How to Convert Units of Measure!

Summary

This video provides a detailed, step-by-step guide to converting units of measurement, an essential skill in science subjects like chemistry, physics, and biology. The instructor focuses on a methodical, long-form approach, avoiding shortcuts to help beginners or those struggling with conversions. Using examples like converting centimeters to meters and milligrams to grams, the video walks viewers through identifying conversion ratios, writing fractions, and canceling out units, all while emphasizing the importance of accuracy. The video also touches on significant figures and best practices for avoiding common mistakes.

Takeaways

• 🔢 Converting units is an essential skill in science, as it's needed in almost every problem in subjects like chemistry, physics, and biology.
• 📝 The method explained in the video focuses on a step-by-step process that avoids shortcuts to ensure a clear understanding of unit conversions.
• 📐 Step 1 is identifying the conversion ratio between the units being converted. For example, 100 centimeters equals 1 meter.
• 📊 Step 2 involves writing the conversion ratio as two possible fractions, with either unit on top, like 100 cm/1 m or 1 m/100 cm.
• ➗ Step 3 is writing the given number as a fraction with units, which helps track what needs to be canceled out later in the process.
• 🔄 Step 4 is choosing the correct conversion fraction, multiplying, and solving. This involves canceling out units and simplifying.
• ❌ It's important to cancel out units properly, as this is key to getting the correct answer. If units don't cancel out, the conversion is incorrect.
• 🧮 Using a calculator is helpful for solving the multiplication, especially in cases where decimals or fractions are involved.
• ✔️ Always double-check the final answer, making sure it follows any specific rules such as significant figures, especially in science classes.
• 💡 Practice problems help solidify the method, and the video recommends a detailed approach to avoid common mistakes in unit conversion.

Q & A

What is the first step when converting units?

The first step is to identify your conversion ratio, which defines the relationship between the two units you're converting between. For example, 100 centimeters equals 1 meter.

Why is it important to write your conversion ratio as two possible fractions?

Writing the conversion ratio as two possible fractions, with either unit on top, helps you choose the correct one based on which unit you need to cancel out during the conversion process.

How should you represent your given number in a unit conversion problem?

You should represent your given number as a fraction with the unit in the numerator and a denominator of 1, even if the original number is not shown as a fraction. For example, 16 centimeters would be written as 16 centimeters over 1.

Why is it important to keep track of units throughout the conversion process?

It's important to keep track of units because they help ensure that you're setting up the problem correctly and canceling out the appropriate units. Dropping units can lead to mistakes and incorrect answers.

How do you know which conversion fraction to use in the problem?

You choose the conversion fraction that allows the units you want to cancel to appear on opposite sides (numerator and denominator). This ensures that the unwanted units cancel out and you are left with the desired unit.

What happens if you choose the wrong conversion fraction?

If you choose the wrong conversion fraction, the units won't cancel out properly, and you'll end up with an incorrect or nonsensical answer, such as squared units or the wrong final unit.

Why is the final answer in the example problem 0.16 meters?

After converting 16 centimeters to meters using the correct conversion ratio (1 meter = 100 centimeters), the result is 16/100, which simplifies to 0.16 meters.

What role do significant figures (sig figs) play in unit conversions?

Significant figures indicate the precision of the given measurements. In unit conversions, the significant figures from the original number should be preserved in the final answer, but conversion ratios like 100 centimeters = 1 meter do not affect the sig figs because they are considered exact.

How do you handle decimal numbers in unit conversions?

Decimal numbers are treated as fractions, with the decimal number and its unit placed in the numerator and 1 in the denominator. For example, 0.685 milligrams would be written as 0.685 milligrams over 1.

How would you convert a fraction like 1/8 liter into milliliters?

First, identify the conversion ratio (1 liter = 1000 milliliters), and then write 1/8 liter as a fraction with liters in the numerator. Multiply it by the appropriate conversion fraction (1000 milliliters over 1 liter), which cancels out liters and gives the result in milliliters.