Investigating factors which affect heat loss from a beaker of hot water.

Anthony Bashyam

Investigating factors which affect heat loss from a beaker of hot water

Planning

In this investigation I am going to survey the factors that affect heat loss from a beaker filled with 55ml of hot water. This will be done by using a numerous amount of materials.

Factors which affect heat loss from a beaker of hot water:

- Mass of H2O

- Size of beaker

- Temperature Difference

- Material Colour

- Air Pressure

- Relative Humidity

Forms of heat loss:

Radiation

This is the loss of energy, in this case heat energy, through the atmosphere via electromagnetic waves. (This gives it the ability to travel through a vacuum, i.e. the sun shining through space to Earth.) When this energy reaches an object it is absorbed by it. The energy absorbed causes particles in the object to vibrate, and so it heats up. The hotter an object is, the more energy it has and therefore more radiation will occur. Also the larger the surface area of an object, the more energy it will radiate. Dull coloured objects radiate more energy than shiny objects.

Convection

Convection is the expansion of particles when they are heated. When a water is heated, the particles within the substance expand and become less dense that normal.

Due to this decrease in density the particles rise through the substance, and at the surface of the water some of the particles evaporate. As more water evaporates, more and more energy is lost and so the water cools down and when evaporation occurs the object that the substance is evaporating off cools. (This is shown well when you get out the shower and you feel cold because the water is evaporating off of you). When the particles move away from the heat source or are so expanded that the particles are not passing heat from one to another, the particles cool. When they cool they compress back to their original density, which causes them to fall to the bottom of the water. As they are now tightly packed they heat is conducted from one particle to another and they heat, expand, rise, cool and so on as the cycle continues. This cycle is called convection current..

Conduction

Conduction can take place in solids, liquids and gases. When a material is heated the particles nearest to the heat gain kinetic energy. They then start to vibrate faster due to this energy and as they do they touch other particles and transfer the kinetic energy to them. This process is repeated and the energy is transferred through out the object from hot regions to cooler regions. As the water looses heat from the sides of the beaker, conduction will cool the mass of the water. Conduction will also occur through the sides of the beaker and ...