We are about to reach New Year’s Eve 2021 and the matter is not very clear if our idea is to meet with a huge number of people. It is possible that in the end we will spend it as a family. Why not do some experiments to pass the time? But not just any experiments, but Experiments to understand the world proposed by the disseminator Javier Fernández Panadero. All the quotes that follow are taken from this physicist’s book of knick-knacks.
And if you missed the 10 experiments to do with balloons, with these ten you now have a list of 20. Enjoy!
Material : sheet and marker.
“We are the last descendants of a long lineage that ran away when they saw a leaf move […]. Let’s say we are children of cowards and fortune-tellers with some success.” Our brain has evolved to make decisions even in the absence of data. One thing is the image we see and another thing is what we interpret. “If I see a person sitting at a table, I’ll assume they have legs even if I can’t see them.” In this experiment, a double-faced card is shown that magically changes its content… or maybe it is our brain that changes it?
Material: candle and lighter.
“Take a candle, it will come out better if it is one of those candles that when you blow it out it leaves a good thread of white smoke”. And it is that Panadero explains to us how to light the candle without bringing the lighter closer to it, only bringing it closer to the thread of smoke. “In this way, that white color of the smoke comes from flammable substances that have not yet been burned and that are likely to burn.”
Don’t even think about it, you have a safe bet with a €50 bill, although it is also worth it with another. And science says so, specifically kinematics. If you put the bill in your family member’s hand and drop it, will they be able to catch it? Watch the video and you will see that he will never be able to catch it. “In practice, he only takes it if he cheats, for example trying to guess when you are going to drop it.”
Material: An “empty” bottle, the cava bottle comes in handy. A ball of aluminum foil.
Put the bottle on its side and the small ball of aluminum foil in the mouth. Blow hard to try to get it in. What happen? Well, you can’t put it in. The result of this experiment is counterintuitive. “Being wrong is normal, being sure of your mistake is terrible.” The reason is explained in the video.
Material: A spoon, a pitcher of water, a bowl, a candle, a jar and a lighter.
Would you be able to blow out a candle without blowing on an object between the candle and your mouth? You can see it in this video, but what is the coanda effect?: “When a fluid in motion encounters an obstacle, it tends to stick, to a certain extent, to its surface, thereby varying its trajectory.”
Material: An empty can, a little water, a stove, some tongs and a bowl with ice and water.
Heat the can until the water begins to evaporate. You turn the can upside down (with the tongs) and put it into the bowl. Implode! “What has happened is that while the can was on fire, there was hot air and water vapor inside. When you cover it, when you introduce it a little into the bowl, the hot air cools, its pressure drops, and the water vapor condenses”. The can lowers the pressure inside, as it remains “somewhat empty”, so “the external overpressure is enough to violently squeeze the can”.
Material: An empty glass bottle, a glass of water and a coin.
Put the open bottle in the freezer and take it out when it is cold. Wet the mouth of the bottle and put a coin on it. Wait a moment and “you will see that the coin makes a little jump and sounds «blop». It will continue to do so for a while…” The reason for this behavior is explained in the video… paranormal? “There are people who believe that paranormal things happen to them because paintings move or fall in their house, until the day they realize that they are hanging above a radiator that produces an upward current of hot air.”
Material: Two shot glasses, a passport or any card that resists humidity, a little water and a little red wine.
It explains how to place the two shot glasses so that the wine passes into the water glass and vice versa. If they come together, they should mix. But, when “a liquid moves at a ‘low’ speed, it behaves like ‘sheets’, so that it can flow in contact with another fluid and not mix.”
Materials: A plastic bottle, a bag of oranges or similar and a jug of water.
He explains how to cover the bottle with the net and ensure that the water does not fall out of it even if it is turned upside down. Is it a magical network? “In water there are forces that hold the molecules together. […] They are forces that appear between hydrogen atoms of one molecule and an oxygen atom of another, they are called hydrogen bonds. […] on the surface [of the water] that attraction generates a “skin” with a certain tension, called surface tension, on which insects walk and bathers give us belly-thrusts”.
Material: Two forks, a toothpick, a match and a glass.
It’s the classic experiment of balancing two forks with a toothpick on the rim of a glass, but… with an interesting twist that leaves your mouth open. “In the video, we also make the flourish of burning part of the toothpick to make it clear to what extent it is stable with minimal support, all because the center of mass is under the fulcrum.” Do you dare to do it?