Understanding Potential Energy in Grade 7 Natural Sciences
Potential energy, a form of stored energy, is vital in various systems and objects. From objects held above the ground to stretched elastic bands, potential energy plays a crucial role in everyday concepts. This energy is exemplified in scenarios like books on a table ready to drop and the potential energy derived from the food we consume for daily sustenance and growth. Through engaging illustrations and examples, Grade 7 students delve into the significance of potential energy and its transformative role in different contexts.
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Natural Sciences Grade 7 Term 3: Energy and Change Potential and kinetic energy
Topic 2 Potential and Kinetic Energy Potential energy Natural Sciences - Grade 7
Potential energy Potential energy It is energy that: - has the capacity to do work. - is stored in a system. A system: - consists of an input, a process and an output. - is made up of two or more parts that work together. - needs energy to work. Natural Sciences - Grade 7
Potential energy Potential energy All objects that are held above the ground have potential energy. Potential energy is also stored in fuel, batteries and food. Natural Sciences - Grade 7
Potential energy examples Potential energy examples A brick that lies on the ground does not have any potential energy. Once the brick is picked up, it has the ability (potential) to fall down to the ground. Natural Sciences - Grade 7
Potential energy examples Potential energy examples A stretched elastic band has high potential energy. The energy used to stretch the elastic band, remains stored in the elastic band until you let it go. Natural Sciences - Grade 7
Potential energy examples Potential energy examples Books on a table: Books that rest on a table has potential energy, since it is above the ground. The potential energy is only available when it drops on the floor. Natural Sciences - Grade 7
Potential energy in food Potential energy in food Our energy to keep on living comes from the food that we eat. Our bodies turn the potential energy in food into energy for living and growing. Energy is measured in joules (j). [joules are small amounts of energy]. People use kilojoules (kJ) [1 kJ = 1 000 J]. Natural Sciences - Grade 7
Potential energy in food Potential energy in food It is very important to check the kilojoules listed on food s packaging. Food labels have nutritional information that inform us how much energy the food contains per serving. Adults need approximately 8 000 kJ of energy per day from food. The next slide has a table with food that children prefer to eat. Natural Sciences - Grade 7
FOOD ANALYSIS FOOD ANALYSIS KILOJOULES KILOJOULES Standard serving Food kJ 100g kJ Beef steak [no fat] 1 serving [168g] Baked beans Fried chicken Egg Potato crisps 1 179 918 238 702 340 1 385 594 2 090 1 serving [270g] 1 serving [72g] medium [15g] 1 serving [50g] 71 1 045 Natural Sciences - Grade 7
FOOD ANALYSIS FOOD ANALYSIS KILOJOULES KILOJOULES Standard serving 1 serving [100g] 1 cup [237g] 1 can [355g] 2 tbsp. [32g] 1 serving [30g] 1 med. [138g] 1 small [50g] Food kJ 100g kJ Pizza slice Water (tap) Soda soft drink Peanut butter Bread (white) Apple Carrot 910 910 0 630 788 334 301 86 0 180 2 462 1 049 218 173 Natural Sciences - Grade 7
Important information on food Important information on food packages packages Lean: described on meat, poultry, seafood and game meat. - Less than 10g fat, 4.5g or less saturated fat, and less than 95mg cholesterol per reference amount or per 100 grams. Extra lean: described on meat, poultry, seafood and game meat. - Less than 5g fat, less than 2g saturated fat and less than 95mg cholesterol per reference amount or per 100 grams. . Natural Sciences - Grade 7
Important information on food Important information on food packages packages Good Source: the reference amount of a product contains 10 to 19% of the Daily Value of a particular nutrient (i.e. fibre, protein / a vitamin / a mineral). High: the reference amount of a product contains 20% or more of the Daily Value for a particular nutrient (i.e. fibre, protein / a vitamin / a mineral). Natural Sciences - Grade 7
