Animals and plants need these salts (which include calcium, magnesium, potassium and the sodium you might be familiar with as table salt) to grow, develop and stay healthy. It usually contains dissolved mineral salts. Most water in the ground is not pure water. In this activity you will see for yourself how you can make water move with osmosis! A process called osmosis helps the water move from the soil into the plant roots-and then into the plant's cells. As this damage builds, you speed up the aging of your skin and increase your risk for all types of skin cancer.Įven on cloudy days, ultraviolet radiation can pass through clouds and cause a sunburn if you remain outdoors long enough.Have you ever wondered how plants "drink" water from the soil? Water uptake in plants is quite complicated. Every time you tan, you damage your skin. This includes radiation from artificial sources, such as tanning beds and sun lamps. UVB rays are the primary cause of sunburn and are blocked by window glass.UVA rays can prematurely age your skin, causing wrinkles and age spots, and can pass through window glass.In addition to causing skin cancer, here's what each of these rays do: Overexposure to either can lead to skin cancer. The warmth of the sun does not lead to a sunburn.įrom the American Academy of Dermatology, sunlight consists of two types of harmful rays that reach the earth - ultraviolet A (UVA) rays and ultraviolet B (UVB) rays. It is not the heat you feel but ultraviolet radiation from the sun that causes sunburns that lead to skin cancer. Convection currents are responsible for many weather patterns in the troposphere. These movements of air masses can be small in a certain region, such as local cumulus clouds, or large cycles in the troposphere, covering large sections of the earth. As it rises, the bubble cools with the heat contained in the bubble moving into the atmosphere.Īs the hot air mass rises, the air is replaced by the surrounding cooler, more dense air, what we feel as wind. This bubble of air rises into the atmosphere. As the rock's temperature rises due to conduction, heat energy is released into the atmosphere, forming a bubble of air which is warmer than the surrounding air. The sun's radiation strikes the ground, thus warming the rocks. This type of heating is most commonly seen in the kitchen with a boiling liquid.Īir in the atmosphere acts as a fluid. ConvectionĬonvection is the transfer of heat energy in a fluid. This is called conduction and is a very effective method of heat transfer in metals. Also, when objects are welded together, the metal becomes hot (the orange-red glow) by the transfer of heat from an arc. This is due to transfer of heat energy from molecule to molecule or from atom to atom. Learning Lesson: Melts in your bag, not in your hand Conduction However, they also radiate their energy faster than lighter colored objects. Dark colored objects, such as asphalt, absorb radiant energy faster than light colored objects. Most of the solar radiation is absorbed by the atmosphere and much of what reaches the earth's surface is radiated back into the atmosphere to become heat energy. It is infrared radiation that produce the warm feeling on our bodies. Waves from the sun which we cannot see are infrared, which have lower frequencies than red, and ultraviolet, which have higher frequencies than violet light. When the eye views all these different colors at the same time, it is interpreted as white. Our brains interpret these different frequencies into colors, including red, orange, yellow, green, blue, indigo, and violet. In electromagnetic radiation, its frequency is the number of electromagnetic waves moving past a point each second. The frequency is the number of instances that a repeated event occurs, over a set time. Light is made of waves of different frequencies. Only a small portion comes as visible light. Most of the electromagnetic radiation that comes to the earth from the sun is invisible. Radiation is the transfer of heat energy through space by electromagnetic radiation. Heat lamps, that keep food warm, work in the same way. Although you are surrounded by air, the air has nothing to do with this transfer of heat. The side of your body nearest the fire warms, while your other side remains unaffected by the heat. If you have stood in front of a fireplace or near a campfire, you have felt the heat transfer known as radiation. There are three ways heat is transferred into and through the atmosphere: Since this energy warms the earth's surface and atmosphere, some of it is or becomes heat energy. Energy from the sun is transferred through space and through the earth's atmosphere to the earth's surface. The heat source for our planet is the sun.
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