Newton’s first law says that the tableware will remain motionless unless acted upon by an outside force. When the tablecloth is pulled slowly, the tableware matches its low rate of acceleration and moves along with it.

The explanation is that air exerts force on the cardboard from below and this force is more than that exerted on the cardboard by the water. So the card is pushed up and does not fall.

When the glass is lowered in the water, air is trapped inside of the glass because of the water pushing up from below. Air is less dense than water so it is able to stay on top of the water. The paper towel will not get wet as long as the air stays in the glass.

Answer: The water is being absorbed, or soaked up, by the paper towel material through a process called capillary action. Paper towels are permeable and porous, meaning that they contain small spaces that both liquid and air may pass through.

Capillary action occurs because water is sticky, thanks to the forces of cohesion (water molecules like to stay close together) and adhesion (water molecules are attracted and stick to other substances). Dip a paper towel into a glass of water and the water will “climb” onto the paper towel.

Paper is made of cellulose, which water molecules like to cling to. As a result, paper readily absorbs water. Paper towels are especially absorbent because their cellulose fibers have empty spaces—tiny air bubbles—between them.

The water moves up the paper towels through a process called capillary action. The paper towel is made from fibers and the water is able to travel through the gaps in the fibers. The gaps in the paper towel act like capillary tubes and pull the water upward.

The Science Behind the Walking Water Experiment Essentially, the adhesive force between the paper towel and the water are more powerful than the cohesive force inside the water itself. This results in the paper towel pulling the water up.

The adhesive forces between the water and the fibers of the paper towel are stronger than the cohesive forces between the water molecules. As a result, the water travels up and across the paper towel out of one glass and into another.

Molecules in a liquid have enough energy to move around and pass each other. The food coloring you add to the water is pushed around by the water molecules. Since the molecules in warm water move around faster, the food coloring spreads out quicker in the warm water than in the cold water.

The colored water travels up the paper towel by a process called capillary action. The water is able to defy gravity as it travels upward due to the attractive forces between the water and the cellulose fibers. The water molecules tend to cling to the cellulose fibers in the paper towel. This is called adhesion.

Air is less dense than water so it is able to stay on top of the water. The paper towel will not get wet as long as the air stays in the glass. If you tip the glass (even slightly), the air trapped in the glass will rush out in the form of bubbles. Water will then rush in and the paper towel will get wet.

Mercury does not wet glass – the cohesive forces within the drops are stronger than the adhesive forces between the drops and glass. When liquid mercury is confined in a tube, its surface (meniscus) has a convex shape because the cohesive forces in liquid mercury tend to draw it into a drop.

Mercury causes capillary depression with an angle of contact of about 1300 in a clean glass in contact with air.