The boiling point of water is 100 °C, but in a pressure cooker water boils at a higher temperature. Do chickpeas soften earlier or later in a pressure cooker? Explain why.
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Why are heating radiators placed near the floor and not on the ceiling? (Hint: think about what happens to air when it is heated and how its density changes).
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When we pour a cola with ice into a glass, after a while the outside of the glass becomes wet. Where does this water come from if the glass has no holes? (Hint: look at the temperature of the glass and the water vapour in the air).
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Salt is spread on icy roads to lower the freezing point, so ice melts at colder temperatures. To cool a soda can faster, which works better: ice water or ice water with salt? Explain why.
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When someone sprays perfume in one corner of the classroom, after a while it can be smelled everywhere. What would happen if the room were warmer? (Hint: think about how fast particles move when temperature increases).
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In a refrigerator, some foods need to be kept colder than others to last longer. Where should you place these foods: on the top shelves or on the bottom shelves? Explain why.
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Water can be found in solid (ice), liquid (water) and gaseous (water vapour) states. In which states can water be compressed and in which states can it not? Explain why. (Hint: think about the distance between particles in each state).
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In a fire, people are advised to move out while staying low or close to the floor. Why is it safer to go low instead of standing up?
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