Using Data-loggers to speed up the process

Introduction to Data Loggers.

Experiments take time. And much of this time is often wasted trying to learn how to record. This is a very valuable skill but once learnt data-loggers can take over this chore and allow the student to do more learning and less recording.
Using state of the art sensors connected to a computer we can now carry out the experiments and pull out all the information about the process quickly and accurately and get to the learning point. Using these sensors we can also pull out other useful information which is otherwise not readily available to learn more about the processes. The data-loggers cover all aspects of Science and also cover all the A level Biology Chemistry and Physics.

The sensors are linked directly to the computer. They capture data every few fractions of a second and send this to the computer where the data is displayed in a table for the student to work on or more usefully as a graph to display the features of the experiment.

The data-loggers enable far more complex experiments to be carried out and in a fraction of the time taken to do the experiments manually. This is also good preparation for business where things are usually carried out by machine and the students can see for themselves how processes work in a more business like and professional manner.
Using this data-logging equipment gives the child an advantage over others so that they can become better scientists.

Schools opt for less subjects but better grades

This is a sample of some of the emails I receive

"My child wants to do triple science, but has been told that the school will only enter them for double, as they believe this will 'maximise the child's grades and therefore their life chances'.  i.e. they would rather the child got two As or A*s than risk getting 3 Bs." 

I agree.  This is a load of rubbish, but is a problem that schools are making on their own.

Very commonly schools believe that students cannot improve. 

Schools are ranked on what grades the students get. It is in your childs schools interest that your child takes fewer subjects with higher grades than taking more subjects and possibly getting a lower grade. 

The school can now only count the first time a student takes an exam for their performance figures.

This is often why this rule about double / triple science exists. The school does not want to have any poor grades. The schools are scared of  a child  getting lower grades which will lower the schools performance average.

It is in the schools interest that your child does less subjects with better grades and nothing to do with your childs progress.

It seems that schools are out for themselves and not putting the child first - just to get higher up a league table. What is the benefit to a school that has good league table results if it doesn't try to help children suceed

A use for Lego Znap A DNA Model

 I have some old Lego Znap. It was part of a Lego experiment to compete with K'Nex. Its not much use and after having a look in one of the science catalogs selling K'Nex as a DNA molecule I thought I would have a go making a DNA strand with it

Here are the results. an 8 base pair set - I didn't have any more connectors. The set can be twisted into a double helical structure and since the stuff was just lying around it has found a good use.

The Znap has four colours here red - green and black - yellow making the different base pairs.
It will do until I can get a much better model and that won't be K'Nex either.

Starch Amylase Experiment

I made up a starch solution  with 1/4 teaspoon  of starch dissolved in about 100ml of water I used soluble starch but corn starch will do or even the water from boiling potatoes.
I had a failure with the experiment the last time I did it with a student so I tried the same chemicals again to test to see if they worked. Into the first tube I added some starch and a few mls of a 1% Amylase solution. Into the next tube I put the same amount of starch and 2-3 mls of spit - I know this enzyme works.

After 20mins I took a sample of each of the tubes and added a squirt of Benedicts reagent and placed in a beaker of near boiling water for a few minutes. The left hand tube with the commercial Amylase powder enzyme turned the brown colour - confirming that the enzyme was working and converted some of the starch to maltose.

The middle tube went green showing that the Amylase in my mouth worked - slower - but some Maltose was made.

The tube on the right with just starch and no enzyme did not change showing that Starch does not react with Benedicts solution and there was no Maltose present in the starch.

So the Amylase enzyme does work and does convert starch to Maltose which is a reducing sugar (the Benedicts Test)
My spit works too albeit slower.
Now why did this not work for the student? I have no idea.

Kipps Apparatus

I bought a Kipps apparatus to generate Carbon Dioxide Gas or Hydrogen Gas. I don't need very much or make it that often so gas cylinders are a waste of time. It is a fascinating piece of equipment which is so simple to use.The Kipps generator was invented in 1844 by Petrus Jacobus Kipp and was used throughout the rest of the 19th and the entire 20th centuries for making gases.  Kipp generators are still being used in some places even now because of their ability to make a gas and then stop and then to be turned on again.
The Kipps apparatus is used to make a variety of gases such as Carbon Dioxide, Hydrogen and Hydrogen Sulphide. This is often why the Kipps apparatus was often left in a fume cupboard in the back of a classroom for all to see.
To make hydrogen gas some granulated zinc is put into the middle vessel by removing the  stopper.
Acid is then poured into the top vessel which is connected by a glass tube to the bottom vessel.
When the chemist requires the gas the valve in the middle chamber is opened and this allows the acid in the top chamber to force by air pressure the acid in the lower chamber into the middle chamber. The acid mixes with the zinc and there is a reaction. The zinc reacts with the acid and generates hydrogen gas. If the valve is open then the gas is collected often under water into a gas jar.
When enough gas has been collected the valve is turned off. The pressure in the middle chamber starts to increase and pushes the acid out of the middle chamber back into the bottom and also into the top chamber. When all the acid has been removed the reaction stops because there is no longer any acid to react with the zinc.
The Kipps apparatus is very simple to use, interesting to understand how it works and gives a good insight to how old fashioned ideas are still good to use today

Convection Currents in a beaker of water

 One of my A level students yesterday had never seen convection currents in water, so I set up this simple experiment for him. Into a large beaker I poured some cold water and at the bottom I placed a small coloured crystal.
I heated the water with a burner and watch as the water heated,  the water coloured by the crystal rose up in the beaker - not straight as the books suggest but in a more spiral direction until they reached the top when they spread out even more.

The water showed that it was less dense than the water around it because it was hotter and therefore it was lighter and rose to the surface - albeit not in a quite vertical direction.

There we are warm water rises and disperses the heat around the beaker from the bottom to the top.

New toys - old concepts - The Leslie Cube

A Leslie cube is a small hollow metal box with different painted sides. One is bare metal, the others are matt black, gloss black and gloss white.
The cube is filled with water and then heated until it boils.
Using an infrared thermometer we look at the temperatures  of the different surfaces. Each is a different temperature as seen in the pictures.

With a burner under the cube the water is heated until it is boiling. and the temperature of each surface is measured.
The bare metal surface came out as 49.3C

The Matt black surface came out as 97.9C

The smooth black surface as 95.9C

And the white surface as 97.0C

There is a difference. The bare metal was cooler by far. Now why might that be?