Let’s see how you did! If you didn’t get a few of these, don’t let it stress you out – it just means you need to play with more experiments in this area. We’re all works in progress, and we have our entire lifetime to puzzle together the mysteries of the universe!
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Answers:
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- Does it matter the time of day when using a solar cell? Yes, the sun’s angle to the solar cell will change the power generated.
- What does temperature measure? The average speed of the molecules in a substance.
- How can we store energy in water for later use? A large container of salt water can absorb heat energy during the day and release it during the evening because in a salt water pond, the warmer water is trapped below the surface of the water under an insulating layer and does not escape through convention.
- What are common problems with windmills? No-wind conditions and storms.
- What are three different kinds of batteries, and what is their limitation? Dry cells (found in flashlights and portable radios), mercury batteries (inside cameras and watches), and lead storage batteries (car batteries). Most batteries are non-reversible and cannot be recharged, making them single-use.
- What is the difference between dehydration and hydration, and why is this important? Dehydrated means to remove the water from a substance. Hydrated magnesium sulfate requires heat when combined with water to break the ions, and will become cold (endothermic). Dehydrated magnesium sulfate generates heat when combined with water and becomes warm (exothermic).
- Name two ways a house can save money on energy bills during the summer. With proper insulation to keep the cool air indoors and decrease the heat transfer through walls, windows, and doors; surround the house with shady trees to decrease the air conditioner’s work load by keeping the house out of direct sunlight.
- How can we get fuel from a peanut? A peanut is not a nut, but a seed which has proteins, fat, and carbohydrates. The oil (fat and carbs) from the peanut can be ignited and the energy is released in the form of heat and light.
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