How dense are 6S?

6S have been learning  how to calculate the density of regular and irregular objects in science lessons recently.

For irregular objects you need a measuring cylinder 

the smallest one the object will fit in is the most accurate 

Half fill the cylinder with water 

make sure you have found the mass first and written it down 

slide the rock into the water and the level rises 

We used rubber bungs too 

and did many calculations to find, first the volume 

 and then the density

 its a lot like maths

except it has real purpose!

8S are forensic

8S teams of scientists were told that the forensic labs at Gatwick were shut this morning and that they were required to analyse a white powder that had been found in a passenger's luggage.

They got straight down to testing

Observing carefully 

Heating and testing the gasses given off 

 

Making sure they worked safely 

 Testing solubility

Until they found out that it was..... 

zinc carbonate 

Did you know:

Zinc carbonate (ZnCO3), normally referred to as smithsonite, is an ore that contains the metal zinc. It was named after the English scientist James Smithson (who dedicated his fortune to create the Smithsonian museum in Washington, D.C.). The mineral has a number of uses in health care, metallurgy, electronics, and construction.  (Thanks to the eHow website)

Have 7C got guts?

The last experiment of this topics for 7C is to make a model gut and investigate assimilation.

They prepared it yesterday like this:

First they took a piece of Visking tubing 

After wetting it they knotted one end 

 Then tried to open up the other end

This is a fiddly job 

But once opened

 they added some glucose solution 

 and some starch solution

in equal quantities

and then knotted the other end 

 and put it into a boiling tube full of water.

This was left for 24 hours and then the inside and outside of the visking tubing was tested for starch and glucose. They found that the starch had stayed in the inside of the visking tubing while the glucose had spread so it was in equal quantities inside and out. Sorry no photos of the testing today, I was so busy issuing instructions I forgot!

 

 

 

 

 

8S get analytical

8S started their work on salt analysis with a little work on our old friend copper carbonate

First the mass of the copper carbonate was calculated



 The the test tube was heated

 While any gas given off had to bubble through limewater

If this went cloudy then it means carbon dioxide was released 

 The test tube needs to cool down

 after heating

then the mass of the remaining copper oxide can be found 

Plotting all of their results we found a good correlation between the two masses.

 

7C get digestive

In today's lesson 7C used the enzyme amylase to digest starch solution

First the starch solution was measured into a boiling tube

 then drops of iodine solution were pipetted into the wells on a spotting tile

 The iodine turns from orange to black with starch

 you need to have lots ready

 the amylase needs measuring out too

then mix it together 

 and start the clock

 Each group used a different amount of amylase solution

then tested the mixture every 30 seconds 

by adding a drop to one of the wells 

if it turns black there is still starch there 

 but if it stays orange then all the starch has been digested by the amylase

 the class found out that the more amylase you have

 the quicker the starch gets digested

20ml Starch with 12ml amylase - no black after one minute 

20ml Starch with 3ml amylase - no black after 8 minutes