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An old couple is occupying theirs old house with their own well for drinking water. One day the water from the well stopped running, probably because of some problem in the well itself. Unfortunately, no one knows where the well is located.

From the pump, which is inside the house, 1.5 inch pipe goes approximately one meter underground and turns at right angle and continues in direction 'outside of the house' in horizontal direction. The well is filled with some material, and it is not clear, if is in the garden or under the house.

Suggest several possibilities of finding the well which are easy to realise.

Balloons often assume that the constellation of stars close to the horizon look bigger then when located high at the sky.

Perform a measurement on the Earth and decide if it is really misleading observation. Measure angular distance $α(t_{1})$ of two selected stars which are approximately above each other and angular distance $β(t_{1})$ of other two stars at approximately the same height above horizon (i.e. independent check in two separate directions) at the moment, when the stars are as low above horizon as possible. Later on, find the same stars as high as possible and repeat the measurement recording $α(t_{2})$ and $β(t_{2})$ parameters. Try to measure with the highest precision.

We will specially recognise if you are able from known catalogued coordinates of stars calculate its theoretical angular distance. Do not forget to describe used equipment and discuss pros and cons. Plot schematic sketch of the sky around the stars and record time, direction etc. of the measurement. Finally estimate errors of measurement and discuss and compare the results.

Measure the alcohol content in cheap table vine and compare the content to the value declared on the packaging.

One winter day Matous went for a run on to frozen fishpond. After several meters he was not able to run any more and he stopped. The ice had broken under him. Explain, why it lasted when he was running!

Measure the flash-point (the lowest temperature at which the substance ignite) of the refill for the cigarette lighter. As a bonus measure the flash-point for the ethanol or other organic compound.

For example use a resistive wire warmed up by the electric current and let the flow of the gas from the lighter to flow over it. To calculate flash-point use values of the voltage and current and known temperature dependence of the resistivity. Do not restrict yourself to this suggested experiment!

Warning: Fire can cause serious burns, please proceed with extreme caution!

The average temperature at the earth is $T$ = 287 K. What is going to be the average temperature $T'$, if the average distance between the Earth and the Sun shrinks by 1%?

It is few centuries since we know that the Earth spins around its axis. Measure the time, which is needed for the Earth to rotate 360° around its axis. Try to measure with highest possible accuracy. You can suggest and perform more than one experimental method. But, in each case do enough measurements to be able to do some statistic with the results.