1. Beating mercury heart Balázs Végh Jurisich Miklós High School KŐSZEG

2. A szív képét javasoljuk ide 70 times a minute 100,000 times a day 3 billion times within 75 years

4. Mercury heart Chemistry Physics Fun

5. Substances sulphuric acid solution (H 2 SO 4 ) potassium-dichromate solution (K 2 Cr 2 O 7 ) mercury (Hg) Apparatus a needle or nail watch-glass overhead projector (OHP)

6. Procedure of experiment drop of mercury on the watch-glass just barely reaches the drop it’s taking triangular and spherical shapes by turns drop is at rest

7. Explanation I. The shape of the drop is determined by the surface charge. Increase of surface tension  decrease of surface  drop contracts Large surface charge  small surface tension  drop goes flat

9. Explanation II. mercury atoms are oxidized: 6 Hg+Cr 2 O 7 2- +14 H + =3 Hg 2 2+ +2 Cr 3+ +7 H 2 O H 2 SO 4 oxidizes the iron: Fe+2 H + =Fe 2+ +H 2 or the dichromate ion oxidizes both the iron and iron ions: Cr 2 O 7 2- +2 Fe+14 H + =2 Cr 3+ +2 Fe 3+ +7 H 2 O resp.: 6 Fe 2+ +Cr 2 O 7 2- +14 H + =6 Fe 3+ +2 Cr 3+ +7 H 2 O

10. Explanation III. reactions take place very quickly  needle becomes negatively charged mercury gains electrones from the needle Hg 2 2+ ions are reduced to metallic mercury mercury and iron are reoxidized  the process starts from the beginning periodic increase and decrease of the drop

11. The mercury vibrates Stoppes quickly after one touch – looses energy (damped vibration) Each contact provides energy - periodically f outside = f natural  RESONANCE Within the mercury stationary waves are produced