Science Jrs and goo can be "reset". But you'll need:
- One Kerbal to EVA with
- One science lab (this will require 2 Kerbals to operate)
Then just follow these instructions:
Make Science - Do experiments, and click "Keep Data". Don't transmit.
Collect Science - EVA, next to your parts, click on the equipment that you kept data in and select "Collect data".
Store Science - You can take this data straight to capsule to store it in or store it in science lab, only matters if you plan to enhance data for additional transmission, its best to bring it back though. While in EVA you can click on capsule door or lab door close to you and select "Store data" to put the experiment in the capsule/lab.
Clean parts - Now that the experiments are inoperable (Goo and Sci Jr), they MUST be in the same ship as the lab, meaning you must dock the ship containing the experiments to the ship containing the lab. You can rightclick on the lab and select "Clean experiments". You may have to do this several times, as it will give up if you run out of energy, but it will restart from the % it left off from when you get more electricity.
You can remove the science from capsule by EVAing and right clicking the door of the capsule.
Make sure you return to Kerbin with the science.
Edit: the above may be useful for some other hapless kerbal so I'll leave it there and answer your question correctly.
Scott Manley is playing version 0.22 of KSP. This was the first version with science and some of the parts and functionality from the current version of the game simply didn't exist. One of those is pretty much all science parts. Before version 0.23 you could spam various science parts getting less and less science each time - and that's what Scott is doing.
The video in question is from November 2013 (a year ago). The game is very different from then and spamable science modules has long since been removed.