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Adaptations that Reduce Water Loss 01:57

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Though evaporation from plant leaves drives transpiration, it also results in loss of water. Because water is critical for photosynthetic reactions and other cellular processes, evolutionary pressures on plants in different environments have driven the acquisition of adaptations that reduce water loss.

In land plants, the uppermost cell layer of a plant leaf, called the epidermis, is coated with a waxy substance called the cuticle. This hydrophobic layer is composed of the polymer cutin and...

Electrical Energy 01:10

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Using electric appliances for a longer period of time consumes more electrical energy and results in a higher electric bill. The energy produced by the transfer of electrons from one point to another is known as electrical energy. If power is delivered at a constant rate, the electrical energy can be defined as the product of power used by the device for a period of time. The energy unit on electric bills is the kilowatt-hour, where one kilowatt-hour is equivalent to 3.6 × 106 joules.

Power and Energy 01:12

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The power and energy delivered to an element are subjects of great significance in the field of electrical engineering. It is a well-known fact that a 100-watt light bulb emits more light than a 60-watt one. Therefore, power and energy calculations play a crucial role in the analysis of electrical circuits.
Power, defined as the time rate of expending or absorbing energy, is quantified in units called watts (W). The relation between power and energy is mathematically given as

where "p"...

Handwashing I: Introduction and Types of Equipment 01:18

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Handwashing is hand hygiene with plain or antimicrobial soap and water to physically remove dirt, organic material, and microorganisms. However, it may not kill all microorganisms. The handwashing procedure requires a hand wash basin, liquid soap, paper towels, a domestic waste bin, and disposable nail cleaner as optional equipment.
Hand wash basins in clinical areas should have faucets that can be turned on and off without using the hands; that is, they should be non-touch or lever-operated....

Energy Basics 02:27

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Chemical reactions, such as those that occur when you light a match, involve changes in energy as well as matter.

Chemical changes and their accompanying changes in energy are important parts of everyday life. The macronutrients in food undergo metabolic reactions that provide the energy to keep bodies functioning. A variety of fuels (gasoline, natural gas, coal) is burned to produce energy for transportation, heating, and the generation of electricity. Industrial chemical reactions use...

Energy 00:58

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The universe is composed of matter in different forms, and all forms of matter contain energy.  The different forms of energy on Earth originate from the Sun—the ultimate energy source. For instance, plants capture light energy from the Sun, and through the process of photosynthesis, convert it into chemical energy. This stored energy from plants can be harnessed in many ways. For example, eating plant products as food provides energy for our body to function, and burning wood or...