Grade 7
  1. Introduction to Physics  1.1. Definition and scope of physics  1.2. Importance of Physics in Daily Life and Technology  1.3. Scientific method and its applications in physics  1.4. Measurement and Experiments in Physics  1.5. Branches of Physics and their Applications  1.6. Relation of physics with other sciences
  2. Measurement and units  2.1. Fundamental and derived quantities  2.2. SI units and unit conversions  2.3. Length measuring instruments and tools used  2.4. Measuring the difference between mass and weight  2.5. Measuring time with accuracy  2.6. Measuring the Volume of Regular and Irregular Objects  2.7. Measuring Temperature and Temperature Scales  2.8. Accuracy, Precision, and Significant Figures  2.9. Errors in Measurement and How to Reduce Them  2.10. Estimates and approximations in scientific calculations  2.11. Standard form and order of magnitude
  3. Speed and Force  3.1. Introduction to motion and rest  3.2. Types of motion - uniform and non-uniform  3.3. Scalars and vectors in motion  3.4. Speed, Velocity, and Acceleration  3.5. Distance-time and velocity-time graphs  3.6. Newton's first law of motion (law of inertia)  3.7. Newton's second law of motion (force and acceleration)  3.8. newton's third law of motion  3.9. Types of forces - contact and non-contact forces  3.10. Effect of forces on motion  3.11. Friction – types, effects and applications  3.12. Gravity, free fall and gravitational acceleration  3.13. Circular motion and centripetal force  3.14. Application of Newton's laws in real life
  4. Energy, Work and Power  4.1. Definition and forms of energy  4.2. Potential and Kinetic Energy  4.3. Law of conservation of energy  4.4. Energy transformations in everyday life  4.5. Work done by force and its calculation  4.6. Power - Definition and Calculation  4.7. Simple Machines and Mechanical Advantage  4.8. Efficiency and energy losses of machines  4.9. Renewable and non-renewable energy sources
  5. Heat and temperature  5.1. Difference Between Heat and Temperature  5.2. Thermometer and temperature scale (Celsius, Kelvin, Fahrenheit)  5.3. Expansion and contraction of solids, liquids and gases  5.4. Heat transfer methods – conduction, convection and radiation  5.5. good and bad conductors of heat  5.6. Applications of heat transfer in daily life  5.7. Specific heat capacity and its applications  5.8. Latent heat and change of state  5.9. Thermal equilibrium and heat exchange  5.10. effect of heat on matter
  6. Lighting and Optics  6.1. Nature and properties of light  6.2. Reflection of light and laws of reflection  6.3. Image formation by plane and curved mirrors  6.4. Refraction of light and the laws of refraction  6.5. Lenses – convex and concave, image formation  6.6. Optical instruments – microscope, telescope, camera  6.7. Dispersion of light and formation of spectrum  6.8. Human eye, vision defects and their correction  6.9. Applications of optics in daily life  6.10. Total internal reflection and its applications
  7. Sound and waves  7.1. Nature and properties of waves  7.2. Production and propagation of sound  7.3. Characteristics of sound waves – frequency, amplitude, wavelength  7.4. Speed of sound in different mediums  7.5. Reflection of sound – echo and reverberation  7.6. Ultrasound and its applications  7.7. Doppler effect in sound waves  7.8. Noise pollution and its effects  7.9. Applications of sound in medicine and industry
  8. Electricity and Magnetism  8.1. Electric charge and static electricity  8.2. Electrical conductors and insulators  8.3. Electric current, voltage and resistance  8.4. Ohm's law and its applications  8.5. Electrical Circuits - Series and Parallel Circuits  8.6. Electric power and energy consumption  8.7. Safety precautions in the use of electricity  8.8. Properties of magnets and magnetic fields  8.9. Electromagnets - How They Work and Their Uses  8.10. Relation between electricity and magnetism (electromagnetic induction)  8.11. Applications of electromagnetism in technology  8.12. Earth's magnetic field and its effects
  9. Matter and its properties  9.1. Classification of matter- solid, liquid and gas  9.2. Properties of different states of matter  9.3. Kinetic theory of matter  9.4. Changes in the state of matter and their causes  9.5. Expansion and contraction of substances  9.6. Density and its calculation  9.7. Pressure in solids, liquids and gases  9.8. Atmospheric pressure and its effects  9.9. Applications of pressure in daily life  9.10. Buoyancy and Archimedes' principle
  10. Space Science and Solar System  10.1. Introduction to Astronomy  10.2. Solar System - Planets and their Characteristics  10.3. Sun - structure and energy production  10.4. Moon - phases and its effect on Earth  10.5. Rotation and revolution of the earth  10.6. Solar and lunar eclipses  10.7. Gravity in space and its role in orbits  10.8. Artificial satellites and their uses  10.9. Space exploration and modern discoveries  10.10. Asteroids, comets and meteors  10.11. Life beyond Earth - Possibilities and Theories
  11. Environmental Physics  11.1. Impact of physics on environmental science  11.2. Renewable and non-renewable energy sources  11.3. Energy conservation and efficiency  11.4. Climate change and its effects on Earth  11.5. Air, water and soil pollution – causes and effects  11.6. Greenhouse effect and global warming  11.7. Sustainable development and environmental protection  11.8. Role of Physics in Weather and Climate Studies

Grade 7 → Sound and waves ↓


Applications of sound in medicine and industry


Sound is a type of energy that travels through air and other materials. It is produced when an object vibrates. These vibrations create sound waves that travel through mediums such as air, water, and solid surfaces. Sound is an important aspect of everyday life, not only for communication but also in various practical applications in medicine and industry. Let us learn about these in detail.

Sound in medicine

The use of sound in medicine is an interesting topic. Sound waves are used in many different ways to help diagnose and treat medical conditions. Here are some of the major applications:

1. Ultrasound imaging

Ultrasound imaging is one of the most common medical applications of sound. It uses high-frequency sound waves that are beyond the range of human hearing, known as ultrasound. These waves travel through the body and reflect off various structures. The reflected waves are captured by a computer and converted into an image.

Frequency for ultrasound imaging: 2 MHz to 18 MHz

Doctors use ultrasound to see babies in the womb (pregnancy ultrasound), examine organs, and check for conditions such as heart problems. Below is a simplified visual representation of how an ultrasound machine works:

Ultrasound Transducer Transducer computer screen

2. Lithotripsy

Lithotripsy is a medical procedure that uses sound waves to break up kidney stones. High-energy shock waves are focused on the stones, causing them to break into smaller pieces, which can then be easily passed out through urine.

Example: A person suffering from kidney stones can undergo a lithotripsy session. The focused shock waves will break up the stones without any invasive surgery, making it a less painful procedure.

3. Hearing aids and cochlear implants

Hearing aids amplify sound for people with hearing loss, while cochlear implants are electronic devices that help people with severe hearing loss perceive sound. Both use technology that processes sound waves to improve hearing ability.

4. Sound therapy

Sound therapy uses different sounds and frequencies to treat and manage mental health problems, stress and relaxation. It relies on the calming and restorative effects of certain sound vibrations to improve psychological well-being.

Sound in the industry

In industry, sound waves are used in various ways to improve efficiency, safety and productivity. Let us discuss some important applications:

1. Acoustic testing and non-destructive testing (NDT)

Acoustic testing is used to identify problems in materials or systems using sound waves. Non-destructive testing (NDT) involves methods that do not damage the object being tested. Ultrasonic testing, a form of NDT, uses high-frequency sound waves to detect defects in materials.

Speed of sound in steel: ~6000 m/s

Example: Inspecting a bridge for cracks or defects may involve sending sound waves through its structure. Changes in the wave pattern help engineers detect structural problems.

2. Sonar technology

Sonar (sound navigation and ranging) uses sound waves to detect underwater objects. It sends out sound waves and listens for their echo, which is analysed to determine the distance, size and speed of objects such as submarines, ships or schools of fish.

Sonar waveform Reflected echo

3. Acoustic levitation

In acoustic levitation, high-intensity sound waves are used to suspend small particles, droplets or even lightweight materials in the air, creating a pressure point that balances gravity.

Acoustic levitation is used in the handling of sensitive materials, such as moving delicate particles in laboratories, where contact with surfaces can cause contamination or reactions.

4. Sound-based cleaning

Sound waves can be used for cleaning. Ultrasonic cleaners use high-frequency sound waves to remove dirt from items such as jewelry, components, and medical equipment.

Example: An ultrasonic cleaner vibrates a liquid solution at high speed, removing dirt from jewelry or surgical instruments. It is effective without using harsh chemicals.

Additional concepts in sound

How does sound travel?

Sound travels in waves and needs a medium such as air, water or a solid to travel through. The speed of sound depends on the medium:

  • In air: about 340 m/s
  • In water: about 1500 m/s
  • In steel: about 6000 m/s

Frequency and pitch

The frequency of a sound wave determines its pitch. Frequency is measured in Hertz (Hz), and it refers to the number of times the wave oscillates per second.

Pitch = Frequency

Higher frequencies are perceived as higher tones, and lower frequencies as lower tones. This is why the flute sounds "higher" than the tuba, which produces lower frequency sound waves.

Amplitude and loudness

The amplitude of a sound wave determines its loudness. Amplitude is a measure of the height of the wave and is related to how much energy the sound wave carries. The higher the amplitude, the louder the sound.

Dimensions

Conclusion

Sound plays an indispensable role in everyday life and in professional fields such as medicine and industry. From diagnosing diseases through ultrasound to ensuring the integrity of materials using acoustic testing, the applications of sound waves are varied and impressive. Understanding these applications helps us understand the importance of sound beyond just communication and the enjoyment of music.

As technology advances, the use of sound in these areas is likely to expand, leading to even more innovative solutions and improvements in both medical and industrial contexts.


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