Smart Thinker Answers Answers
4B
If there is not enough evidence to support the hypothesis, we should propose a new hypothesis and do a test again. Yes, it will. When scientists find evidence that is inconsistent with the old theory or hypothesis, they will question the accuracy of that theory or hypothesis and propose a new hypothesis. When the new hypothesis passes all the strict tests and is supported by the new evidence, the old knowledge will be replaced. Any reasonable answers, e.g. how nature evolved in the past, the extinction of dinosaurs, the birth of the Earth and the origin of the universe. Any reasonable answers, e.g. hydropower. It is because the amount of water in Hong Kong's rivers has big differences in different seasons. Those rivers may sometimes experience droughts. Therefore, the water resources in Hong Kong are unable to develop large-scale hydropower facilities. During the process of squeezing an orange, the juice is separated from the fruit, but it does not produce new matter. It is similar to the cases of breaking glass or shredding wood. Any reasonable answers, e.g. normal iron nails maintain the hardness of metals, and are difficult to bend and break while rusty iron nails are fragile and can be broken easily. Normal iron nails have better electrical conductivity than rusty iron nails. Rusty iron nails are poor conductors of electricity. Light pollution is caused by the overuse of outdoor lighting. It has negative impacts on ecology and natural environment. For example, streetlights and lights from lightboxes reflect light directly or from buildings into the sky, making the night sky bright and affecting the flying of birds. The light also covers the brightness of stars, making us see fewer stars in the sky. Pupils' own answers, e.g. I want to become an astronaut. To become an astronaut, I should have a strong body to handle extreme situations in space, such as acceleration and weightlessness. I should also have good mental conditions to handle emergencies calmly. Having good scientific and engineering knowledge can help me control spacecrafts and space stations, and complete different space missions.
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