90˚ angle

Figure 1 presents a case when sunlight shines on Earth at a lower angle (Sun closer to the horizon), the energy of the sunlight is spread over a larger area, and is therefore weaker than if the Sun is higher overhead and the energy is concentrated on a smaller area.

winter solstice

Poleward of 23.5 degrees N there is never a day when the Sun is directly overhead. Poleward of the Tropic of Cancer you will always have to look south to see the Sun.

Nothing is more important to us on Earth than the Sun. Without the Sun’s heat and light, the Earth would be a lifeless ball of ice-coated rock. The Sun warms our seas, stirs our atmosphere, generates our weather patterns, and gives energy to the growing green plants that provide the food and oxygen for life on Earth.

Solar radiation that is reflected back into space by Earth’s surface or atmosphere does not add heat to the Earth system. Absorbed radiation is transformed into heat.

Heat is the motion of particles (or the propagation of infrared radiation). In a gas or liquid, the motion is not a vibration because that implies a periodic motion, which requires a restoring force.

Chlorophyll is what absorbs the sun’s energy and turns it into chemical energy. Not all the light energy from the sun is absorbed. Sunlight has many different colors in it. Chlorophyll usually absorbs red and blue light from the sun and reflects green light.

For solar applications that use mirrors, thin coatings of silver, aluminum and other metals serve as good reflectors of light.

Black – the color that absorbs all visible wavelengths of light – attracts the most heat, followed by violet, indigo, blue, green, yellow, orange and red, in descending order.

Black is the ultimate heat absorber. It absorbs all light on the visual spectrum, creating a void of light. As a result of absorbing all light wavelengths, black is the hottest possible color. White is the opposite.

Anything that reflects a color will look that color. White, gray, and black are not colors, though: white reflects all colors, black absorbs all colors, and gray reflects some and absorbs some of all colors. Any light that is absorbed, of any color, becomes heat.

Black clothing absorbs more light and that, in turn, gets converted to more heat. A black shirt, on the other hand, absorbs all of the wavelengths of light, reflecting none of them back to our eyes. As a black shirt absorbs all of the light that hits it, it converts that light into other forms of energy, usually heat.

Different surfaces You can see that dull surfaces are good absorbers and emitters of infrared radiation. Shiny surfaces are poor absorbers and emitters (but they are good reflectors of infrared radiation).

Matte black painted metal will both absorb more heat and radiate more heat.

Styrofoam is made mostly of air, meaning it is a poor conductor of heat, but an excellent convector. It traps the air in small pockets, blocking the flow of heat energy. This reduces both conduction and convection and makes Styrofoam a good insulator.

Which one heats up fastest? The cans are identical except for their surfaces. We’ve probably all noticed, by leaving black objects out in the sun, that they heat up fastest. The black can absorbs radiation more efficiently than does the shiny can, which reflects most of the radiation away.

Answer: The factor or condition that is necessary for heat transfer to occur is that two object ‘must have different temperature’. Heat always flow or move from the hotter object to the cooler one. Heat Transfer can occur in three ways: Conduction, Convection, and Radiation.

Glass wool

Answer. THE FOOD COLORING IS TRANSFER OF HEAT.

Transfers of matter into and out of the physical environment occur at every level—for example, when molecules from food react with oxygen captured from the environment, the carbon dioxide and water thus produced are transferred back to the environment, and ultimately so are waste products, such as fecal material.

Convection occurs when particles with a lot of heat energy in a liquid or gas move and take the place of particles with less heat energy. Heat energy is transferred from hot places to cooler places by convection. Liquids and gases expand when they are heated. The denser cold liquid or gas falls into the warm areas.

The food coloring has a slightly higher specific gravity, or relative density, than water, so before it has time to diffuse, it tends to sink in the water. When the water is cold, and the diffusion rate is slower, more of the food coloring stays together in a plume falling to the bottom of the container.

Answer: -the food coloring drops on the water, as it drops, it spreads throughout the bottle smoothly. – when it spreads, it’s starting to loss its color. – when dropped on the water, it spreads in any direction.

The food coloring will mix the fastest in the hot water because the molecules are moving fast due to their increased thermal energy. These fast-moving molecules are pushing the molecules of food coloring around as they move, causing the food coloring to spread faster.

Does food coloring dissolve in water? Yes. The solute (food coloring) is dissolved in the solvent (water) when the molecules of the solute are so thoroughly intermixed within the molecules of the solvent that they do not settle out or separate. This demonstration showed that food coloring can dissolve in water.

Cooling a substance causes molecules to slow down and get slightly closer together, occupying a smaller volume that results in an increase in density. Hot water is less dense and will float on room-temperature water. Cold water is more dense and will sink in room-temperature water.

In cold water, the food coloring diffuses (spreads out) through the water slowly. The hot water causes the food coloring to diffuse faster. At higher temperatures, particles move faster. This faster movement allows diffusion to occur more quickly.