Experiment 2.32 Energy Content of Food

Recall how to carry out a simple experiment to determine the energy content in a food sample

Equipments:

Thermometer

Boiling Tube (filled with 20cm^3 of water)

Crucible --> measured mass of food sample 

Record initial temperature of water in Celsius, for example, 20C.

The food source is ignited and there is a heat transfer from the food source to the water. When the food is completely combusted, we then record the final temperature of the water, for example 30C. 

1 cm^3 of water has a mass of 1 g. 

1 cm ^3 of water, to raise its temperature by one degree takes 4.2 J. 

Calculation:

(mass of water (g) x temperature rise (C ) x 4.2)

Energy released from food per gram = ------------------------------------------------

mass of food sample (g)

= [20 x (30-20) x 4.2] / 10

= 84J / g

Cloning

1. An egg cell was removed from the ovary of an adult sheep B The egg cell's nucleus is then removed. 
2. Nucleus from the organ cell, for example udder cell, of adult sheep A is the taken out and inserted into the empty egg cell. 
3. The fused cell has complete set of chromosome and began to develop normally (in the lab) using genetic information from the donated DNA. 
4. Before the dividing cells specialize, the embryo is implanted into the uterus of a surrogate mother sheep C. The offspring is genetically identical to sheep A.