GETTING ON WITH ENGLISH IN THE LAB 2n ESO: Study of movement

Study  of a movement  through  space-time  graph

 Objective:

 Trying to simulate a uniform rectilinear movement (URM)

Material

• A plastic graduated cylinder

• Water

• A Litlle ball made of plastilin

• A chronometer

Procedure:

Fill the graduated cylinder with water

Let intervals of 10 cm to 50 cm.

Drop the ball of plastilin and note the time it takes to get through  the point of 10 cm.

Repeat 3 times

Drop the ball of plastilin and note the time it takes to get through  the point of 20 cm.

Repeat 3 times

Calculate the average, so that  data will be more reliable

Note the data in a  space-time table

Space  x (cm)
Time  (s)

Time Average           ______                    _______               ________  

Represent the space-time graph

Questions:

1.       Does the average speed remain constant?

2.       If there are variations, offer  an  explanation that justifies them

3.       The results are close to what was expected for a uniform rectilinear movement?    Why?

4.       If we did the  experiment in air instead of water what kind of movement  did the ball have? How would the graph  space-time be? And the graphic speed time?

GETTING ON WITH ENGLISH IN THE LAB 2n ESO: 2+2=4 (BUT NOT ALWAYS)

The molecular-kinetic theory

OBJECTIVE:

• Understanding the molecular-kinetic theory.

INTRODUCTION:

The  molecular-kinetic theory of matter is a theory that explains the properties and behaviour of the various states of aggregation of matter.

The molecular-kinetic theory is based on three assumptions:

1. The matter consists of very small particles, almost invisible unless you have an electronic microscope.

2. The particles do forces of attraction between them that held together: In the solid strength is very large; in liquids, moderate and gases, very small.

3. The particles are in constant motion: the solid particles hardly move, vibrate only. The gas particles move independently of each other, and the liquid is given an intermediate situation. Remember that the higher the temperature of matter, its particles vibrate more.

MATERIAL:

1. A graduated cylinder of 100ml

2. 2 graduated cylinder of 50 ml

3. chickpeas and rice

4. Ethanol

5. Water

PROCEDURE AND COMMENTS:

This experience seems to defy the laws of mathematics.

i. Mix 50 ml of chickpeas with 50 ml of rice. What is the volume of the mixture?

ii. How can we explain this fact?

iii. If you mix 50 ml of water with 50 ml of ethanol, what do you think will be the final volume of the solution?

iv. Take this mixture in a agraduated cylinder. What is the volume of the solution?

v. What relationship do you think there might be between this and the previous experiment?

vi. Justify from the molecular-kinetic theory the fact that the volume of the solution is not 100 ml.

vii. Does it happen the same  if we do the  experiment with two immiscible liquids like water and oil?

GETTING ON WITH ENGLISH IN THE LAB 2n ESO: Hooke´s Law

Robert Hooke was a famous scientist, born in 1635. He most famously discovered the Law of Elasticity (or Hooke’s Law)

Hooke’s Law is a principle of physics that states that the force needed to extend or compress a spring by some distance is proportional to that distance. The law is named after 17th century British physicist Robert Hooke, who sought to demonstrate the relationship between the forces applied to a spring and its elasticity.

This can be expressed mathematically as

                                                     F= kX, 

 F is the force applied to the spring (either in the form of strain or stress)

 X is the displacement of the spring

 k is the spring constant

Objective:

Knowing the existence of Hooke's law, its working and its applications

Observing  graphically how the length of a spring increases in proportion to the force

applied to it.

Determining  the elastic constant of a spring.

Material:

A dynamometer

A balance and a rule

Procedure:

1.       Prepare a clamp stand with a ruler

2.       Put he dynamometer

3.       Calculate the weight  of an empty pencil case

4.       Put different objects inside the case of 100g , 200g, 300g …. and read their weight

5.       Make a table like this:

Mass (g)
Length (cm)

6.       Make a graph  (mass:x axis and length : y axis)

7 Calculate  the  spring  constant for every  measure

                  

                                               F=    Kx

LEARNING SCIENTIFIC VOCABULARY : 2n ESO

                                         ANGLOSAXON SYSTEM MEASURE


THE ENGLISH TEACHER HELPED US GIVING  A PRESENTATION . WE COULD HAVE  SOME INFORMATION ABOUT THIS SUBJECT SO WE WERE WORKING ON IT!!!


LET´S SEE OUR ARTISTS!!!

GETTING ON WITH ENGLISH IN THE LAB 2n ESO;Extraction of chlorophyll pigments

                                         

;

 The following procedure is used by chemists to know which substances are in certain products.

It is called chromatography, due to the coloured bands that  are obtained in the experience.

 Each color is characteristic of a substance, 

This technique allows determining the kind and amount of substances.

In this case try to see the pigments that are in green leaves.

1. Mash  the green leaves in a mortar , which may be for example, spinach, chard ...2. Add a little alcohol and continue crushing the mixture. (The amount of alcohol should be small).3. Filter the liquid obtained and collect it in a test tube. • This solution contains the chlorophyll.4. Take a narrow strip of filter paper, approximately 0.5 cm wide. Put a drop of the liquid obtained in  the end of the strip,  Let it dry.Then add another small drop.You will obtain a small  and concentrated stain.5.Then, put the paper strip into a test tube, Pour about 2 cm³ of  solvent. Do it as indicated by the picture below, so that the stain is a centimeter above the level of the solvent.                    
        
6. After a while, by  capillarity  the solvent will go up through  the filter paper, dissolving the green stain  and forming bands of color.The chromatogram presents an orange stain above (xanthophyll )and a green one below (chlorophyll.)

Questions:
1.When you crush the leaves with alcohol to catch  the chlorophyll , which  method are you  using  to separate?

2. Then we filter the liquid obtained. How do you say this method? For what purpose  that?

3. Finally we do a  chromatography to separate the different pigments in the leaves. Why do the different bands appear?

4. Draw the chromatogram obtained.

GETTING ON WITH SCIENCE IN THE LAB 2n ESO. Mass measures

	Science Department     2on ESO		MARK
MASS MEASURES
NAME:		Group:	Date:

OBJECTIVES:

• Measuring the mass of different substances.

• Handling the balance.

INTRODUCTION:

The mass is the amount of matter that something has.  The most important units are the gram (g) and kilogram (kg).

The instrument for measuring the mass is the balance. There are different types: 

       

Before using a device to measure we need to know some concepts: sensitivity, precision and accuracy.

• Sensitivity: determines the minimum measuring a magnitude that can make the device.

• Precision: A balance is precised when  the measures taken are always the same.

• Accuracy: approximation between the actual value and measured.

MATERIAL:

·         A beam balance

·         A top-loading balance

·         A pencil

·         A rubber

·         A steal ball

·         30 cm3 of water (1 ml = 1 cm3)

PROCEDURE:

With the top-loading balance:

Turn it on and wait for 0.

Measure the mass of the container in which you  will put the substance. Press the button "tare". Now only the substance in the container will be weighed.

Observe and write down  the value of weight.

Repeat the same procedure three times.

Do the same for each substance.

With the beam balance:

Put the thing in a plate and the different weighs on the other until you arrive at an equilibrium

Observe and write down  the value of weight.

Repeat the same procedure three times.

Do the same for each substance.

OBSERVATIONS

Write down the result in the table below:

	Mass  (top-loading balance)	Average (g)	Mass(beam balance)	Average (g)
Rubber 1
Rubber 2
Rubber 3
Pencil 1
Pencil 2
Pencil 3
Steal ball 1
Steal ball 2
Steal ball 3
Water 1
Water 2
Water 3

CONCLUSIONS:

a) How sensitive are the balances that you used

b) With  the results given, do you think  that the measures that you made are accurate

c) Which  balance do you think is more accurate?

  

SELF-EVALUATION:

Did you like the practise?  YES/NO

Did you learn new things? YES/NO

Do you think you have been working well? YES/NO

Did you work well with your group?