Teltron Tube

 I have been doing a lot of work recently with students doing A level Physics looking at the discovery of the electron and how electrons and behave in a magnetic field. This teltron tube is set up with Helmholtz coils to do just that.On the left a low voltage supply heats a wire so electrons are given off, and then on the right a high voltage supply attracts the electrons and fires them across the tube as a beam of electrons.

A Motor as a Generator

Working with a Westminster motor. The Motor can either be driven by a battery or can be spun and then the output measured on a galvanometer. Then the motor works like a generator, in this case a DC generator, and we can use Flemings Right Hand Rule to work out the direction of flow of the current Second Finger knowing the motion (Thumb) and the Direction of the magnetic Field First Finger.

How to make a Model of an Animal cell

A model of an Animal cell made of plasticine. In blue these are mitochondria, the nucleus is separate with a ball of DNA and some loose strands. in the foreground is some rough endoplasmic reticulum with some ribosomes making a protein from the mRNA.

Using an ice-cream container and a soap ball from a washing machine, and a bit of plasticine, here is a model of an Animal cell, created in just a few minutes. Many schools set this as a exercise so Lets have a go.

Requirements

1 used ice-cream container

1 soap dispenser for washing liquid

1 set of plasticine

Cling Film

Blue Mitochondria. - Make a boat shape and then with brown tubes of plasticine form the cristae the bumps and ridges inside. The mitochondria have DNA inside so make a ring of red plasticine and knot it up and place inside. A typical cell will have lots of these so make a few.

Centrioles: lots of rods of plasticine all the same size, bundled together to make a rod od rods.. Make two and place them at 90 degrees to one another.

Lysozome or Vesicle: A green semi sphere you can put shapes of purple protein in this if you want, or leave it empty to make a vesicle.

Endoplasmic reticulum: Pink plasticine rods all bunched up together.

Rough Endoplasmic reticulum - This is similar but I decided to use a different colour, white. The Rough endoplasmic reticulum is a roll of plasticine with branches and then loosely mixed together. Stick to this small black beads to make the ribosomes. The ribosomes are two small bead one slightly larger than the other on top on each other. Some of these have a roll of yellow plasticine in between the beads representing the mRNA. Coming out of the top of the bead is a purple piece of protein. Many ribosomes can be on one piece of mRNA.

Golgi apparatus: larger and larger plates of plasticine . Here I have separated them and put orange lipids in them.

The nucleus: Make some double rods of DNA. Here several two red strands are made and then loosely mixed together. I left one double strand out and made yellow mRNA ( 1 strand ) and put it next to the DNA double strand to show making mRNA from the DNA.

Finish it off by placing some cling film over the top to stop it falling out.