Signal Generator Linear Air Track Power Supply

Code SI130500

Developed in conjunction with physics teachers and designed specifically for education, this unit provides all the functionality you need for physics teaching. One really useful feature for those less familiar with using signal generators is that for basic use, you just operate two buttons: One for frequency and one for amplitude, that’s it!

Code TI68740

A superb quality air track, suitable for elastic and inelastic collisions, momentum, speed and acceleration measurement.

Code EL150308

A simple, robust and reliable power supply, ideal for basic electricity experiments. Offering stepped adjustment of both AC and DC with 1 V between the steps.

Making potassium manganate (VII) crystals (KMnO4)

Ingredients:

• Eye protection/gloves/apron (KMnO4 will stain skin and clothing)

• Saturated solution of KMnO4 - Solid hazards: Oxidising; irritant; respiratory irritant; environmental hazard. Solution hazards: irritant.

• Beaker

• Pencil (or similar)

• Cotton/thread

• Tweezers

Method:

2. Attach the cotton to the pencil with the free end hanging in the solution.

1. Pour the saturated KMnO4 solution into a beaker.

3. Place the pencil across the top of the beaker.

4 Leave for a few days for the crystals to grow around the cotton.

5. Pull out the cotton and pick off the crystals, using the tweezers, when they are the desired size.

Notes/tips:

The saturation point for KMnO4 is 6 g per 100 mL, so ≥ 6 g in 100 mL will give a saturated solution at 20⁰C You can use these homegrown crystals as a starting point for diffusion and convection current experiments.

Making EDTA solution in 1000 mL

Titrations involving EDTA: The disodium, dihydrate salt is commonly used for titration work (0.1 moldm-3 or 0.05 moldm-3 solutions are suitable). For accurate work see also details on standardising EDTA solutions.

Molecular weight 292.2438 g/mol

Ingredients:

• EDTA (ethylenediaminetetraacetic acid)

• Sodium hydroxide pellets

• Hydrochloric acid (2 moldm-3)

• Distilled or deionised water

• 1000 mL measuring cylinder

• 1000 mL beaker

• Magnetic stirrer

Method (to make 0.1 moldm-3 solution):

1. Add 29.22 g EDTA to approx. 800 mL of distilled or deionised water and stir (using a magnetic stirrer).

2. Check the pH. The pH needs to be 8 for EDTA to dissolve.

3. Add sodium hydroxide solid, a little at a time, until the pH reaches 8. (If it overshoots and becomes too acidic, add a little hydrochloric acid to bring the pH back to 8).

4. Once the EDTA has dissolved, make the solution up to 1000 mL with distilled or deionised water.

Health and safety for technicians

Health and safety in the department is everyone’s responsibility. Every member of staff has a duty of care and as such should never ignore anything that might put students or staff at unnecessary risk. Individuals will not be held liable in law for an accident/incident, unless they were acting negligently, or willfully disregarding health and safety guidance having been given the appropriate training.

It is your employer’s duty to organise appropriate health and safety training for new employees whether they are new to the school, the department, or even the specialism. You should be taken through procedures for evacuation, risk assessment and so on - this training can be given by a senior technician or department member tasked with such duties.

If your school or academy trust is a member of CLEAPSS or SSERC (Scotland) there is a wealth of helpful information pertaining to health and safety that you will have access to.

Tasks that require supervision and training before you can carry them out unsupervised include:

√ Fire training

√ Eye irrigation in the event of a chemical splash

√ Operating equipment such as fume cupboards/EHT power supplies/Van der Graaff/autoclaves and other pressure vessels

√ Biological and chemical waste disposal including microbial waste and hazardous chemical waste

√ Handling chemical spills

The list is extensive and can be found in CLEAPSS guide G234: Induction and training of science technicians.

In addition to specific training (that will occur as you meet these tasks over the course of your employment) general health and safety should always be at the front of your mind.

This includes consideration of:

Your own safety: Safety of others:

• Using Bunsen burners

• Working in the chemical store or preparing chemicals

• Moving heavy equipment

• Prioritising tasks when interrupted or asked to do something urgently. You can only work as fast as you feel safe. Never leave a task unfinished if it is unsafe to do so.

• Trip hazards in the corridor or lab (e.g., uneven carpet)

• Slip hazards (e.g., wet floors)

• Fire doors being propped open

• Missing fire extinguishers

All of these occurances need reporting to relevant staff members (or the site team) as soon as you see them. Do not assume someone has already noticed and reported it!