كتاب الطالب العلوم منهج انجليزي الصف السادس الفصل الأول 2022 -2023
IT's ALIVE! Or is it
You have been invited by scientists to work on a special project involving the possibility of life on another planet. Your job is to help decide whether or not life has been found in outer space. Astronauts were able to travel to a nearby planet and gather samples. Some of the samples appear to be living, but the scientists don't know for sure
Your goal is to determine whether or not the samples are living by conducting an investigation to show what living things are made of, and developing and using a model Of the building blocks of a living thing to show how all living things, from yourself to the microscopic amoeba at the beginning of the project, perform functions to stay alive. You will present your investigation and model to a panel of scientists
After You Read Exploring Life
In your Science Notebook, list the steps in your investigation to show whether the samples are living or nonliving
How will scientists conclude whether the samples from the other planet are living or nonliving After You Read Cell Structure and Function Answer the following questions in your Science Notebook
What will be the parts in your model, and how will you show what each part represents
How will your model show the function of the system as a whole and the ways each part contributes to the function as a whole
How will your model help the scientists determine whether the samples are living or nonliving
Look at the planning you did after each lesson. use that information to complete the Plan for your investigation in your Science Notebook, and build your model
PRIMARY SOURCE
Observation XVIII of the Texture of Cork Robert Hooke, 1665
I took a good clear Piece of Cork, and with a Pen- knife sherpen'd as keen as a Razor. I cut a piccc of it off. and thereby left the surface of it exceeding smooth. then examining it very diligently with a Microscope. mc thought J could perceive it to appear a little porous; but I could not so plainly distinguish them, as to bc sure that they were pores much less what Figure they wore of : But judging from the lightness and yielding quality of the Cork. that certainly the texture could not be so curious. but that possibly, if I could use some further diligence, I might find it to be discernable with a Microscope. I With the same sharp Penknife. cut off from the former smooth surface an exceeding thin piece of it, and placing it on a black Object Plate, because it was itself a white body. and casting the light on it with a deep plano-convex Glass. I could exceeding plainly perceive it to be all perforated and porous. much like a Honey-comb. but that the pores of it were not regular; yet it was not unlike a Honey-comb in these particulars
First. in that it had a very little solid substance, in comparison Of the empty cavity that was contain'd between
Next. in that these pores. or cells. were not very deep. but consisted Of a great many little Boxes
Source: Project Gutenberg
How have microscopes helped people learn about
EXPLORE / EXPLAIN Lesson: Exploring Life
Since the development of the cell theory in the 1830s microscopes have continued to become more advanced. If you have used a microscope in school. then you have probably used a light microscope. Light microscopes use light and lenses to enlarge an image of an object. Light microscopes can enlarge images up to 1,500 times their original size. In some cases the object , such as the blood cells in the photo on the right, must be stained with a dye in order to see any details
You might know that electrons are tiny particles inside atoms. Electron microscopes use a magnetic field to focus a beam of electrons through an object or onto an object's surface An electron microscope can magnify an image 100,000 times or more. The two main types of electron microscopes are transmission electron microscopes (TEMs) and scanning electron microscopes (SEMs)
TEMs are usually used to study extremely small things such as cell structures. In a TEM, electrons pass through the object and a computer produces an image of the object A TEM image of an intestinal microvilli is shown on the right
SEMs are usually used to study an object's surface. In an SEM, electrons bounce off the object and a computer produces a three- dimensional image of the object. An image of blood cells from an SEM is shown. Note the difference in detail in this image compared to the image of blood cells from a light microscope
Microbiologists study living things that are too small to be seen with the unaided eye. such as bacteria. algae, and fungi. Some microbiologists also study viruses, Without microscopes, the field of microbiology and the industries it supports. such as the food and medical industnes, would not be the same today
A typical day in the life of a microbiologist depends on what specific field of microbiology he or she works in. Some microbiologists focus solely on certain organisms. such as bacteria. some focus on the ways in which microorganisms interact with the environment'. and some focus on ways to detect. treat, and prevent diseases caused by microorganisms
Microbiologists spend much of their time preparing the samples that they study. conducting expenments. and writing reports on their findings. Since their specimens cannot be seen with the unaided eye. microbiologists use microscopes. along with many other technologies. In their work
It's Your Turn
Suppose that you are planning on getting a college degree in microbiology. Which area of microbiology would you like to focus on ? Research the different fields and specialties of microbiology and then choose the one that interests you the most. Write a paragraph explaining the field of microbiology that you have selected and why that field interests you
ELABORATE Lesson : Exploring Life