Energy and Water

Why do the interactions between solar energy and water have a major influence on weather? Only 30% of Earth’s surface is land, and clouds cover much of this land. Therefore most incoming solar radiation that penetrates the atmosphere strikes water. Solar energy drives our weather systems including temperature. The relative constant temperature of water helps to stabilize global temperatures, climates and drive weather systems such as hurricanes (latent heat of vaporization feeds such storms).

Define Specific Heat Capacity. The amount of heat that is required to raise the temperature of 1g of substance 1°C. Heat put in or out of a substance Mass of a substance (grams) Specific heat capacity Change in temperature

Explain why the type of interaction that occurs between solar radiation and water depends on the state of the water Depending on the state of the water (solid, liquid, gas) the amount of incoming solar radiation reflected will vary. Ice reflects 50%, snow reflects up to 90%, while water only 7%. ALSO: depending on the state of water, heat energy is either being absorbed (liquid to gas), or taken away from the water (liquid to solid).

Explain how the specific heat capacity of water influences the temperature of a large lake. Water needs 4.18 J/g°C of heat to raise 1°C. It has a high specific heat capacity, meaning it takes more heat to raise 1°C. Rivers and lakes have a relatively constant temperature because of its large heat capacity (it needs more heat than other substances to warm up). OR The large heat capacity helps to moderate its temperature because the temperature change (delta T) is relatively small when water absorbs a large amount of energy.

Which substance in nature will rise in temperature the quickest if each substance was exposed to the amount of solar radiation? SubstanceSpecific Heat Capacity (J/g°C) Pure water4.18 Sea water3.89 Dry air1.00 Wet mud2.51 Brick0.84 Granite0.79 limestone0.92 Limestone as it only takes 0.92 Joules of energy to increase it by 1°C.

Which liquid in nature will rise in temperature the quickest if each liquid is exposed to the same amount of solar radiation? LiquidSpecific Heat Capacity (J/g°C) Water4.18 Methanol2.55 Ethanol2.46 Hexane2.26 Toluene1.80 Toluene as it required the least amount of heat energy.

Why does pure water have a larger heat capacity then limestone? Pure water is transparent, liquid and has motion. Most solar energy that strikes water will transmit through the liquid, requiring more energy to heat up this substance. Molecules in water are also spread apart. Limestone in a solid, when solar energy hits this substance it is able to reach more molecules/atoms as they are closer together, and energize them. Thus, it takes lesser energy to heat up limstone.

What is Heat of Vaporization? The amount of energy that is required to convert 1g of a substance from a liquid to a gas. (heat is absorbed to create the vapor) If gas condenses back into a liquid, the same amount of energy is released ---this is latent heat!!!

Why does the latent heat of vaporization interfere with the ability of water to rise in temperature? When water absorbs solar energy, some of the energy is used to rise the temperature of the water – remember water has a large heat capacity and therefore needs a lot of thermal energy to raise its temperature. BUT not all the energy that strikes water is used to rise temperature, some is used to evaporate water!

Why will summers in Winnipeg, Manitoba experience higher average temperatures than Halifax, Nova Scotia? 1.Location: Winnipeg is inland and Halifax is coastal. 2.Thermal Properties of water vs. land (Specific Heat Capacities) 1.Water is liquid, transparent, has motion, molecules are further apart. As a result, its takes more energy to warm the waters (thus a higher specific heat capacity). Land is more dense, atoms/molecules are closer together enabling the solar energy that reaches land to transfer between atoms/molecules easily. Thus allowing the land to warm up with less solar energy.

3. Heat of Vaporization –When water is heated, some of the energy absorbed leads to the conversion of liquid into gas. –Latent Heat over land is very limited. These factors together, contribute to inland areas feelings warmer summers than coastal. Inland will receive higher maximum daily temperatures in the summer than coastal. Coastal areas, due to the factors mentioned, will not experience such highs as these factors help to moderate the oceans temperature which directly influence air temperatures nearby.

Define Heat of Fusion The amount of heat required to melt 1.0g of a solid into a liquid. Reversly, it is the amount of energy that is released when 1g of a liquid freezes or becomes solid. The amount of heat energy required to melt 1g of ice to water is 333J/g

Does ice contain heat? YES! Energy is needed in order to change the states of water!Whether it be liquid to gas, gas to liquid, solid to liquid, liquid to solid! In order for a liquid to freeze, a certain amount of energy/heat has to be released from the ice. (333J/g)