Energy in Food Lab

Glucose has energy stored in its chemical bonds that can be used by other organisms. This stored energy is released when bonds are broken (such as in cellular respiration).

Cellular Respiration Chemical process Chemical energy of “food” molecules is released and partially captured as ATP

Carbohydrates, fats, proteins, nucleic acids can all be used as fuels in cellular respiration. (Glucose is the one most commonly used in examples)

Why do marathon runners eat carbohydrates and proteins the night before a big race? Good source of energy/fuel for the body

What is Energy? The ability to do work. Potential energy Stored energy Kinetic energy Energy in motion

Potential energy in food All foods contain energy The amount of potential energy in food varies depending on the type of food. However, not all the energy stored in food is available to do work.

When we eat food our body converts the stored energy…called CALORIES…to chemical energyallowing us to do work.

Calorie The amount of heat (energy) required to raise the temperature of 1 gram (g) of water 1 degree Celsius (C) . Density of water is 1 gram per milliliter (1g/ml), therefore 1 g of water is equal to 1 ml of water.

Caloric Values of Food We call the caloric values of food Calories (notice the capital letter), which actually is kilocalories. There are 1000 calories in a kilocalorie So, in reality a food that has 38 Calories has 38,000 calories. Calories are a way to measure the energy you get from the food you eat.

A peanut has stored energy that can be used to heat a container of water. In this lab, you will indirectly measure the amount of Calories in a couple of food items using a calorimeter Calor=Latin for heat A calorimeter is a devise that measures the heat generated in a chemical reaction.

We will use a homemade calorimeter. The food item will be ignited, the homemade calorimeter will trap the heat of the burning food, and the water above will absorb the heat. This will cause the temperature (T) of the water to increase/ By measuring the change in temperature (∆T) of a known volume of water you will be able to calculate the amount of energy in the food tested.

Lab Objective You will measure the amount of energy available for use from three types of nuts, a plant product. This process of measuring energy stored in food is known as calorimetry.

Materials Soda can with two openings cut into the side of the soft drink can

A large size paper clip bent to attach nut on one end and bent so it will hang from the soda can on the other end.

Graduated cylinder to measure 100 g (100 ml) of water. An uncut empty soda can Thermometer Electronic balance

Procedures Measuring using a graduated cylinder

Measuring using an electronic balance https://www.youtube.com/watch?v=FTajx52q2II Demo on how to tare the scale and mass your food.

Lab set up

Safety Make sure the cans are sitting on flat, nonflammable surface No backpacks, papers, personal items near lab set up Matches go in beaker…not the trash…until we know for sure they are out. Hair tied back No loose clothing Pay attention to flamesl No horseplay!