Скачать или смотреть Lab equipment for heating, cooling, and incubating - what's what and which to use when

A lot of the experiments we do require us to “incubate” things - keep things at constant, specific, temperatures (sometimes with shaking or with controlled CO₂ and/or humidity, etc.). So we have a bunch of types of incubators and other equipment we can use to keep things hot or cold. Here’s a basic guide to some of this equipment you might find in a lab.

Note: the most common “temperature” we incubate things at doesn’t require any fancy equipment - room temperature! Sometimes abbreviated “RT” this is typically around 20°C but can vary greatly which can also cause experimental results to vary greatly if they’re temperature sensitive. So if your reactions are temperature sensitive, control the temp even if it’s close to room temp.

Hot or cold:
thermal cyclers - we often refer to these as PCR machines because we use them a lot for PCR (a method where we make lots of copies of a specific DNA sequence based off of a DNA template). They’re useful for that because they can get hot and cold really quickly, allowing for the cycling temperatures PCR requires. This also makes them useful for simple incubations at a large range of temperatures - as long as your samples are in those tiny PCR tubes! So it’s only useful if you have samples with volumes less than about 200μL
Thermal shakers (mostly used for heating, but some have cooling features that can go down to about 0°C) - these are basically temperature-controlled blocks with different size holes for various tube or plate sizes. The blocks are on an orbital shaker so you can shake things at various speeds (or you can turn off the shaking). The standard eppendorf tube holder size is great for the recovery/outgrowth step after a bacterial transformation (after sticking a plasmid into bacterial cells you want to let them recover in the absence of antibiotics before playing them).

Heating (in addition to thermal cyclers and thermal shakers):
heat blocks - similar to thermal shakers but lower tech - they don’t shake. Often these are simply metal blocks in sand with a heated base. The temperature on the older ones at least can be hard to precisely control, involving lots of knob turning and thermometer reading. But a cheaper easy option for when exact temps aren’t as big of a deal, such as when you just need to boil gel samples, etc. There are also newer digital ones that probably have better temp control but cost more (but probably still less than the ones that also shake)
Water baths - these are basically just temperature-controlled water buckets and they’re good if your samples are in irregularly shaped containers, like media bottles or stuff. Another nice thing about them is you can quickly take multiple samples in and out if you put the samples in styrofoam floaters or other racks. We use these a lot for heat shock steps during bacterial transformations as well as thawing or heating up various things.
Bead baths - these are similar to water baths but use metal beads instead of water. These are often used in place of water baths in cell culture rooms because they can be kept sterile more easily.
Plate incubators - these are basically heated chambers with shelves for holding Petri dishes of bacteria, plates of adherent cells, etc. They range in size but are often about the size of a mini fridge. But they’re warm (often 37°C) and some are CO₂- and humidity-controlled (mammalian cell culture typically needs this).
Shaker incubators - similar to the plate incubators in concept but have an orbital shaker platform instead of shelves. Good for growing suspension cultures (cells suspended in liquid food (media)) because the shaking allows for aeration so oxygen gets to even the cells that were at the bottom of the flask.
Heated magnetic stir plates: stir plates have spinning magnets - so when you place a magnetic stir bar in your sample and place it on the plate (and turn it on) the stir bar will spin and make the liquid in your sample mix. Some of these have heating elements too - but not all do so check before you plan to use one! Also be careful not to accidentally bump the heat knob and turn it on or up when you don’t mean to. And also never store items on a hot plate (even one that’s not currently on) - it can start fires. Those warnings aside, they can be really useful for helping you dissolve things that don’t want to dissolve and for controlling chemical reactions.

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