I know you just finished the density derby challenge, but I have another one for you. Here’s the challenge. Devise a way in which you can lift a person by using your breath — OK I know what some of you are thinking — I don’t mean to knock someone off their feet with your bad breath!

I haven’t tried this myself yet, but I heard it can be done. I’ll be experimenting during the week to see if I can do it.

Test your ideas and the first person to successfully demonstrate this in class will earn 10 points on their next test.

Good Luck.

Congratulations on the many fine entries in the Density Derby Challenge, you showed creativity and understanding of the principles of density. Next week we’ll continue to look at forces in fluids examining buoyancy and Bernoulli’s Principle.

Here’s a link that explains how Galileo’s thermometer works. Check it out.

Density Derby Challenge:

#1-5 to be submitted by each student:

1) Written quality observations of at least 5 demonstration stations (20 points)

2) Answers to day 1 questions, should be at least 5 questions (20 points)

3) Filled test tube with substances in the proper order (1 point each, max 20 points)

4) Scientific explanation of how Galileo’s Thermometer works (20 points)

5) Scientific explanation of how your derby entry will work (20 points, plus this is required to submit an entry object)

#6 One derby entry per table

6) Derby entry results (100 points)

- object either sinks or floats — 70 pts
- object sinks and floats — 80 pts
- object sinks then floats within 50-70 seconds — 90 pts
- object sinks, stays down for 60 seconds (rounded to the nearest whole second) then floats — 100 pts

How are you progressing on your Density Derby Challenge?

1) Are you answering the questions from day 1? You should write the answers in your notebook. Here are just a couple of things we asked:

• Does weight determine if something floats or sinks?
• Does surface area make any difference?
• What about size?
• What is density?

2) List objects/substances we worked with in the lab and their densities. Now determine if they would float or sink in water. Imagine a huge test tube and you are placing all the objects and substances into this test tube. What order would they settle. List them from bottom to top.

3) How do you calculate density? (not just the formula, give examples of what we did in class)

4) What causes something to float of sink in water?

5) Have you seen anything float then sink, or sink then float?

6) Explain how the Galileo Thermometer works.

Monday you will be working on and testing your challenge entry. Tuesday you will present your entry in class (1 per table).

Remember you must have a written scientific explanation of how/why your entry will work. All objects are to be made from things you can find around the house. You can not purchase an item designed to to do this. I will not supply materials.

Have a great weekend!