(
课件网) To understand the listening material about an experiment. To learn to use words which indicate the stages of a progress. To learn to write a report about experiment. To describe a simple scientific experiment. You will hear a conversation in which a teacher helps a student do an experiment. Read the Aim below and predict the Result. Aim: To find out if there is a change in weight when the metal magnesium burns in air. Result: _____. Aim: _____ _____ To find out if there’s a change in weight when magnesium burns in air. Listen and complete the description of the scientific experiment. Apparatus: _____ _____ Method: _____ _____ _____ _____ _____ _____ _____ Magnesium, Bunsen burner, a balance, a crucible. First, put the magnesium in the crucible. Then put the crucible on the balance and weigh it. Next, heat the magnesium. Light the Bunsen burner and hold the crucible over it. Finally weigh the magnesium again. Result: _____ Conclusion: _____ _____ It weighs a little more than before. There is a change in weight when magnesium burns in air. Mr C=Mr Chen, ZK=Zhou Kai, LK=Li Kang Mr C: OK, boys and girls, we’re going to do an e _____ closer. _____ you are, _____ you’ll see! That’s right! Now, what’s the _____ of this experiment, Zhou Kai The closer a bit the more Listen and fill in the blanks. aim Z.K: We want to _____ if there’s a change in _____ when magnesium burns _____. Mr C: That’s right. So what do we _____ ZK: Um… We need some magnesium. How much do we need What about this piece Is this piece OK need first find out in air weight Mr C: No, we need _____ more than that—about two and a half grams. We need a piece which is _____ than that. ZK: OK… And we need a _____ _____ … _____ … and _____ to put the metal in … Here they all are … Where do we _____ rather bigger much bunsen burner a balance crucible a go from here Mr C: Well, ____, put the magnesium in the crucible. _____ put the crucible on the balance and weigh it. ZK: OK… Mr C: How much does it _____ Take a look, everyone. Is it any heavier ZK: Um… It weighs _____ grams. Do you want me to write that down first Then two and a half weigh Mr C: Yes, write it down. _____ ZK: Yes… Um, next, we’re going to heat the magnesium. So I light the Bunsen burner. _____, I hold the crucible over it… Oh look, it’s burning with a white light! It’s getting _____! Mr C: It’s pretty, isn’t _____, boys and girls, please. What next After that brighter and brighter Keep the noise down ZK: Um… _____, we need to weigh the magnesium again… It weighs four grams now. Mr C: So what does that tell you ZK: It weighs _____ more than before. Mr C: How much more ZK: _____ grams more. Mr C: And what does that mean 1.5 a little lastly ZK: It means that there is _____ in weight when magnesium burns in air. Mr C: _____! Well done! So now, let’s do the same experiment with copper. _____. Li Kang, _____ now. What do you think will happen if ... ...
