PHYSICS EXPERIMENTS

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LEARNING BY DOING

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Wednesday 2 August 2023

HOW TO REMEMBER THE CONCEPTS EASILY - POWERFUL MEMORY TECHNIQUES

 Memory techniques, also known as mnemonics, are powerful tools that can help us remember concepts for an extended period of time. These techniques tap into the brain's natural ability to associate and recall information using visual, spatial, and auditory cues. By leveraging these cognitive processes, memory trainers can assist individuals in enhancing their memory and retention abilities. In this comprehensive guide, we will explore various memory techniques and strategies that can aid in remembering concepts for more extended periods.


I. Understanding Memory and How It Works:

Before delving into memory techniques, it's crucial to understand the basics of memory and how the brain processes information. Memory is the process of encoding, storing, and retrieving information. The brain encodes information through neural connections, which are strengthened when we repeat or elaborate on the content. Storage of information occurs in different areas of the brain, including the hippocampus and cortex. Lastly, retrieval involves accessing the stored information when needed.

The memory process can be improved through regular practice, attention, and specific memory techniques. These techniques capitalize on the brain's ability to create associations, visualize, and use patterns to enhance memory performance.

II. Memory Techniques:

  1. Visualization:

Visualization is a powerful technique that involves creating mental images to represent the information being learned. By associating the concept with a vivid image, the brain forms a stronger and more memorable connection. To use this technique effectively, follow these steps:

a. Create a mental image: Convert abstract concepts into concrete and memorable images. The more unusual and vivid the image, the easier it will be to recall.

b. Associate the image: Connect the mental image with the concept you want to remember. This association enhances recall.

Example: To remember the term "photosynthesis," visualize a plant basking in sunlight while taking photos with a camera.

  1. Chunking:

Chunking involves breaking down complex information into smaller, manageable chunks. By grouping related items together, it becomes easier to remember and recall larger concepts.

a. Identify key elements: Identify the essential components or themes within the information.

b. Group related items: Arrange the elements into logical groups or categories.

Example: Instead of trying to remember individual dates in history, group events into significant periods or movements.

  1. Method of Loci (Memory Palace Technique):

The Method of Loci is an ancient memory technique that involves associating information with specific locations in a familiar place (memory palace). It capitalizes on spatial memory, which is particularly strong in most individuals.

a. Choose a familiar place: Select a familiar location, such as your house, and mentally walk through it to create a memory route.

b. Associate information with locations: Place the information you want to remember at different points along the route, linking concepts to each location.

c. Visualization: As you mentally walk through the memory palace, visualize the information at each location.

Example: To remember a list of grocery items, mentally place each item in a specific room of your house as you walk through it.

  1. Acronyms and Acrostics:

Acronyms and acrostics are memory aids that use the first letters of each item in a list to create a memorable word or phrase.

a. Create a word or phrase: Use the first letters of the items you want to remember to create a new word or phrase.

b. Form an association: Ensure the acronym or acrostic is related to the content, so it's easier to recall the items it represents.

Example (Acronym): To remember the colors of the rainbow (red, orange, yellow, green, blue, indigo, violet), use the acronym "ROY G. BIV."

  1. Storytelling:

Storytelling is an effective way to remember interconnected concepts. It involves creating a narrative that links the information you want to retain.

a. Identify key elements: Determine the main concepts you want to include in your story.

b. Create a narrative: Develop a coherent story that connects these concepts logically.

Example: To remember a list of vocabulary words, create a story where each word is used in a sentence, and the sentences flow naturally.

  1. Spaced Repetition:

Spaced repetition is a study technique that involves reviewing information at increasing intervals over time. This method strengthens memory and promotes long-term retention.

a. Create a study schedule: Plan regular review sessions at specific intervals (e.g., daily, weekly, monthly).

b. Review strategically: Focus more on concepts that are challenging to remember, and gradually extend the time between review sessions as you gain mastery.

  1. Mind Mapping:

Mind mapping is a visual technique that helps organize information and create connections between related ideas.

a. Start with a central concept: Write the main concept or topic in the center of the page.

b. Branch out: Create branches extending from the center, representing sub-topics or related concepts.

c. Add details: Continue branching out with more specific details and examples for each sub-topic.

Example: To organize the components of a complex system, create a mind map with the central system name and branches for subsystems, processes, and elements.

  1. Use Sensory Associations:

Engaging multiple senses can enhance memory. Associate information with sensory cues like smell, taste, touch, or sound to make it more memorable.

a. Incorporate sensory experiences: If possible, associate a particular scent, taste, texture, or sound with the concept you want to remember.

    Example: If learning about a specific type of fruit, associate its taste, texture, and aroma with the concept.

    1. Link Method:

    The link method involves creating a story or chain of associations between items in a list.

    a. Make associations: Link each item in the list to the next one through a story or a visual connection.  b. Create a chain: Connect each item in the list to the previous one, forming a chain of associations.

    Example: To remember a shopping list (e.g., eggs, milk, bread), visualize eggs cracking open, milk pouring over the eggs, and the bread absorbing the milk.

    1. Analogies and Metaphors:
    2. Using analogies and metaphors can simplify complex concepts by relating them to familiar and understandable ideas.

      a. Identify similarities: Find similarities between the concept you want to learn and something you already know well.

      Create the analogy: Develop a comparison between the two, explaining how they relate to each other.

      Example: If learning about how a computer's CPU works, compare it to the brain's role in processing information.

      1. Active Recall:

      Active recall is a memory technique where you actively retrieve information from memory rather than passively reviewing it.

      a. Test yourself: Cover the material and try to recall the information from memory.

      b. Review and correct: After attempting to recall, review the content to check for accuracy and identify areas of improvement.

      III. Memory Improvement Strategies:

      1. Stay Organized:

      Maintain a structured and organized study routine. Have a designated study area, keep notes and materials well-arranged, and set clear study goals.

      1. Use Visual Aids:

      Utilize visual aids like diagrams, charts, and graphs to complement text-based information. Visual elements can enhance understanding and memory retention.

      1. Teach Others:

      Teaching or explaining a concept to someone else can reinforce your understanding and memory of the material. It also allows you to approach the topic from different perspectives.

      1. Get Sufficient Sleep:

      Adequate sleep is essential for memory consolidation. Aim for 7-9 hours of sleep each night to enhance memory retention and recall.

      1. Regular Review:

      Practice regular review sessions to reinforce your memory

    Tuesday 30 May 2023

    HOW ARE SPHERICAL MIRRORS MADE AND THEIR TYPES

     

    Spherical mirrors are typically made by shaping a reflective material, such as glass or metal, into a spherical shape. The specific method used depends on the material and manufacturing process involved. Here are a couple of common methods for creating spherical mirrors:

    1.  Glass Spherical Mirrors:


    ·         Glass mirrors are often made using a technique called "silvering." In this process, a glass blank is first prepared by grinding and polishing it to achieve a smooth and uniform surface.

    ·         A thin layer of reflective material, such as aluminum or silver, is then deposited onto the surface of the glass. This can be achieved through various methods, including chemical deposition or physical vapor deposition.

    ·         After the reflective layer has been applied, a protective coating is typically added to prevent tarnishing or scratching. This coating is often a clear layer of paint or lacquer.

    ·         The shape of the mirror is determined by the grinding and polishing process, which involves carefully shaping the glass into a spherical form.



    SMART WATCHES






    1.   Metal Spherical Mirrors:




    ·         Metal mirrors, such as those made from aluminum or other reflective metals, are often created using a process called "spin forming" or "spinning."




    ·         A metal disc or blank is placed onto a spinning machine, which rotates the blank at high speeds.




    ·         As the blank spins, pressure is applied, either mechanically or through the use of specialized tools, to gradually shape the metal into a spherical form.




    ·         Once the desired shape is achieved, the mirror surface is typically polished to enhance its reflectivity and remove any imperfections.


    CONVEX MIRROR USES:

    Convex mirrors, also known as diverging mirrors, have several practical uses due to their unique optical properties. Here are some common applications of convex mirrors:

    1. Safety and Security: Convex mirrors are widely used for safety and security purposes. They are commonly found in parking lots, garages, and driveways to provide a wide-angle view and eliminate blind spots. They allow drivers to see oncoming traffic or pedestrians, reducing the risk of accidents.

    2. Retail and Surveillance: Convex mirrors are employed in stores, supermarkets, and other retail environments for surveillance and theft prevention. By strategically placing convex mirrors, store owners can monitor different areas of the store, minimizing blind spots and deterring shoplifting.

    3. Traffic and Road Safety: Convex mirrors are installed at intersections, curved roads, and blind spots to enhance road safety. They provide a wider field of view, allowing drivers to observe approaching vehicles, pedestrians, or cyclists, which helps in preventing collisions.

    4. Industrial and Warehouse Settings: Convex mirrors find extensive use in industrial and warehouse settings. They assist in monitoring production lines, machinery operation, and large storage areas where visibility may be limited. These mirrors increase safety by allowing workers to observe their surroundings, including potential hazards or obstacles.

    5. Home Security: Convex mirrors can be utilized in residential settings for enhancing home security. By placing convex mirrors strategically near entrances, driveways, or windows, homeowners can monitor activities outside their property and detect any suspicious movement.

    6. Decorative Purposes: Convex mirrors are also used for decorative purposes in interior design. They can create an illusion of a larger space by reflecting light and expanding the perception of the room. These mirrors come in various shapes and designs, adding an aesthetic element to the decor.

    7. Roadway and Parking Signs: Convex mirrors are sometimes integrated into road signs to provide additional visibility to drivers. They can be used to reflect oncoming traffic or display warnings at blind spots, improving driver awareness and safety.

    8. Rearview Mirrors: The passenger-side mirrors in automobiles are often convex to provide a wider field of view. Convex rearview mirrors help drivers see the surrounding traffic, reducing the blind spots and improving overall safety.


    CLICK HERE TO SEE CONVEX MIRROR WATCHES 



    Tuesday 25 August 2020

    GENERAL KNOWLEDGE SECTION : SEARCH AT ONE PLACE.......FIND AT ONE PLACE

     GENERAL KNOWLEDGE - USEFUL for  ALL COMPETITIVE EXAMS...........

    PHYSICS

    1. From the daily life situation, What is more convenient rolling of stone on a sloping road than to lift it vertical upwards ? 

    Ans: the work done in rolling a stone is less than in lifting it. 

    2. Which is the phenomenon observed in absorption of ink  by blotting paper?
    Ans: Capillary action

    3. Give the unit of Nuclear size and it is the name of a scientist.
    Ans: Fermi

    4.  Why the star appears to move from east to west?
    Ans: The Earth rotates from West to East.

    5. What is the value of ' one KNOT' ?
    Ans: 1.852 Km/hr   and 'knot' is the unit of speed


    CHEMISTRY:

    1. What is the composition of a soap?
    Ans: Potassium and Sodium salts with fatty acids.

    2. Say something about 'Selenium'?
    Ans: non metal, conductor

    3. Which metal remains in liquid form under normal conditions?
    Ans: Mercury

    4. What is the mass of electron?
    Ans: 9.1 X 10 ^ -31 Kg.

    5. Which fuel is used in rockets?
    Ans: liquid oxygen


    Sunday 10 May 2020

    REFLECTION AT CURVED SURFACES - CONCAVE AND CONVEX MIRRORS - A COMPLETE STUDY

    SPHERICAL MIRRORS ----  CURVED SURFACES  - KEY CONCEPTS




    Let us look at the below diagram, reflection at plane surfaces i.e. at plane mirror. All the laws of reflection at plane surfaces are valid and applicable to spherical mirrors also.

    plane mirror reflection property



    SPHERICAL MIRROR ?


    The mirrors which have curved surface are known as Spherical mirrors, these mirrors are part of a hollow glass sphere.

    CONVEX MIRROR AND ITS TERMS


    The spherical mirror is said to be convex if the bulged surface is made smooth and the inner surface is silvered. 






    CONCAVE MIRROR AND ITS TERMS 





    The spherical mirror is said to be concave if the bulged surface is silvered and the inner surface is made smooth.




    SPHERICAL MIRRORS AND TERMS RELATED :

    APERTURE: The surface of the mirror from which the reflection take place is called its aperture.

    POLE: The central point on the surface of the mirror is called its pole (P)

    CENTRE OF CURVATURE:

    The centre of the sphere of which the spherical mirror is a part is called the centre of curvature of the mirror.

    RADIUS OF CURVATURE::

    The radius of the sphere from which the spherical mirror is a part is called the radius of curvature of the mirror.

    PRINCIPAL AXIS:

    The line joining the pole and the centre of curvature is called the principal axis of the mirror.

    FOCUS: (F)

    The point on the principal axis where rays incident parallel to the principal axis converge to reappear or to diverge from after reflection is called the Focus of the spherical mirror.


    FOCAL LENGTH (f):

    The distance of the Focus from the pole is called the focal length (f) of the spherical mirror.

    REAL AND VIRTUAL IMAGES:


    An image formed by the actual intersection of light rays is called a real image. A real image is formed on the screen.

    If the rays of light responsible for an image do not actually intersect, the image is called virtual image.

    Virtual image cannot be formed on the screen, as no light reaches where the image appears to form.





    Observe the following ray diagram when a parallel light incidents on a concave mirror and understand the reflection concepts........





     IMAGES FORMED BY A CONVEX MIRROR:

    Irrespective of the position of the object , The image formed by the convex mirror is always virtual and erect but when we compare the the size of the image, the image size  is always diminished.  

    PRINCIPAL FOCUS OF A CONVEX MIRROR
    The principal focus of a convex mirror, which is divergent mirror,  is a point on the principal axis of the mirror, at which all the incident rays parallel to the principal axis appears to diverge after reflection from the mirror.


     The principal focus of the convex mirror is virtual and always lies behind the convex mirror. 


    observe the above ray diagram when parallel rays incident on both concave mirror and convex mirror and observe the principal focus. 


    from the above ray diagrams, write down the characteristics of the image formed.






    MIRROR FORMULA:


    1/v + 1/u = 1/f

    From the mirror formula, if we observe, we can understand that how the object distance,u, and image distance,v, are related to the focal length.  The distances are measured from the pole only. Pole to object is u, and pole to image is v, 

    MAGNIFICATION BY SPHERICAL MIRRORS:
    Generally, we can understand that the magnification is the increase in the image size with respect to the size of the object which is produced by spherical mirrors.  The magnification is calculated by taking the ratio of height of the image to the height of the object ---- hi/ho.  It can also be calculated by the negative ratio of the image distance to the object distance.

     What can we understand from the magnification ?

    *** when 'm' value is positive it tells us image is virtual.
    *** when 'm' value is negative it tells us image is real.



    logical question combining mirror formula and magnification


    FIND OUT THE OBJECT DISTANCE (u), when the magnification produced is 'm' and focal length is 'f'.

    solution:    

    mirror formula is :  1/f = 1/v + 1/u



      magnification is m = -v/u   so  v=-mu

    substituting the 'm' value in formula:

      1/f = 1/-mu   + 1/u

    1/f = 1/u(1/-m + 1/u)

        simplifying,   u = f/m(m-1)

    critical thinking problems:


    1. Suppose that you are given a concave mirror of focal length 15 cm.  Then, 

    a) To get the magnification m=1, where the object is needed to be placed
    b)  When the object is placed at 30 cm, write the characteristics of the image formed.
    c)  Your friend told that the image formed at infinity, where would be the object is placed.



    2. When a student is performing experiment with concave mirror of focal length 20 cm, then he observed that the size of the image is reduced to 1/3rd of its size of the object.  Calculate the object distance in this situation. 






      

    Wednesday 29 April 2020

    COMPLETE STUDY MATERIAL ON CHEMICAL EQUATIONS - FOUNDATION TO ADVANCED

    CHEMICAL REACTIONS - CHEMICAL EQUATIONS

    INTRODUCTION:


    In our daily life we all know about physical changes and chemical changes, all these changes are observed in our day today life.  We observe ice converts into water vapor and vice versa.  In this example, the changes in the states of matter are observed and heat may be gained or released.  Similarly, burning of wood also example.

    CHEMICAL REACTION:

     Chemical reactions represent the processes in which a single substance or substances undergo change to produce new substance or substances with different or new properties are called 'CHEMICAL REACTIONS'.

    For example: When potassium nitrate gets heated potassium nitrite and oxygen are formed.  This is a chemical reaction since potassium nitrate changes into potassium nitrite and oxygen, these are new substances.

    A chemical reaction consists of REACTANTS and PRODUCTS.

    From the above example, potassium nitrate is called Reactant and potassium nitrite and oxygen are the products, since the substance which takes part in  chemical reaction is called Reactant and a new substance formed or substances formed in a chemical reaction, called products.

    FIND OUT THE REACTANTS AND PRODUCTS from the following:

    Calcium carbonate ----->  Calcium oxide and carbon dioxide

    Sodium combines with water to get sodium hydroxide and hydrogen

    HOW THE REACTANTS ARE TRANSFORMED INTO PRODUCTS ??????


    Initially, the compounds or molecules break down into atoms and these atoms take part in the reaction then products are formed by new bonds formed between the atoms.



    CHARACTERISTICS OF CHEMICAL REACTION:

    How can we understand that there is a existence of chemical reaction and it took place, by observing the characteristics we can understand that there is a chemical reaction observed ......

    1) When metals react with acids, we can observe there is evolution of Hydrogen gas.

    2) Formation of precipitate when two solutions are mixed, the precipitate is a solid substance separated from the solution.  For example, lead iodide is a precipitate formed when lead acetate aq.solution combined with aq. sol. of potassium iodide.

    3) Some times we observe the emission of heat such reactions are exothermic reactions, we know that when Calcium oxide is added to water, and sometimes the equipment becomes cold when ammonium chloride mixed with barium hydroxide.  These are called endothermic reactions.

    CHEMICAL EQUATIONS  Vs CHEMICAL REACTIONS


    We can understand with an example :

    CaCO3 is the formula of Calcium carbonate and CaO is calcium oxide and CO2 is carbon dioxide.

    The above is a chemical reaction, when it is represented with formula and symbols, that notation is known as chemical equation.

    How can we write a chemical equation ??????

    * the reactants and products in the reaction should be written with their formulae  or symbols.

    * when more than one reactant or product, then + symbol is used

    * an arrow mark is used in between reactants and products, the arrow mark also tells us in which way the reaction is taking place.

    What information is conveyed by a chemical equation ???


    * we understand the reactants and products in the reaction, and their number of atoms

    * we can calculate the masses of the compounds or molecules in the reactants and products

    * we come to know the number of moles of the reactants and products.

    EXAMPLE:

                   When we observe the formation of water from hydrogen and oxygen :

    There are :

    four hydrogen atoms, two oxygen atoms gives two water molecules

    two moles of hydrogen and one mole of oxygen to give two mole of water

    four grams of hydrogen and thirty two grams of oxygen to give 36 g of water

    we can also calculate number of atoms and volumes also.

                 2 H2 + O2 ------> 2 H2O



    HOW TO MAKE A CHEMICAL EQUATION MORE INFORMATIVE ???


    Generally,  a chemical equation do not represent any thing other than the reactants and products, but to make a chemical equation more informative, one has to represent :

    * states of the reactants and products, s, l, g, aq.

    * the evolution of gas with upward arrow line and precipitate with downward arrow line

    * if heat is liberated, then in the products + heat should be written

    * if heat is absorbed, then in the reactants + heat should be written.


    TYPES OF CHEMICAL REACTIONS:

    1) COMBINATION REACTIONS

    2) DECOMPOSITION REACTIONS

    3) SINGLE DISPLACEMENT REACTIONS OR SUBSTITUTION REACTIONS

    4) DOUBLE DISPLACEMENT REACTIONS


    WHAT IS THE DIFFERENCE BETWEEN BALANCED CHEMICAL EQUATION AND UNBALANCED CHEMICAL EQUATION ??


    BALANCED CHEMICAL EQUATION : When the number of atoms of each element on both sides is  equal then the equation is said to be balanced chemical equation.

    UNBALANCED CHEMICAL EQUATION: When the number of atoms of each element on both sides is not equal, then the equation is said to be unbalanced chemical equation.

    HOW TO MAKE AN EQUATION A BALANCED EQUATION - STEPS TO BE REMEMBERED:

    ** must know the formulae of compounds or molecules of reactants or products and the subscriptions in the formulas should not be altered at any cost.

    for example: always the calcium carbonate is CaCO3 and Hydrogen molecule  is H2 only.

    TRIAL AND ERROR METHOD OF BALANCING A CHEMICAL EQUATION:


    STEPS:

    1) COUNT EACH TYPE OF ATOMS ON BOTH SIDES

    2) IDENTIFY THE MOST COMPLICATED FORMULA AND COUNT THE NUMBER OF ATOMS OF EACH ELEMENT

    3)  BY TRIAL AND ERROR METHOD, CHANGE THE NUMBER OF ATOMS ON BOTH SIDES TILL THE NUMBER OF ATOMS ON BOTH SIDES EQUAL.

    EXAMPLES OF UNBALANCED AND BALANCED EQUATIONS:

    1) KClO3 ---> KCl + O2

     After balancing,

       2KClO3 ----> 2 KCl + 3 O2



    2) CaCO3 ---> CaO + CO2



     3) AlCl3 + Ca(OH)2  ----> Al(OH)2 + CaCl2


        2 AlCl3 + 3 Ca(OH)2  ----> 2 Al(OH)2 + 3 CaCl2




    4) Al + H2SO4 ----> Al2(SO4)3   +  H2

    After balancing:

    2 Al + 3 H2SO4 ----> Al2(SO4)3   +  3 H2



    How to balance a chemical equation? with algebraic expression method.


    A chemical equation tells us the type of reaction between different reactants. Chemical equation gives the states of the reactants and products.  One can calculate the amount of products required for required amount of products.

    To balance a chemical equation, very interesting method is algebraic expression method.


    for example:  C3H8 + O2 -----> CO2  + H2O




    The above reaction is to be balanced using algebraic expressions

    step 1) the coefficients of Each reactants and products assumed to be a,b,c,d,...

                        aC3H8 + b O2 -----> c CO2  + d H2O

    step 2) identify and count the number of elements on both sides of the reaction

                        carbon: 3a = c

                        hydrogen: 8a = 2d

                        oxygen:  2b = 2c + d

                        

    step 3) let us assume a=1, then simplify the equations for other variable values

                            c = 3,     2d = 8   then d = 4             if d=4 and c =3 then 2b=6 + 4 = 10, b=5

    step 4) write the chemical equation using the variable values

                C3H8 + 5O2 ---> 3CO2  + 4 H2O



    step 5) count the number of atoms on both sides

                       carbon atoms  = 3
                      hydrogen atoms = 8
                      oxygen atoms = 10 





    step 6) we conclude that the equation is said to be balanced. 




    ASSIGNMENT ON BALANCING CHEMICAL EQUATIONS:

    1) Reaction between Iron oxide and carbon to get Iron and carbon dioxide


    2) reaction between hydrogen and oxygen to get water


    3) reaction between acetic acid and ethyl alcohol to get ethyl acetate and water

    4) when sulphuric acid reacts with calcium carbonate to get calcium sulphate along with H2CO3

    5) combustion of methane to get carbon dioxide and water

    6) reaction between copper oxide and sulphuric acid to get copper sulphate and hydrogen

    7) reaction between nitrogen and oxygen

    8) reaction between ammonia and oxygen

    9) reaction between nitrogen and hydrogen

    10) when ammonia reacts with hydro chloric acid to get ammonium chloride

    11) when sodium reacts with water to get sodium hydrogen and hydrogen

    12) when calcium reacts with hydro chloric acid to get calcium chloride and hydrogen