Chapter 13: Practical Physics

What safety precautions you need to take with electricity?

• Before making any changes to the wiring in your circuits, always switch off the power or disconnect the battery.

• Never make a direct connection across the terminals of a battery. - - Don't put wires or tools where they might connect across the terminals.

• If a mains appliance is faulty, switch off the power and pull out the plug. Don't change the fuse. Ask the laboratory technician to deal with the fault.

What safety precaution you need to take with glass thermometers?

Following:

• Don't put glass thermometers where they can roll off the bench.

• Keep glass thermometers away from bunsen flames.

• Mercury, used in some thermometers, is toxic. If a thermometer breaks and mercury runs out, don't handle it: ask for help from your lab assistant/technician or teacher.

What safety precaution you need to take with glass tubing?

Following:

• Never attempt to push glass tubing (or glass thermometers) through a hole in a bung. The laboratory technician has a special tool for doing this.

• Always handle hot glass tubing with tongs. Rest it on a heatproof mat; don't put it straight on the bench.

• Hot glass tubing can stay hot for a long time. Give it plenty of time to cool down before you attempt to pick it up.

What are common working safety precautions?

You need to be able to do the following:

• Handle materials and equipment safely.

• Follow instructions carefully.

• Change how you carry out each step of an equipment, depending on what happened the time before.

What safety precautions you need to take with safe support?

• When clamping a test-tube, don't overtighten the clamp. And make sure that the clamp has soft pads to touch against the glass. This also applies when clamping a glass thermometer.

• In experiments where you have to suspend a load, make sure that the supporting clamp stand is stable enough to take the heaviest load you will be using. You may need to weigh it down for this, as shown in the diagram on the left.

What safety precaution you need to take with bunsen burners?

Following:

• If a bunsen burner is alight, but not in use, always leave it on the yellow flame setting so that the flame can be seen.

• Make sure that bunsen and tripods have a heatproof mat underneath.

• Give a hot tripod plenty of time to cool down before attempting to move it.

• Don't attempt to move a tripod when there is a beaker resting on it.