B1.3 Nutrition and Food tests - Food and energy

Question 1

Energy content from food

Answer 1

Different foods have different energy contents, some act as quick sources of energy and others act as long-term stores of energy, such as fat

Question 2

Balancing energy

Answer 2

The energy content of food eaten must be balanced with energy needs since excess energy will be stored as fat by the body, leading to obesity

Question 3

Energy and food content requirements

Answer 3

Vary between individuals and depend on factors such as age, gender and activity levels

Question 4

Calorimeter

Answer 4

An instrument used to measure changes in thermal energy

Question 5

Burning food

Answer 5

Can be used to demonstrate the energy content of different food items

Question 6

Mounted needle

Answer 6

A needle mounted in a wooden or metal handle that is used to impale a food source and hold it over a Bunsen burner

Question 7

Thermometer

Answer 7

Instrument used to measure temperature

Question 8

Bunsen burner

Answer 8

Used safely to heat food products until they set alight, after which the food product is suspended below a boiling tube containing water and a thermometer

Question 9

Boiling tube

Answer 9

Holds a set volume of water and a thermometer to act as a calorimeter

Question 10

Clamp, boss and clamp stand

Answer 10

Keeps the boiling tube and water suspended at an appropriate height and angle

Question 11

Electronic balance

Answer 11

A piece of equipment used to measure the mass of each food source

Question 12

Dependent variable

Answer 12

The variable that is measured, in this case it is the energy content released from food or the change in temperature that results from burning food

Question 13

Independent variable

Answer 13

The variable that is changed, in this case it is the type of food source that is burned

Question 14

Control variables

Answer 14

Variables that are kept the same in an experiment such as the volume of water in the boiling tube, size or quantity of food sample used, distance of burning food source from boiling tube

Question 15

Acclimatisation

Answer 15

It is important that the boiling tube with water is allowed to return to room temperature or a fresh water sample can be used between tests

Question 16

Energy and temperature

Answer 16

The energy content of food can be determined by burning a food sample and immediately suspending it under a boiling tube of water with a thermometer in it, the temperature change suggests the energy content

Question 17

Burning food process

Answer 17

Light a sample of food using a Bunsen burner, move the burning food sample away from the Bunsen burner and place it under a calorimeter, measure the temperature change that results from the burning food

Question 18

Energy released from food equation

Answer 18

Energy released from food per gram = (mass of water x temperature increase x 4.2)/mass of food sample

Question 19

Units for energy, mass, temperature

Answer 19

Energy is measured in Joules, mass for this experiment is measured in (kilo)grams, temperature is measured in degrees Celsius

Question 20

One gram

Answer 20

The mass of one cm^3 of water

Question 21

Specific heat capacity

Answer 21

The energy required to raise a unit mass of a substance by one degree Celsius, for water this value is 4.2 Joules per gram per degree Celsius