Here's episode 4 of the blue marble!

Like the previous one I used two tables which allowed me to build more and bigger tricks. It is the chain reaction that has taken up the most space in my room since the beginning.

Some information about tricks:

- the slidings white dominoes: this one was so satisfying; the dominoes slide exactly after the marble has passed over them. It looks like a video game when a character walks over a bridge that collapses behind him. But how do dominoes slide? The slope is not steep enough to make this possible. The idea is to pour fine sand under the dominoes and all the way down the slide. With the sand, any object placed on it will slide even with a very slight slope. I discovered this by accident when I was trying to make a trick with sand and the objects, I put on the table always ended up on the ground. To keep them from slipping there are 3-hole reinforcement, the dominoes are placed on them, but when the marble passes, they move a little down, fall from the hole reinforcement and start slipping. This technique required a high degree of precision to be applied at each test. If it was too sensitive, they would fall before because of the vibrations of the previous tricks (like the iron ruler), and if it was not sensitive enough, they would stay at the top without moving. Getting one under control is already hard, but I had the good idea to put 3 of them in a row to make it even harder. On the other hand, when they were well put in the right position, they worked 100% of the time, it's just that the right position was very difficult to find.

- the red car: it's called a "retrofriction car", but I learned it afterwards, in the store I had to ask "you know the car that you pull back and then it goes forward", it took me an hour to find it. At first the car was supposed to go to the top of the table by pushing the ball vertically but the slope was too steep, so I had the idea to compress the marble between a domino and the car, which pushes it upwards

- the fidget spinner: yes, one more. I like the simplicity of this one, only the spinner and the marble, no strings or complicated things, just the weight of the marble that makes the path turn, and it works every time

- the helium balloon: helium is expensive and hard to find. But that wasn't the biggest problem. It is such a small atom that it passes through the plastic of the balloon, which deflates with time. When I inflated it he had enough strength to lift the marble for about an hour. The little trick was to over-inflate it and put a weight with blu-tack to compensate (when it had too much strength it would blow the ball out of the circuit). As a result, every time the balloon lost strength, I removed a little bit of weight, which allowed me to hold on longer with the same balloon. I still used 6 or 7 (I had the capacity to inflate 25). Oh and yes, I used toilet paper for the ramp, because it's light.

- the fan: this is the main trick of the video. All the previous tricks take up little space but the fan takes up the majority of the white table. I wanted a big trick to contrast with the rest and make it even more impressive. This machine was hard to film because you had to alternate between the small tricks where you had to be close to understand what was going on and the large angles for tricks like this one, also the marble goes fast.
This is the first time I use electricity in my machines (and not the last time considering all I can do with it). To start the fan the red marble falls on a button. This button is in balance between "on" and "off" which makes it very sensitive and a small shock is enough to tip it to one side. The fan is multi-use, it is used to make the marble go up with the elevator, and make it jump higher for the 2nd bounce to reach the other black platform. It caused a large part of the failures, not because of the fan, but the jump with the rubber band. The bounce remained a little random and it was necessary for the marble to land accurately, twice.

- coca/mentos : I always wanted to use the famous coca/mentos tricks, now it's done. You can notice that I used 3 mentos glued together because one was not enough (and I didn't test 2 because it cost me a bottle at each test). The first time it put coke everywhere, so I added the container at the bottom of the table to catch the liquid, and since there was the electrical outlet underneath, I think it's was good idea.

- the electric mixer: I couldn't make cakes for a month because it was glued to the table :(

If you read all of this, congrats, you're a true chain reaction fan. I'm going to try to post more regularly but I'm a great procrastinator (I bought the white table for this 4 months ago). The next video will probably be a screen link like Magnets and marble, It has been a long time. It will allow me to have fun with risky techniques that I can't do with one-take machines.