Pour air

Fill a large washbasin with half a basin of water, soak a glass in the basin, fill it with water, and then buckle it upside down under the basin bottom. Put the other glass upside down in the water, and don't let it touch the bottom of the basin (you can see that the water doesn't come in because the air occupies all the space in the glass). Lift the first glass slightly, move the second glass to the front of the first glass, make it slightly inclined, and make the mouth of the glass next to the mouth of the first glass from below. When you tilt the second glass, the air inside will become bubbles and rise to the first glass, squeezing out the water there, so the air in the second glass will "pour" into the first glass.

Experimental principle: Because air is insoluble in water and much lighter than water, the air in the second glass is sucked into the first glass by the surrounding water and atmospheric pressure.

Mysterious table tennis

Glue the ping-pong ball to one end of a 30 cm long rope with tape. Hold the other end of the rope, take the ping-pong ball under the tap, unscrew the tap, let the tap water rush on the ping-pong ball, and then slowly lead the rope to one side and leave the tap water. Will table tennis leave the tap water with a rope? No, table tennis is not out of water, but it seems to be "attracted" by water. Soon, the rope formed an angle with the water column of tap water.

What is the reason? The pressure of the water washed on the table tennis ball is much smaller than that of the surrounding air. Therefore, atmospheric pressure constantly pushes table tennis to areas with less pressure.

Unbreakable paper

Put a thin board (90cm× 100cm) on the table, and leave a board with a length of 10 cm exposed outside the table. Then put four newspapers on that part of the board on the table, and smooth the layers of newspapers by hand to make them close to the board and desktop. Then hit the exposed part of the board with a fist or a wooden stick. In this way, even if the thin board is broken, the newspaper will not fly into the air.

Why? According to the calculation, an ordinary newspaper is about 0.2 square meters, and the atmospheric pressure is 2 tons. It can be seen that the air can exert nearly 2 tons of pressure on the spread newspaper. Obviously, you can't pry it.