11/22 MS Chemistry update and homework due 12/6

Hi folks,

First off, NO CLASS, next week due to Thanksgiving.  I hope everyone has a holiday full of safe journeys and tasty turkey.

This week in class, we took the time to review everything we've done so far this year.  To do so, we had a game show.  For the first half of class the students looked through all their notes and quizzes and created at least five questions for the game show.  The rest of class is the challenge of each team answering the questions to earn points.  It's a lot of fun and a great way to review the year. 

For homework this week please do the enclosed .pdf.  It's a review of everything we've covered so far this year.  I've included the answers as well so that you can check yourself when you are done.  It is certainly a possible possibility that you may see many of these questions again so I would HIGHLY recommend making sure you know the answers to all of them.  Just a little gift from Turkey Claus.  :)

 

11/15 MS Chemistry Class and homework due 11/22

Hi folks,

This week in class we took our knowledge of density one step further as we got into the concept of density.  As part of today's work I gave the students a challenge of creating a boat that held the most weight possible.  The winner's boats each held 7 batteries before sinking!  Quite impressive.

For homework this week, please answer the following questions.  Answers are below.

You may need to check your notes or rewatch parts of the video to answer these yourself.

1.  What is the definition of density?

2.  If I have a bowling ball and a golf ball and the bowling ball floats while the golf ball sinks, which one has a greater density?  (Be sure to think about this one for a bit before your answer.)

3.  One of the examples I gave in class was of everyone in class trying to hold up a 200 lb beach ball and then trying to hold up a 200 lb mattress.  How did that apply to buoyancy?  

4.  If something displaces as much water as it weighs, does it float or sink?

5.  Think about the Bill Nye video.  When the boat displaced the water in the tank, Bill Nye put the water on a balance scale with the boat.  How did the weight of the water compare with the weight of the boat?  Was it more, less or the same?

6.  If you put a boat in a tub that weighed 5 pounds and measured the weight of the water that the boat displaced, how much would the water weigh?  

7.  If you crumple aluminum foil into a small ball it will sink but if you make that same amount of foil into a boat it will float.  Why?

8.  The winning boats (the boats that held the most batteries) all had sides.  Why are sides helpful?

9.  If an aircraft carrier weighs 40,000 tons, what is the weight of the water it must displace to float?

10.  If something has a density greater than the density of the liquid it is floating in, will it float or sink?

11.  Water has a density of 1 g/ml.  If an apple has a density of .87 g/ml will it float or sink?

12.  If a penny has a density of 3 g/ml will it float or sink?

Answers (Please be sure to try all the questions first.  Also, if you get something wrong, know what you did wrong.  Remember, these may all be on a quiz someday.)

1.  Density is the amount of matter in a given space.

2.  The golf ball. Strange huh.  But if it sinks that means its density is greater than water, the bowling ball must have a density less that water.

3.  Since the mattress was large, everyone could get under it and help hold it up.  Since the ball was smaller only a few folks could help, so you couldn't hold it.  Buoyancy is similar.  The larger the object is, the more water can be underneath it to hold it up.  Or, in other words, the more water will be displaced.

4.  It floats!

5.  It was the same.  If you displace the amount of water you weight, you float.

6.  5 lbs.

7.  If you spread out the material, more water it can displace.  Once it displaces its weight in water, it will float.  

8.  Sides keep the water from coming into the boat.  If water comes in, now you need to hold the batteries and the water.  Also, sides allow the boat to displace even more water.

9.  40,000 tons!  That's a lot of water.

10.  Sink

11.  Float

12.  Sink

11/15 MS Chemistry Recording - Buoyancy

https://youtu.be/u1J0ll7qXAI

11/8 MS Chemistry Recording - A bit more density

https://youtu.be/iwz0e4W1m4A

11/8 MS Chemistry update and homework due 11/15

Hi folks,

Today we got a bit deeper into density by having the students measure multiples of different objects.  As we were doing the lab we noticed that it didn't matter how many pennies we had or how much water we had, the density always stayed the same.  This is because density is a ratio of mass and volume.  It doesn't matter how much you have, any substance will aways have the same density.  

For homework this week I want you to take your new found density finding skills and put them to good use at home.    Find the densities of three different objects.  You can use the immersion technique or the measuring technique (especially if it's something you don't want to put in water) to find the volume and then use a scale to get the mass of an object.  You may not have the same type of equipment that we do in class but I bet you have measuring cups and a scale in your kitchen.  Do the best you can and see what you find.

Want some extra credit??  Do 6 things instead of just 3.

Just to be clear as to what I'm looking for this week.   When you hand in your homework, I'd like to see a data table with the object, the mass, the volume and the density.

Here's an example.

Have fun!

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