!
Some crystals were formed 2 or 3 days ago, we were amazed how they were made out of
salt.

Our evolving creatures

We started off with one simple animal:

Then a few of us made some changes, to create new animals:

Then more of us made more changes:

Then all of us started to change these. Soon there were lots of different animals:

But they were all related. They had all evolved from the first creature.

 So we started to sort them out:

It was hard!

Here's one of our trees (more to come).

My visit to the Museum of Human Evolution

During the holidays I visited the Museum of Human Evolution. It explains human evolution really clearly.

Look!

The museum was huge! We took a long time to look at everything. Did you know that men used to live in caves? We know that because they left bones and painted walls.

Another reason we know there were people living in the caves, it's thanks to the layers of rock its the same for volcanoes.

This man is not a monkey its a Habilis man .He was clever enough to use tools.

And this is not a gorilla; it's a Neanderthal man. As you see he was clever enough to make clothes of his own.

Merry Christmas and happy new year everyone!