Pruning Fingers (61 Brilliant Biology Experiments)

You will need:

1. 2 large bowls
2. Water
3. Marbles
4. 4-6 volunteers
5. Stopwatch
6. 2 empty vessels

Find out why our fingers begin to wrinkle when
kept in water, by following this experiment.

INSTRUCTIONS

1. Make half the volunteers you have soak their hands in bowls of water until their fingertips begin to wrinkle.
2. One half of your volunteers have pruned/wrinkled fingers, take the two bowls and fill them with water.
3. Drop 15-20 marbles into the water. Place an empty vessel next to each of the 2 bowls.
4. Divide your volunteers into 2 groups. Group A—pruned fingers and Group B—normal fingers.
5. Ask one member from each group to remove the marbles one at a time from the bowl and place it into the empty vessel.
6. Once they are ready, start your stopwatch and time the two volunteers.
7. Note down the time taken by each group.
8. Repeat the same experiment with the remaining members from both groups, each time using only one member from each group.

RESULT

You will notice that Group A will be slightly faster than Group B. Research shows that our sympathetic nervous system causes the blood vessels in our fingertips to constrict, as a reaction to the water, resulting in wrinkles which act like treads on tyres, giving us a better grip under water.