If you can either find or have an old fridge, you can easily use the back of the fridge to re-make a solar thermal water heater that can easily burn your hands.
This method doesn’t use any actual solar panels but uses a reflective surface and the heater bars of the old fridge to heat the water, pretty incredibly simple yet very effective.
A word of warning, this panel works VERY WELL. We tested it on a very sunny day and within seconds the water coming out of the panel was hot enough TO SCALD. I burned my fingers. This very hot water is only formed when the water inside the panel is allowed to sit for about a minute without moving. If the water is moving (do to the gravity siphon) the water exiting the return pipe is about 110 degrees, and while hot, will not burn you.