Energy Lab Assignment

Part A

3 . Black can heats faster than the silver one . The reason is that dark colored objects absorb energy better than light ones . Can painted flat black would absorb most of the energy that falls on it , while silver can acts as a reflector

4 . Black can looses its heat faster because of the Stefan-Boltzmann 's Principle . This principle says than the rate of the emitted heat is proportional to the object temperature in fourth power . Therefore , the body with higher temperature emits a lot more energy than the body with

br lower temperature . Therefore , the black can cools off faster than the silver can

5 . Incoming light wave of the heat lamp creates electric field directed at the cans . Due to the influence of this electric field , kinetic energy of the electrons in the can surface increases , thus electrons move fasters causing vibrations , giving up kinetic energy into heat . The air inside the can is also heated due to the interaction with the atoms of the can 's body . The atoms of the air in their turn interact with the thermometer

Part . B

11 . Beaker and thermometers with the soil got hotter , while beaker and thermometers with water got cooler because specific heat of water is 5 times as larger as specific heat of soil . Soil can not hold as much energy as water and radiates it away

12 . Beaker with soil cooled off faster that beaker with water , due to Stefan-Bolzman Principle . Beaker with soil had higher temperature therefore , according to the above mentioned principle it emitted more radiation and lost heat faster

13 . Beaker with water held the absorbed energy better because the special heat of water is 5 times as large as special heat of soil Moreover , since water temperature increases slower , it does not emit as much energy as soil due to Stefan-Boltzmann Principle

Summary questions

If you were asked to design container that would absorb sunlight and store the heat generated so that the heat is released slowly on a cold winter day , what would you choose for materials ? Why

I would select a black container filled with water . Black surface absorbs large fraction of incoming energy that would be stored in water Specific heat of water is rather high , therefore , it can store large amount of energy , without getting hot fast . Since the temperature of water increases slowly , it will hold the energy and release it slower than other materials due to Stefan-Boltzmann principle

Why is it cooler on a sunny day and warmer at night at the beach that it is further away from the beach

Because of the high specific heat , water heats up slower than other materials . Therefore , the temperature of water is always lower than the temperature of soil or sand

On the other hand , due to Stefan-Boltzmann principle water cools off slower because it heats up slower . Therefore , when sand and soil have already emitted most of their energy , temperature of water is higher

Where are possible sources...