Energy Value In Food

Energy value in food samples..... . EXPERIMENT 6.1

AIM • To determine the energy value in food samples.

PROBLEM STATEMENT • What is the energy value of different food samples?

HYPOTHESIS • The energy values of different food samples are different.

VARIABLES • Manipulated variable: food samples • Constant variable : volume of water • Responding variable: energy value of food samples

MATERIALS • Distilled water, food sample (groundnut, green bean, flour) and plasticine.

APPARATUS • A thermometer, a boiling tube, a retort stand and clamp, a pin, an electronic balance, wind shield and a Bunsen burner

TECHNIQUE • Calorimetry- measuring of the amount of heat released in its combustion.

PROCEDURE • 1. 10ml of water (mass=10 g) is poured into a boiling tube and the boiling tube is clamped to the retort stand in an upright position. • 2. a small piece of food is weighed and recorded. • 3. the initial temperature of the water in the boiling tube is recorded.

• 4. the food is fixed at the end of the mounted pin. • 5. the food is burned using the Bunsen burner. • 6. as soon as the food burns, hold it about 1cm below the boiling tube.

• 7. the water in the boiling tube is stirred with a thermometer and the temperature rise is recorded when the food stops burning. • 8. the boiling tube is emptied and refilled with another 10ml of water.

• 9. repeat steps 1 – 8 using a different food sample each time. • 10. the energy value of food is calculated with the following formula: • Energy value= mass of water (g) x temperature rise (oC) x 4.2J/goC mass of food (g) •

Types of foods measurement

groundnut

Mass/g

flour

0.33

green bean 0.1

Initial temperature/oC

29

29

29

Final temperature/oC

44

31

45

Change in temperature/oC

15

2

16

Energy value (J/g)

1909

840

134.4

5

CONCLUSION • Experimental results show that groundnut, green bean and flour have different food values. • Decision: hypothesis is accepted