• Problems due Friday are: • Chapter 1 problems: C1B.1, C1B.2, C1B.3,

C1B.4, and C1S.5.• Thursday the lab will be for each person to

measure the height of the two flagpoles, write a discussion of your uncertainty in that height and write a discussion comparing your results with two other students.

• The test over chapters one and two is scheduled for Friday, September 3.

• Problems due next Wednesday are: Chapter 2 problems: C2B.1, C2B.2, C2B.4, C2B.7, C2B.8, C2B.9 and C2S.1 Ask questions about them Monday.

Lab tomorrow

• How to measure the heights of the two flagpoles.

Physics lecture

Wednesday, August 26Fall 2010

Each individual must write on a sheet of paper what he/she thinks science to be. (you have 3 minutes)

• This is not to test what you learned from out text, this is to obtain your “gut” feeling about science.

• Your definition must not contain the phrase “scientific method” or a synonym of this term.

• What sets science apart from the other ways of “knowing” or “learning”.

• Your group now has 3 min to arrive at a consensus and put your result on the board.

One physicist’s opinion

• Science is a way to study nature and natural phenomena that uses nature itself as the final authority. The experiment determines who is right.

• Man’s guess about how God does things.

• Measurement is a fundamental aspect of science, especially physics.

Physics for biologists• Studying a physics text is much different

than reading a biology text.• What is active reading?

• Being sure you understand the process• In this class we are much more interested in

the process of arriving at the answer than whether or not you arrive at the correct answer.

• When you learn the process, the correct answers will come

• Credit on homework will be given for process even if the final answer is not obtained or is incorrect.

• For this reason be sure your process is clear from what you put on your paper.

• The same is true for tests.

Naming the ideas behind physics• All the ideas of physics fit into one of

two large categories these are:• Standard model

• Everything except gravity• Including motion, electricity, thermodynamics,

chemistry, biology• General Relativity

• Explains gravity and other long range effects.• You should remember these two and when

they apply• You need not be concerned with the details of the

diagrams on pages 6 and 7.

Noether’s Theorem• Conservation of energy

• Means physical laws do not change in time

• Conservation of linear momentum • Means physical laws are the same

anyplace in the Universe.• Conservation of angular momentum

• Means physical laws are the same regardless of how you are oriented•Same in all directions.

• The most important idea this year

The structure of matter(Part of the standard model)

• Large objects are made of atoms• Atoms are made of electrons, protons and

neutrons.• All these particles are made of elementary

particles.• Electrons are examples of leptons• The proton and the neutron are the only

combination of quarks that last more than a millionth of a second.

• One current theory says that all elementary particles are made of strings (of energy).

This theory accounts for all types of mass.

• What quarks make the proton?• See page 11

• What quarks make the neutron?

What is meant by the term “interaction”?

• Each person is to write in their own words a definition of “interaction”. (3 minutes)• Try to use words a non-science

person can understand.

• In your groups arrive at a common answer and put it on the Board.

Gault’s attempt at defining interaction.

• Something that must happen for one object to affect another object.• If there is no interaction between

objects, one does not affect the other in any way.

• Your definition may be better.

Types of interactions

• Macroscopic• Distance• Contact

• Between quarks inside the nucleus• Strong nuclear - 1• Weak nuclear - 2

• Between charged particles• Electromagnetic - 3

• Between any particles that have mass• Gravitational - 4

• Only these four types of interaction exist• As far as we know today!

Describe the interactions on the swinging object.

• Each group has 2 min to name the interactions and then write them on the blackboard

Velocity

• The speed of an object is the distance traveled per unit time (for example the number of meters per second).

• We find that interactions do not necessarily change the speed but they always change either the speed or the direction.

Vector

• It is therefore convenient to define something that includes both the speed and the direction of a moving object.

• We call this the Velocity.• When a physical quantity includes both

size (magnitude) and direction, we call it a vector.

Units

• Learn the standard prefixes from tera to pico. (page – 17 and front cover of text)

• Always show your units in all calculations.• Example: Change grams to English tons (2000

lbs)

• On both problems and tests, every mark on the above is required!

ton

grams

ton

lbs

kglbs

kggrams

51005.92000

21.2

1000

The unit operator method

• Suppose there are 3 gob/tow, 7 rem/tow, 5poy/gob and 9 poy/in.

• 10 in is how many rem? • Begin with what you know and

eliminate units you don’t want working toward the units you do want.

in10

in

poy9poy

gob

5 gob

tow

3 tow

rem7

10 in = 42 rem

Units

• In your groups:• Use the unit operator method to

calculate the number of seconds in a century. Each person is to do the calculation on a paper in front of them clearly showing all steps.

• Compare answers at your table.• When all at your table agree, write the

answer on the board (showing your work).

Problems:

• You should have been working on these problems.

• Hand them in at the beginning of lecture on Friday.

• Chapter 1 problems: C1B.1, C1B.2, C1B.3, C1B.4, C1S.5, and C1R.1

• You should have tried the chapter 1 problems. If you have any questions ask them now. They are due as you arrive in class next Wednesday.

• You should begin work on the chapter 2 problems.

• Both labs should be finished and handed in today if at all possible.

• Lab Tuesday will be on vectors.• Both labs meet next Thursday.