1. 7.1 The Nature of Matter pp. 166 - 169 Mr. Richter

2. Agenda  Warm-Up  Check In about Science Fair  Introduction to Heat  Notes:  What Are Atoms?  Brownian Motion

3. Objectives: We Will Be Able To…  Define and explain the terms atom and element.  Explain Brownian Motion and how it supports the theory that matter is made up of tiny, invisible particles.

4. Warm-Up:  What do you think an atom is?  Discuss at your table. Then write a one-sentence definition in your own words.

5. Hot or Cold?

6. What are Atoms?

7.  Atoms are very small things.  An atom is the smallest particle of matter that still retains the chemical properties of that type of matter.  An atom of gold is the smallest piece of gold there can be and still behave like gold.  If you cut an atom of gold, it will no longer be gold.

8. What are Atoms?  How small are atoms?  Atoms are measured on the scale of 10 -10 meters. Or 1 atom is approximately 0.0000000001 meters wide.  Or in other words, in 1 meter, you can fit about 10,000,000,000 atoms side by side.  There are 350,000 times more atoms in single cup of water than there are cups of water in the all of world’s oceans.

9. What is an Element?  An element is a pure substance that cannot be broken down into simpler substances by any physical or chemical means.  Atoms are the smallest possible pieces of elements that still behave like the element.  e.g. same melting point, strength, etc.  Each element has a unique type of atom.  All atoms of carbon are pretty much the same as each other, but different than atoms of oxygen.

10. Combinations of Elements  When elements are grouped together, they make the everyday substances that you and I are familiar with.  Water, wood, humans, dirt, etc.  Depending on how the elements are combined, the combinations are called either:  compounds  mixtures, or  solutions  You will learn more about this in Chemistry.

11. Brownian Motion How do we know atoms exist?

12. Brownian Motion  Individual atoms are much much smaller than we can see, so how do we know they exist?  In 1827, Robert Brown observed that particles of pollen floating in water moved in a “herky jerky” random path.

13. Brownian Motion  It was as if the particles of pollen were being hit by many smaller particles. Later, Einstein concluded these particles were atoms.  The random movement of particles because of their collisions with atoms is called Brownian Motion in Brown’s honor.

14. Brownian Motion

15. Wrap-Up: Did we meet our objectives?  Define and explain the terms atom and element.  Explain Brownian Motion and how it supports the theory that matter is made up of tiny, invisible particles.

16. Homework  p 169 #1 (1 full paragraph)  Define “atom” and “element” in your own words.