1. T.O.C: Telescopes Allow us to Study Space from Earth
Ch. 1 Lesson 1.2
How do telescopes work?
T.O.C:
Telescopes Allow us to Study Space from Earth

2. Telescopes Capture Light
Light is a form of radiation that carries info from space
Electromagnetic radiation (EMR)w.w- energy that travels across distances as certain types of waves.
Travels in all directions thru space
Almost everything we know about the universe came from the study of this radiation!
Can tell size, distance, & mvmt of object by its radiation as well as what it’s made of & how it’s changed!
So, how does light allow us to “see” an object then?
Light reflects from object & travels to your eyes. Your eyes gather light from the object you’re looking at!

4. The Electromagnetic Spectrum w.w
All forms of electromagnetic radiation
In order from longest radiation wave to shortest: radio waves, microwaves, infrared, visible (white), ultraviolet, x-rays, gamma rays
About White/Visible Light
– prism/flashlight demo
A tiny part of the electromagnetic spectrum
We can see it, but we see it in colors…
Spectrum(w.w) these colors make up visible light, in order of wavelength- long to short- Red, orange, yellow, green, blue, indigo, violet. (rainbow)
Wavelength(w.w)- distance between one wave peak to the next wave peak.

7. Telescopes (w.w)
Galileo Galilei- 1609/1610- created 1st telescope. Supported Copernicus belief of Sun as center of universe. Discovered moon craters & Jupiter’s 4 large moons.
Device that gathers EMR
Some gather visible light (mine) to provide clear images than what is seen w/ your eyes
Others show radiation that our eyes can’t see
Astronomers use telescopes to gather info about space
Different colors/shades reveal patterns of radiation
Most gather info w/ a glass lense or reflecting surface (like a mirror) & data is gathered electronically.

8. 2 Types of Visible-Light Telescopes
Reflecting- has curved mirror that reflects light
Can be built to gather infrared or ultraviolet radiation
Image focuses on mirror & reflects to eyepiece
Ex: mine
Refracting- has curved piece of glass at one end of a long tube
Gathers light & focuses it to form image at other end of tube
Eyepiece magnifies images
The most powerful telescopes are built on mountain tops in rural areas. Why is this?
Less light from city, less interference w/ our atmosphere b/c less air (air mvmt in atmosphere causes the stars to “twinkle”)

9. Radio Telescopes
Shows where radio waves are being emitted by space objects
Has curved metal surface called a dish (think satellite) that gathers radio waves & focuses them on an antennae which is connected to computers that receive the incoming data
So big b/c radio waves are so long!
A group of these pointed at one object can show more detail than the largest satellite dish.
Not affected by clouds, bad weather, etc. b/c radio waves pass thru Earth’s atmosphere freely.

11. Telescopes in Space
Hubble Space Telescope (see pic)- reflecting telescope.
Placed in Earth’s orbit in 1990 & is operated from Earth
Sends images/data to Earth electronically
Very clear images of space b/c it’s IN space (no atmosphere)
Collects visible, ultraviolet, & infrared radiation images
Just a part of a group of telescopes that orbit Earth & allow astronomers to gain info from electromagnetic spectrum.
Spectroscope Lab- Page 21- create table in Notebook
Need: spectroscopes, flashlight (2), fluorescent lamp (2), blacklight, sunlight
Students in groups. DO: “Observe & Analyze” #1 & “Conclude” #1, 2, 3

12. 1.2 Review Q’s 24 pts What is electromagnetic radiation (EMR)? (2 pts)
What form of EMR is particularly important for humans? Why? (2 pts)
List the forms of electromagnetic radiation in order from longest to shortest wavelength. (7 pts)
List the visible light spectrum in order from longest to shortest wavelength. (7 pts)
Explain how radio telescopes work. (3 pts)
Explain how/why Galileo Galilei’s invention of the telescope was important for science. (3 pts)