I always considered a checklist, a checklist, so I was interested to learn the distinction between two types of checklists: Read-Do and Do-Confirm.

A Read-Do checklist might be prepared in advance for several potential possibilities. You check off the tasks as you do them, like following a new cooking recipe. They may be geared towards helping people understand what they should be doing and in what order and helping them remember key steps in unusual or unplanned scenarios. So, for example, if a plane develops a particular type of rare fault, such as an engine failure, a Read-Do checklist could be pulled out for that scenario. The pilot and crew can use it to make the most of others' past experiences and failures. Even with training, given the situation's relative rarity, and especially if a serious situation might interfere with normal thinking, a Read-Do checklist helps steer the crew to safe outcomes without relying solely on training and memory. The calm security and simplicity of steps of a checklist can be just what's needed.

A Do-Confirm checklist is more of an aid to memory to make sure nothing gets missed. It's a safety net for normal operation catching lapses in memory. In principle, we know what to do, so we run through those steps from experience and memory and use the Do-Confirm checklist at a designated pause point to ensure we didn't miss anything. The WHO Safe Surgery checklist has helped save 1,000s of lives.

Because a simple checklist can never account for every unexpected occurrence in complex environments—for example, healthcare, aviation, building a skyscraper, or software projects—both checklist types can benefit from items that require a communication step. An item can just be to ensure that all those with the relevant knowledge have discussed things. It's a simple and powerful way to improve outcomes across a wide range of unexpected scenarios.

I learned about the simple power of checklists, the two types, and the resistance to adopting them—from Atul Gawande's, The Checklist Manifesto: How to get Things Right.

Two types of checklists: Read-Do, Do-Confirm

The siphon, or syphon, is a simple device that uses only a tube to seemingly pump water from a higher spot to a lower one. It's ingenious because once you start the siphon by filling the pipe to below the height of the upper reservoir level, it will continue draining the water, pulling it over the hump and towards the collection below without further help.

Most of us use siphons several times daily, as there are often two at work in the standard toilet. Sometimes there's one in the flush mechanism—one push of the handle to start the siphon drains the water from the reservoir until it runs out. And you can flush a toilet using the second siphon by pouring enough water directly into the bowl to push the water over the bend in the pipe to start it— think how the water drains by itself almost completely before filling up to the level of the bend once again. It's a clever way to power a toilet flush with just the press of a button or turn of a handle. They also minimise leaks and control the flow by running the water uphill.

We set up a greywater siphon to drain water from the bath and showers to a water butt in the garden. To get it started, we connected the end of the hose in the garden to a tap and ran water back up the hose until it shot out the top. Then, dipping it in the water, turning off the tap, and putting the end in the water butt, like magic, the siphon pulls water out of the bath until it's empty.

Surprisingly, a few effects are at work in a siphon, and its mechanism is debated. They can be made to work in a vacuum and even spray liquid upwards with the right setup.

I read that it is from the ancient Greek siphōn meaning a tube or pipe, often for drawing wine from a cask—that would be a decent situation to start the siphon by sucking on the end.

Siphon

It's easy to want to complain at the weather. The trouble is, it doesn't have any effect on it.

Complaining at the weather