Whether you're up for a Crocodile Dundee's adventure or you'd just like a taste of the Australian sun, the beaches in and around Sydney can offer you all that and more.

Sydney Beach

    Sydney Beach is located at Sydney's northernmost tip on an extension(延伸) of land ending at Palm Beach. Before checking out the golden sand, take a quick tour of the houses of millionaires from the art and film industries.

Palm Beach

    Only about an hour from downtown Sydney, Palm Beach offers a long stretch(延伸) of clean sand and water. With parking near the center of the beach, that leaves the rest of it as a peaceful location with a sparse population, from which you can go surfing but take care — without the huge crowds of other Sydney's beaches, Palm Beach doesn't afford quite the safety level to be found elsewhere. Volunteer lifesavers are on duty only on weekends and holidays.

Bondi Beach

    For the famous beach, Bondi Beach has to be your choice. Parking is difficult to find even on slow days, so consider taking public transport to this world—known beach in the eastern Sydney suburbs. Easily reachable by taxi, bus, and rail, Bondi Beach offers sun bathing, swimming, snorkeling, and all sorts of water sports fun. If you're in the mood for a bit of exercise, two scenic coastal walks will afford you great views and sights along the shore. Take in views from Mackenzie's Point. It starts at Bondi and heads south to Bronte Beach. But don't try to swim in Mackenzie's Bay — it holds dangers such as hidden rocks.

Bronte Beach

    Your second choice for a scenic coastal walk covers a few miles and takes you from Bronte Beach to Waverly Cemetery, where many famous Australians are buried, including the poet Henry Lawson.

加碘盐有必要吃吗

阮光锋

       ①有人说，碘盐吃多了会得甲亢，尤其是沿海地区的人经常吃海产品，所以不需要吃碘盐。这是真的吗？吃碘盐真的会导致碘超标吗？

       ②其实，就目前我们的膳食情况来看，不论是沿海居民还是内陆居民，都需要吃碘盐。

       ③碘是身体必需的微量元素。在我们脖子上有个腺体叫甲状腺，它需要碘来生成甲状腺素，甲状腺素具有加快新陈代谢，促进生长发育尤其是脑发育的作用。如果缺碘，将会影响大脑发育，容易引发克丁病和大脖子病。

       ④碘的饮食来源主要包括食物、加碘食盐及饮用水。含碘丰富的食物主要有海带、紫菜和海鱼等。不过，国际上公认的防治碘缺乏病的主导措施就是食盐加碘。为什么呢？调查显示，无论是在低碘还是高碘地区，海带、紫菜、海鱼等传统观念中的补碘食物对于碘的摄入量都贡献甚微。因为这些食物虽然含碘量较高，但占人类膳食的比例太小。而且海盐本身其实也不含碘的。在沿海地区，碘盐仍是当地居民重要的碘来源，不通过食盐补充的话，碘摄入量就会不足。所以，即便生活在海边，仍然需要食用含碘盐。很多人担心碘吃多了会得甲状腺疾病，这是过于担心了。世界卫生组织认为，每日碘摄入量在1000微克以下一般是安全的。正常饮食的话，普通人的碘摄入基本不会超过这个量。

       ⑤很多人认为碘盐是中国特色，其他国家都不这样做，其实，恰恰相反。食盐加碘是世界卫生组织在全球推行的预防和控制碘缺乏病的策略。世界卫生组织推荐食盐中的碘添加量为20-40毫克/千克，而我国食盐的碘添加量低于这一标准，目前为20-30毫克/千克。

                                                                                                                                                                            （选自《百科知识》，有删改）

小明将一个西瓜和一个梨子放入水缸中，发现西瓜浮在水面上，而梨子却沉入水底，请你画出西瓜所受力的示意图