When I think about my early childhood, there is one picture that comes up from time to time: It’s my grandfather standing before the so called “weather station”, a wooden panel with three brass gauges: a thermometer, a hygrometer and a barometer. Then my grandfather gently knocked against the glass lid of the barometer with his knuckle and checked the barometer again. As a child I was convinced he woke up the little worker inside, who in return checked if the weather would become fair, rainy or if it was changing. This made perfect sense to me, because I knew there was a special force responsible for the weather: the weather fire dwarfs. After the evening news the news anchor would say “And now the weather fire dwarfs for tomorrow”. It was much later that I asked my mom and she explained to me that it wasn’t the “Wetterfeuerzwerge” (weather fire dwarfs), but the “Wettervorhersage” (weather forecast). Until then, I was convinced that being a weather fire dwarf was just a job like being a firefighter, a baker or a teacher. They looked out for the weather and made assumptions on how it was going to be. It also made perfect sense that this job was done by dwarfs, given the small instruments they needed to operate in.

You might wonder where I’m heading to with those seemingly random childhood memories? Now, my grandfather certainly did neither wake up the little weather fire dwarf, nor did he perform some other kind of magic. He just made sure the barometer, which had a small metal box called an aneroid for measuring the pressure inside, was showing the tendency. When you tap them, the pointer will move to the current pressure, giving you an indication if the air pressure is rising or falling. He also knew that the little markers that read “very stormy”, “rain”, “change”, “fair” and “very dry” were not to be take literally. In winter “fair” weather often meant it became very cold. He not only looked at the barometer – he also knew how to interpret what he saw.

Fast forward to 2018 I struggle with explaining the use and the accuracy of sensors to colleagues. I can’t fight the feeling that digital has somehow taken a toll on our imagination and our expectations towards instruments. It’s especially true for hygrometers, as humidity is far more complicated to measure exactly than temperature ¹. A digital hygrometer usually provides you with two digits behind the comma. So instead of reading a little above 50% on the analog hygrometer it provides you with a straight 51.23 % relative humidity. That’s astounding. Sadly, it doesn’t mean what people think it means. Because it seems to provide such an exact figure, people assume it’s more accurate than the analog reading of grandpa’s old weather station. But it isn’t necessarily so. If it’s a very good digital humidity sensor with a 1.5% accuracy the reading will mean it’s somewhat 50 to 52ish. If it is a more common sensor with a given 5% accuracy it tells you that it can be anything along the lines of 46 to 56% ²

But why are they giving two digits behind the comma anyway, is this just a fancy feature? Yes and no. For that, we have to understand the difference between accuracy and resolution, both specifications you will find when you are buying a datalogger or sensor. What we just talked about is the accuracy. The resolution is often higher than the accuracy. Your humidity sensor might have an accuracy of +/- 2% RH, but a resolution of 0.1. This seems like a contradiction at first, but it isn’t. Let us imagine a little weather fire dwarf who is able to feel how wet it is. He says: “It’s 52%”. Now, while we saw that this can mean anything between 50% and 54%, if we send him out again, he will be able to tell us if it is becoming wetter or dryer than before. And he will be able to tell us more detailed than he can do it with the general humidity. He is able to say: “It’s getting damper, now it’s 52.1%.” So, while the digits behind the comma mean nothing in terms of general humidity, they can help us understand where the climate of a room is heading to and how severe the changes are. If you measure every 5 minutes and get a reading of 52.1%, 52.3%, 52.2%, 52.1%, 52.2% and 52.1% over half an hour it will tell you something else than a series that reads 52.0%, 52.2%, 52.3%, 52.4%, 52.6%, 52.8%. While both series can still mean it’s 2% more or less humid, the tendency of the second series shows that something is going on which makes the room damper. Think of the resolution as a measurement that helps you to see change, just like grandpa tapping on that old barometer.

Next up, we will ask the question if sensors really read the temperature and humidity of a room.
Here comes the 2nd part…

Angela

Growing up in the middle of Europe my earliest Easter memories are joyfully searching for Easter Eggs in the garden. Many years later a recurring task in my professional life is searching for things that are not where the database says they should be. For this Easter I thought I’d write about the differences:

Searching for objects is not joyful

While as a child the search for the Easter Eggs is full of joy, the search for an object is all but that. You search for an object because it is needed, often needed fast, for a research request, loan or exhibition. There is time pressure and if you don’t find it, it has consequences. It can mean a whole lot of work for other people, like curators having to search for alternative objects that convey the same message as the original object. It can mean that whole parts of an exhibition must be changed because they were designed around this special object. It can also mean that a researcher can’t answer the question s/he is working on.

Objects are not hidden on purpose

Other than Easter Eggs no one hides objects on purpose. While a small portion is really stolen, most are lost because people miss to record or communicate location changes (we already looked at this in Failures in Figures). The reasons are multifold: thoughtlessness, laziness, arrogance (“That’s not my job”), confidence in the own abilities to remember everything, the belief that “I just take it out now and put it back in immediately”. No traits of the Easter Bunny but of many museum professionals.
Recently I discovered an additional reason why object locations are not updated: magical thinking. The belief just because there is Wi-Fi in the storage and the objects are barcoded a magical superpower knows exactly where each object is. Sorry folks, that’s not how it works.

Looking in all the right places

While searching for Easter Eggs is often unsystematic or just starting at point X and ending at point Y of the garden, searching for objects requires a different approach. If your storage has 3,000 square meters and much more shelf space, you can’t just search everything. And you can’t just go into the storage looking for the object. Instead, the first thing you do is a hands-off approach. You think about what most likely happened to the object.

A mindful use of energy

As a child on Easter morning it’s great to run into the garden full of energy and search for those eggs. As a museum professional with a tight schedule and a lot of tasks on your plate you have to be more mindful about how you will approach the search. You have to weigh the time you can invest in the search against the likeliness of finding the object.
If the object can be retrieved with just a few phone calls, everything is fine. If the object is needed next week and the last storage location is a place that doesn’t exist anymore (i.e. because you disassembled the shelves or moved into another storage location 10 years ago) it’s probably better to inform the researcher or curator immediately and ask her or him to look for an alternative, if possible. If there is a high likeliness of the object being in a pile of boxes that don’t have proper location entries, it’s probably best to work through this pile updating all locations – you will save yourself a lot of time for future requests.

Make sure you know that you don’t know

Remember as a child searching the same place twice because you forgot whether you have looked under that tree? You should make sure this doesn’t happen to you when you search for an object. The most important thing is to mark an object as “location unknown” as soon as you discover it isn’t where it is supposed to be. That way everyone knows the object is not accessible at the moment and can already think about alternatives. It also helps you to keep an eye on all the objects with “location unknown”: Is their number in the database decreasing, chances are you are doing a good job as collections manager. If the number increases, chances are there are problems in your collections management and logistic workflow and you might want to take a closer look to find the underlying issues.
That you should tick off the things you already did to find the object on your list should go without saying.

I hope the only thing you have to search for now are real Easter Eggs.
Happy Easter, all!
Angela

First you need to decide if you make a documentation of your whole museum or if you split it into different collections. That depends how large your museum is and if different people are responsible for different collections.

Overview of the collection

1. Elevator Pitch: Imagine a very important person is visiting your collection. They know nothing about it. You have 30 seconds on the elevator to tell them the most important facts.
   Describe your collection in three sentences. (Normal sentences, not scientific-paper-five-comma-sentences). Important are : Content of the collection, size, significance.

   On your way to the storage there are a few polite questions. Now you have a bit more time to answer, but stay focussed: Give an overview, do not go into details of collection concepts or the donor’s biography. That will come later.

2. Collection in context: Is your collection part of a larger museum collection? Is there any way to distinguish your collection from the others? (separate storage, different inventory number, classification,..)
3. Significance of the collection: How important is your collection in comparison to the other collections in your museum/to similar collections in other museums? What are the main differences?

Maria Scherrers

Maria Scherrers is museum specialist with degrees from HTW Berlin and the University of Leicester. She spent most of her working life so far in company museums and collections. She is fascinated by the way our everyday life is changed by brands and how that influences our cultural history and what we will be collecting in the future. In the mean time she is a consultant for company that wish to build and use historic product collections.
She spends her little free time on her family and on politics.
www.historicalassetmanagement.de