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Measurements and the Process of Science

Learning Plan 1. Measurements and the Process of Science

Target Competency

1. Apply basic chemistry methods and measurements. (Ch.1)


Part A.
Choose something to observe in your environment (e.g., sugar dissolving in Kool Aid, pasta cooking, alka seltzer dissolving in water, vinegar reacting with baking soda, etc.).

Make a list of all the observations you can make (at least 10).
Now, from this list of observations, come up with a hypothesis that you can test.
Design an experiment that could be run to test your hypothesis.
Be sure to follow the steps of the scientific method in setting up your experimental report.

You do not need to perform the experiment. You will be graded on your initial observations, hypothesis and written experimental report.

Part B.

a. If we assume the density of blood is 1.060 g/mL, what is the mass of 6.56 pints of blood in grams?

b. A patient weighs 146 pounds and is to receive a drug at a dosage of 45.0 mg per kg of body weight.
The drug is supplied as a solution that contains 25.0 mg of drug per mL of solution.
How many mL of the drug should the patient receive?

c. A typical aspirin tablet contains 5.00 grains of pure aspirin analgesic compound. The rest of the tablet is starch. How many aspirin tablets can be made from 50.0 g of pure aspirin?

d. What Fahrenheit temperature corresponds to 37.0 degrees C?

e. If a person smokes 10.0 packs of cigarettes a week and each cigarette contains 5.00 mg of tar, how many weeks will she have to smoke to inhale 0.250 pounds of tar? [Use: 20 cigarettes = 1 pack]

f. A patient needs 0.300 g of a solid drug preparation per day. How many 10.0 mg tablets must be given to the patient per day?

Part C

In two paragraphs, discuss the terms precision and accuracy in relation to significant digits.

In your discussion, address how significant digits relate to the measuring device, and why rules for significant digits are needed for calculations involving measurements.

Solution Preview

Part A
For this part you can really do anything you want. But let's use the example of the sugar dissolving in Kool Aid to show you what they want.

Sample Observations:
what is the color of the solution?, is there any solid in the glass?, does it totally dissolve?, how much sugar is dumped in?, etc.

Sample Hypothesis:
What amount of Kool-Aid mix and sugar needed to make 4 ounces of water into a great tasting drink?

Experiment Design:
Add different amounts of sugar to the kool aid and taste them to come up with the best amount.
For instance...1/4 teaspoon, 1/2 teaspoon, 1 teaspoon, etc

Scientific Method:
Here is a summary of the scientific method:
1 Ask a Question
2 Do Background Research
3 Construct a Hypothesis
4 Test Your Hypothesis by Doing an Experiment
5 Analyze Your Data and Draw a Conclusion
6 Communicate Your Results

Part B - This part has mostly to do with conversions.

a. "If we assume the density of blood is 1.060 g/mL, what is the mass of 6.56 pints of blood in grams?"

The keys to this problem are two two things. One is converting from pints to mL, the other is using the equation for density (D = M/V).
First we need to convert pints to mL in order to ...

Solution Summary

This solution answers various questions pertaining to measurements and the process of science.