Question

why do seeds float over the mercury column?

short answer.
​

Answer 1

Answer:

Take a test tube and

completely fill it with mercury.

Invert it over a petridish which

is also filled with mercury.

There must be a continuous

column of mercury in the

test tube.

• Tilt the test tube slightly and

with the help of forceps

introduce 3 - 4 healthy

germinating gram seeds.

• Gently tap the test tube with

your finger nail/forceps so

that the seeds move upwards

in the mercury column.

• With a clamp fix the test tube

to a stand and keep the setup

undisturbed for two hours.

• Observe the setup.

• Introduce 3-4 KOH pellets in

the same way as seeds were

introduced. Observe the changes.

23-04-2018

104

Laboratory Manual: Biology

Observation

A space is formed at the top of the test tube due to downward displacement

of mercury. When KOH pellets are introduced, the gap slowly disappears

and mercury again fills up the entire tube.

Explanation: