10/18 Chemistry update and homework due 10/25

Hi folks,

Today we talked about conservation of energy and then began work with temperature and heat. We did a lab today where we heated a solution of rubbing alcohol and water and recorded the temperature every 30 seconds. Next week we will discuss our findings.

Homework for this week is
Read pgs 17-22

Do questions #'s 22- 29

Also, take the data that you collected from today's lab and create a line graph. Use time as the horizontal axis and temperature as the vertical axis.

10/11 Chemistry Class Recording: Energy 2

Here's the recording for this weeks class.

http://www.youtube.com/watch?v=Cm20YE0rV4A&feature=em-upload_owner

10/11 Chemistry update and homework due 10/18

Hi folks,

Today we did our second part of the "Basics of Energy" lecture were we talked a bit more about what energy is and how to measure it.  We talked about Joules, calories and kilocalories.  We tried to get a feel for the units by doing the physical labor of deep knee bends and pushing my car.  

Homework for this week:

Read the content on this website up to the section on Power.  

Answer the following questions.

1.  How many Joules would it take to walk up a 2 meter (about 6 feet) flight of stairs if you weigh 100 lbs?  (Remember to convert to Newtons.)  How many calories would that be?  How many times would you have to walk up (remember down doesn't count) that flight of stairs to burn off the Calories from a Snickers bar (250 Calories (remember that's 250,000 calories))?

2.  Why doesn't down count in the above problem?

3.  If it takes about 10 lbs of force to push a lawn mower and you push it 400 meters to cover the entire lawn, how much work do you do?  In Joules?  In calories? (Remember to convert to Newtons.)

4.  A gallon of gas has 1.3x10^8 J of energy. (that carrot means that the 8 is an exponent.  So the number is 1.3 x 10 to the 8th.) How far can a car go if it takes 400 N of force to keep it going?

5.  What is potential energy?  Give 3 examples.

6.  What is kinetic energy?  Give 3 examples.

7.  If it takes 10,000 J of energy to push a refrigerator 4 m (12 ish ft.) across a kitchen what force does it take to push that fridge?

8.  Look up 3 of your favorite activities and tell me how many Calories it takes to do them?  How many Joules would that be?

    

10/4 Chemistry update and homework due 10/11

Hi folks,

This week we did a brief introduction to the concept of energy. For the next several weeks we will be looking at energy, temperature, heat and heat transfer. This first block is one of the most "mathy" of the year and uses the most difficult equation that we'll be using this year as well. To prepare for that, I'd like you to do the enclosed .pdf for homework this week. It's my hope that it will help you see how equations are really just another way of communicating.

9/27 Chemistry update and homework due 10/4

Hi folks,

This week we worked on the fairly difficult concept of density. I had the students find the volumes of a block, a cylinder, and a sphere using measurements and math. We also found the volume of several more objects by immersing them in water and seeing how much water was displaced. After finding many volumes, we then went on to take a look at the density of the different objects.

Homework for this week is:

Finish finding the densities of the different objects we measured in class (if you didn't finish that already during class).

In the chemistry book Read pgs. 26-28 including the part in green on page 27.

Do questions #41-44 on pg. 33
Do problems # 5 and 6 on page 35

Problems with the answer key for chem homework

Hi folks,

The answer key is questionable for questions 25-30.  Be careful with those. :)

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"Science Jim"  Mueller

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