Thursday July 9th, 2015
Review
- Rules and expectations
- Discussed our Pineapple Enzyme, Jello Laser, and Attractive Properties Experiments and what our results were.
- Discussed what we will do in our last two classes!
- Demonstrates the amount of starch and glucose in foods.
- All foods contain chemicals. Some of the most common ones are the nutrients glucose (a sugar), fat, and starch. It's not difficult to detect these nutrient chemicals in food. In this activity, you'll use simple tests to determine their presence in everyday foods.
- The experiment was explained and students gave hypothesis about the results of each tested food sample. Students handed experiment worksheet and glucose and sugar worksheet.
- We used iodine, litmus paper, and brown paper squares to test the starch and glucose content of each of our foods.
- Our classes tested peanut butter, crackers, applesauce, pretzels, potato chips, chocolate sauce, sriracha sauce, pineapple, and watermelon.
- We took 3 samples from each food item and placed one sample in a small cup with litmus paper, rubbed one sample of each on brown paper squares, and the third sample in a cup with iodine.
- Students recorded their results on both worksheets as the class discussed the outcome of each item in each sample.
- Class discussed and documented our conclusion that foods are composed of various chemicals, the most common being sugar, starch, and fat, and calories. Although these chemicals are the most common in foods, it is important that we eat them in moderation as eating an excess of these chemicals may lead to health issues such as diabetes, obesity, and heart disease.
- Demonstrates levels of fat contained in a variety of foods.
- Our last experiment tested the amount of starch and glucose in common foods. We now learn about fat content in food, which will tie into our next experiment; Energy in Foods.
- We discussed earlier that too much of certain chemicals in foods can lead to health issues. Class discussed how too much fat cause what health issues and discussed the FDA's role in accurately labeling the fat content of each food product.
- We used graph paper, a variety of chips, wax paper, and a rolling pit to help determine the fat content of each food item.
- Students completed an experiment worksheet and graph. Class discussed what their hypothesis were and documented what they thought.
- Students crushed the chips on paper and let it sit to see how much oil absorbed into the paper. They placed the oil stained paper on top of the graph paper and recorded their results.
- Students discussed what they though was happening and devised their conclusion. Students concluded that some brands of chips have a great amount of fat in each serving, and some chips do not. The chips with a great amount of fat should be a "sometimes" snack, and the snacks with the least amount of fat can be eaten more moderately. Fats
- Demonstrates foods with high and low energy (calorie).
- Our last two experiments discussed the amounts of the most common chemicals found in foods: starch, fat, and sugar. We now experiment to find how much energy (calories) each of our foods contain. We'll use some of our previously experimented foods, and add some additional foods to test and compare energy content. The experiment is two parts, one of which we will begin in our last class tomorrow and will finish it in time to exhibit our results to our families at the end of class!
- Students handed prediction and experiment worksheets to complete their observations.
- Predictions made about what foods may be high or low calorie (energy), and if calories were good or bad.
- Students made their best guess on what 200 calories of each food item looked like, and used the nutritional labels to determine the calorie content of each food.
- Students learned that a calorie is a unit of energy; it's the amount of energy (heat) taken to raise the current temperature of 1 gram of water, to 1 degree Celsius (1.8 degrees Fahrenheit) higher.
- Each of our previously discussed chemicals contain a certain amount of calories. Students hypothesized how many calories where in each chemical, and discussed as a class the amounts: carbohydrate (starches) and protein both contain 4 calories, both sugar and fat contain 9 calories.
- Students concluded that the number of calories in a food is a measure of how much potential energy that food has.
In part two, we'll use a calorimeter to further test the calorie content and energy in foods by igniting a food sample in the homemade calorimeter. The calorimeter traps the heat of the burning food, and cause the temperature of the water in the calorimeter to increase. By measuring the change in temperature of a known volume of water, students will be able to calculate the amount of energy in the food tested because the heat gained by the water will equal the heat lost by the food item. We'll multiply the number of grams of fat by the number of calories in a gram of that food component to get our calories per gram (serving of . For example, a serving of bananas has an estimated amount of .4 grams of fat, where 3.6 calories are from fat.
We asked earlier if calories were bad or good for us. The recommended range for most school-age kids is 1,600 to 2,500 per day. If you eat more calories than your body needs, the leftover calories are converted to fat. (Remember our lesson from Tuesday when we talked about fat clogging arteries). Your body needs some calories just to operate - to keep your heart beating and your lungs breathing, to grow and develop. be active for at least 1 hour and up to several hours a day. Try to limit watching TV, being on the computer, etc. activities to 1 to 2 hours per day. A person burns only about 1 calorie per minute while watching TV, about the same as sleeping!
Review of Class Lessons
- Discussed the fat, starch and glucose contents of foods; which had the most/ least, which were "sometimes" foods and which foods could be eaten more regularly.
- Discussed our results of each experiment.
Looking Ahead to Tomorrow's Lesson
We'll complete part two of our calorie experiment and use a calorimeter! Discussed how a calorimeter works and how part 2 will play out:
- Weighing the food items we are to sample
- Reading the temperature of the water
- Recording the data
- Assembling the calorimeter system
- Filling the water into the calorimeter
- Selecting a sample from our food items
- Heating the food in the calorimeter
- Reading the temperature of the water
- Recording the data
- Calculation
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