Tutorial: How to Science
This tutorial will show you how to get Science, starting with the simplest science activities with just your Kerbonaut on up to mastering the use of all the Science modules. With this knowledge you'll plan missions better and build your craft to maximize the results of picking up stuff and looking at things in strange new places.
For Beginners: what is Science, anyway?
Science is making observations and getting the reports home. Too abstract? Then let's make a short tutorial: design the simplest ship possible, a plain Command Pod Mk1 and nothing else. Hit "Launch". Of course, that pod won't go anywhere, but it doesn't need to: on the launchpad, right-click the pod, select "Crew Report", and you're doing science! You cannot transmit the results, because your simple craft has no antenna. In order to get the data home, you need to recover your vessel.
Important Science Fact: whatever you do in the field, you won't get any Science Points until you return the results, either by radio transmission or by recovering the vessel (or Kerbal) where the results are kept.
Crew Report is just one Science Activity; your crew may also leave the pod and create an EVA Report or collect Soil Samples. Later you will also get dedicated science instruments like thermometers or the Mystery Goo™ Containment Unit.
If you paid attention during our brief tutorial above, you noticed that you got a "Crew Report from the LaunchPad" -- just getting you capsule off the pad will move it into a new biome where you can get a new report for fresh Science Points. Actually, Kerbal Space Center alone is made up of three different biomes; the rest of the planet is not as finely detailed, but Mountains, Deserts, Icecaps and so on are easy to make out from above. You will need to collect quite a few surface samples etc. from Kerbin before you can even consider going to the Mun.
On Mun and Minmus every large crater (or depression, respectively) is a biome to it's own, plus a few more in-between. The latter are nowhere near as obvious as desert and grassland are on Kerbin, but there are slight differences in the look of the surface. For fully detailed maps, refer to the Biomes article.
Some combinations of activity and situation ignore biomes and give the same result wherever performed within an SOI; these combinations are marked " Global " in the table below.
Getting Results Back Home
As said above: doing lots of science in the field will not suffice. Only when the results somehow find their way to your R&D department will you be credited with science points.
Transmission and Recovery Values
For every result, you have the choice to either transmit the data or to keep it. For most experiments, transmission will yield significantly fewer points than recovering the results -- so much should be obvious. The two bars at the bottom of that window carry a lot of information, though:
First example, Mystery Goo: The absolute length of the bars represents the total amount of Science Points that can be collected from that particular experiment, in this case that would be 13 points. The bright green line shows the fraction of points you will get for performing the experiment once; in this case, 10/13th or approx 77%. If you repeat that experiment, you will get 77% of the remaining three points, and so on. Every time you repeat that particular experiment and recover the data, you will receive ~77% of however many (or few) science points are still left. As a rule of thumb, repeatable experiments are pretty much depleted after the third time.
The blue bar indicating transmission value follows a similar pattern, but please notice how even the dark blue stops far short of the total amount. No matter how many transmissions you make, you won't receive more than 30% of the available points. Once you are above the 30% threshold (eg, because you already returned one container), further transmissions will be worthless. The Mobile Processing Lab MPL-LG-2 can boost that number a a little (more on that below), but the fact remains: transmissions alone will get you only so far.
For comparison, an EVA Report: Whether you transmit or return the data, you will get the full science points all in one go. That kind is often called "non-repeatable experiments", although "no need to repeat" would be more precise. You may of course repeat this; filing the results more than once won't get you any more Science Points, though.
Recovering the results while leaving the equipment: Taking and Storing Data
All results are kept somewhere. If your Kerbal takes a surface sample, he carries it on himself at first. The moment he enters a pod or capsule, the result is transferred from Kerbal to capsule. A message on the screen notifies you of this, though it fades pretty quickly.
If your research is based on equipment, like thermometers or the Mystery Goo™ Containment Unit, the results are on said equipment. Probably the most convenient means of recovering these results is to just recover the science modules, but this is not the only way: a Kerbal can take the data (right-click during EVA, while in close proximity to the equipment in question) and subsequently transfer them to a pod, capsule, or some other modules. Simple experiments (e.g., thermometers) will then be available for immediate re-use; more complicated ones (e.g., Mystery Goo) will need to be cleaned out. The Lab is the only means of doing so during a mission. Still, once the data has been taken off them, the spent modules may safely be left behind.
Getting and staying close enough to effect an transfer can be a hassle sometimes, even on the ground, much more so in space. Having ladders to cling to makes this much easier.
Kerbals can also take data from one pod and move it to another: that's important when you want to make an Apollo-Style Mission where the Lander Module and the Return Vessel are two distinct spacecraft.
Most modules have only a limited capacity; typically, command pods can only take "one of each": one surface sample from here and one from there is possible, but if you want to take home two surface samples from the same site you need to bring two pods. Incidentally, it is not necessary to board a capsule only to transfer the data, you can again do this by right-click while being close to it. Putting data onto a module from the outside (i.e. without boarding the module) will store only as much data as the module can take, the remainder stays with the Kerbal.
Kerbals can take an unlimited amount of data from modules, even if that data includes several soil samples and EVA reports.
If you transmit data, you will implicitly "take" it from a module without the hassles of EVA. The other effects regarding re-usability and the possible need to clean out the module are the same, regardless of whether you take the data manually or by transmission.
Mobile Processing Lab MPL-LG-2
The Mobile Processing Lab MPL-LG-2 improves the value of science data before transmitting it; it has no effect on data kept aboard. Crew Reports and EVA Reports have no penalty on transmitting them, so lab processing doesn't benefit these two. The others typically improve by 50% (if the standard Transmit Value for a given experiment is 20%, the Lab pushes this to 30% and so on). While quite a boost, this still leaves a lot of unrecovered Science Points, so you probably still want to bring data back home.
For others, it can squeeze out points from reports that at first have "+0.0 Science" value to transmit.
However, the Mobile Processing Lab MPL-LG-2 can also store infinite amounts of scientific data - even multiple copies from the same experiment in the same situation & biome.
Both cleaning and processing required a certain amount of time and electric charge. Cleaning an experiment requires the same amount of energy as processing its report data.The Mobile Processing Lab MPL-LG-2 can also store multiple copies of scientific data - even those from the same experiment in the same situation & biome. For example, a lander could conduct three material studies with separate SC-9001 Science Jr. units, rendezvous and dock with a ship containing a Mobile Processing Lab MPL-LG-2, then have a Kerbal on EVA "Take Data" from each SC-9001 Science Jr. and place it in the lab. This must be done once per piece of data, as a Kerbal can only store one type of unique data at a time. Most experiments can be 'maxed out' in a single trip by recovering three or four samples.
Refer to the main article for ramifications and usage scenarios.