Class 9 Science Notes CBSE Class 9 Science Notes Chapter 1 Matter In Our Surroundings:
CBSE Class 9 Science Notes Chapter 1 Matter In Our Surroundings:
NOTES
• Matter is anything that has mass and occupies space
• Matter exists in three physical states: solid, liquid, and gas.
• The kinetic theory of matter states that matter is made up of tiny particles that are in constant motion.
• The intermolecular forces between particles determine the physical state of matter.
• The melting point and boiling point of a substance are the temperatures at which it changes its physical state from solid to liquid and liquid to gas, respectively.
• The change of state from solid to liquid is called melting, while the change of state from liquid to gas is called vaporization.
• Sublimation is the process in which a solid directly changes to a gas without going through the liquid state.
• Evaporation is a type of vaporization that occurs only at the surface of a liquid.
• The rate of evaporation is affected by factors such as temperature, surface area, and humidity.
• The atmospheric pressure decreases with increasing altitude, which affects the boiling point of liquids.
• The process of cooling can cause condensation, which is the change of state from gas to liquid.
• The physical properties of matter include color, odor, density, boiling point, melting point, and solubility.
• The states of matter can be changed by applying pressure. For example, applying pressure to a gas can cause it to condense into a liquid.
• The triple point of a substance is the temperature and pressure at which all three states of matter (solid, liquid, and gas) exist in equilibrium.
• The critical temperature and pressure of a substance are the minimum temperature and pressure at which a gas can be liquefied, regardless of the pressure applied.
• The water cycle is the continuous movement of water between the Earth's surface, the atmosphere, and bodies of water.
• Humidity is the amount of water vapor present in the air. The amount of water vapor that air can hold increases with temperature.
• Relative humidity is the ratio of the amount of water vapor present in the air to the amount that the air can hold at a particular temperature.
• The dew point is the temperature at which the air becomes saturated with water vapor, causing dew or frost to form.
• The ozone layer is a layer of ozone gas in the Earth's atmosphere that protects the planet from harmful ultraviolet radiation from the sun.
• The physical properties of matter include color, odor, density, boiling point, melting point, and solubility.
• The states of matter can be changed by applying pressure. For example, applying pressure to a gas can cause it to condense into a liquid.
• The triple point of a substance is the temperature and pressure at which all three states of matter (solid, liquid, and gas) exist in equilibrium.
• The critical temperature and pressure of a substance are the minimum temperature and pressure at which a gas can be liquefied, regardless of the pressure applied.
• The water cycle is the continuous movement of water between the Earth's surface, the atmosphere, and bodies of water.
• Humidity is the amount of water vapor present in the air. The amount of water vapor that air can hold increases with temperature.
• Relative humidity is the ratio of the amount of water vapor present in the air to the amount that the air can hold at a particular temperature.
• The dew point is the temperature at which the air becomes saturated with water vapor, causing dew or frost to form.
• The ozone layer is a layer of ozone gas in the Earth's atmosphere that protects the planet from harmful ultraviolet radiation from the sun.
Comments