Laboratory Natural Science 2º ESO

LABORATORY CCNN 2º ESO

Name and surname: ____________________________ Table-Student: ______ Date: ________

SPORANGIA IN FERNS

In ferns, spores are produced inside the sporangia. These are grouped in the underside of the leaves (fronds) forming the sorus. Mature spores fall to the ground,and as they germinate they form the gametophyte, a little heart-shaped plant which produces male and female gametes.

Objective:  To see sporangia of ferns under the microscope.

                                                                                                  

Sporophyte with sorus

MATERIALS

- Leaves of ferns with sorus.                       

- Slides.

- Cover slips.

- Needles with handle.

- Lancets.

                                                      



PROCEDURE

1. Scrape the sorus with the lancet or needle and put the scraping material on the slide . Add a drop of water and put the cover slip on.

2. Put the slide under the microscopy and observe it with the lowest magnification. Every sporangium consists of a filament and a capsule where the spores are found.

3. Notice ​the capsule which is surrounded by a ring of cells with thick walls. When these cells dehydrate they contract, then the capsule breaks and the spores fall down.

ACTIVITIES:

1. How is the reproductive cycle of ferns called? _________________________

2. What is the name of the ferns leaves? __________________________________

3. Are spores unicellular or multicellular organisms? _____________________

4. Are spores for sexual or asexual reproduction? ___________________________

5. Draw what you see and write down the names and the total magnification of the drawing.

Total magnification = Ocular lens (Eyepiece) x Objective

LABORATORY CN 2º ESO  

Name and surname: ________________________ __Table/Pupil: ___ Date: __________

 WEIGHT – ARCHIMEDES’ PRINCIPLE

The weight of a body is the force which the Earth has on the body. It is measured in Newton, N.

Inertia is directly related to mass. The mass unit in the SI is the kilogram (kg).

P = m · g

All bodies submerged in a liquid or gas experience a vertical upward force, called upthrust, E,  which is equal to the weight of the volume of liquid displaced by the body.

Objectives: Differentiate weight from mass; to learn how to use the force metre and to verify the Archimedes’s principle.

Material needed:

-       Force metres.

-       Precision digital scales.

-       Spherical and cylindrical bodies of metal.   

-       Stands with base, rod and holders.

-       Beakers with water.

-       Pocket calculator.

Procedure:

1.  Measure the body mass and write it down on the table below.

2.  Weigh the object with the force metre, and write down the reading (P) in Newton.  

3.  Lower the object hanging from the force metre into the water. Note the new reading in the force metre; it is the apparent weight, P’.

4.  Work out the upthrust with the formula  E = P – P’

5.  Use the formula of the weight to calculate “g”.

6.  Complete the table below:

Body	Weight (N)	Apparent weight (N)	Upthrust (N)	Body mass (kg)	g (m/s2)

QUESTIONS:

a)    What is the relationship between upthrust and buoyancy?

b)   Define the upthrust?

c)    Write down the formula you have used to calculate “g”?