2 experiments using water

Magic pepper run

Materials needed

→A shallow bowl or plate

*Water

*Black pepper (or chilli powder)

*Liquid dish soap

*A cotton bud

Method

1) Fill the bowl with water.

2) Sprinkle pepper or chilli powder evenly on the water surface. It should float.

3) Touch the water with a clean cotton bud or finger first. You can also wear a clean kitchen glove and do these steps. You will notice that nothing will happen.

4) Now put a drop of dish soap on the cotton bud or finger. Touch the centre of the water gently with the soapy bud or finger.

5) You will notice that the pepper “runs away” to the sides of the bowl.

What happens?

Water has something called surface tension, which acts like a thin skin on its top. Pepper floats on this ‘skin’, but when the soap touches the water, the surface tension weakens and pulls the pepper away.

Walking water

Materials needed

*5 clear cups or glasses

*Water

*Food colouring (3 colours)

*Paper towels

Method

1) Arrange cups in a line.

2) Fill every alternate cup with water (1st, 3rd, and 5th).

3) Add different food colours to each filled cup, such as red, yellow, blue.

4) Fold paper towels into long strips.

5) Place one end of a paper towel in coloured water and the other end in the empty cup next to it.

6) Do this between all cups. Wait for 1 to 3 hours.

7) You will observe that the water slowly travels up the paper towel, and drips into the empty cup. The colours mix in the empty cups and create new colours like orange and green.

What happens?

Water slowly travels up the paper towel because of capillary action. Paper towels have tiny holes, which makes water move through these tiny spaces.