Scenarios of experiments are available under the Creative Commons Attribution 3.0 Poland licence (CC BY 3.0 PL). Some rights are reserved to the Copernicus Science Centre. The works were created as a part of the Young Explorer’s Club Programme, conducted by the Copernicus Science Centre with the use of means of the Polish-American Freedom Foundation. It is permitted to use the content freely – provided that this information will be preserved, including the information about the applied licence, held rights and Young Explorer’s Club. Contents of the licence are available at http://creativecommons.org/licenses/by/3.0/pl/.