1. Move the decimal point: Start with 630,000.0 and move the decimal point to the left until you have a number between 1 and 10. In this case, you'll move it five places to the left: 6.30000.

2. Count the moves: You moved the decimal point five places to the left. This means you've multiplied the original number by 10^5.

3. Combine the parts: Now you have 6.3 x 10^5. This is 630,000 in scientific notation.

Therefore, 630,000 in scientific notation is 6.3 x 10^5.