A variety of types of electrode is available. The metallic springs are electrical conductors, known as electrodes. The tin dendrite grows in the direction that the electric current flows through the solution from one spring towards the other. Tin is a metal that precipitates (forms a solid) as solid, elemental tin. Near to one of the springs, a tin reduction reaction takes place: Once connected, the electric current starts to flow through the solution. Why does the tin dendrite grow?īy attaching wires to the springs on the Petri dish edges we connect the tin(II) chloride (SnCl 2) solution to the batteries. This is why the "+" electrode will eventually dissolve if you don't disconnect it. Meanwhile, the "+" electrode itself, which is made of iron, will give some of its electrons to the "+" wire, leaving some iron ions floating around. tin atoms with two electrons missing) will gladly accept some electrons at the "-" wire and will turn into metallic tin. wires), a variety of chemical reactions can take place: by the "-" electrode some particles will capture the electrons that are pouring out, and by the "+" electrode some particles will give their electrons away. When such a pump is connected to a solution via "electric hoses" (i. e. Other experimentsīatteries are basically electron pumps: they suck electrons in with their "+" and pump them out from their "-". If the batteries don’t work, and you did everything correctly, then dispose of them in accordance with the environmental standards of your region. Insert the new batteries into the battery holder, paying attention to the polarity.Īfter use, immediately remove one battery from the battery holder. You need to connect "–" of the battery to the "–" of the battery holder, and "+" to "+". There is almost always a spring on the negative side of the contact in the battery holder. The convex end of cylindrical batteries is their "+".Īnd the polarity must be indicated on the battery case or label! The flat end of the cylindrical batteries is their "–". If these characteristics conflict, one of the batteries can start to overheat, which can potentially result in a battery leaking and damage to the equipment.Ĭarefully examine your batteries to determine their polarity and location in the battery holder. Batteries made by different manufacturers can have different specs (voltage, amperage, etc.). We highly recommend that you use the same brand of batteries in your devices. Substances in non-reclosable packaging should be used up (completely) during the course of one experiment, i.e. A solid table with a heat resistant top should be provided It should be well lit and ventilated and close to a water supply. The area surrounding the experiment should be kept clear of any obstructions and away from the storage of food. Particular attention should be paid to the safe handling of acids, alkalis and flammable liquids. The supervising adult should discuss the warnings and safety information with the child or children before commencing the experiments. The instructions should enable supervisors to assess any experiment to establish its suitability for a particular child. This experimental set is for use only by children over 12 years.īecause children’s abilities vary so much, even within age groups, supervising adults should exercise discretion as to which experiments are suitable and safe for them. Only carry out those experiments which are listed in the instructions. The incorrect use of chemicals can cause injury and damage to health.
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