1. Move the decimal point: Move the decimal point to the right until you have a number between 1 and 10. In this case, you'd move it three places to the right:
0.0024 --> 2.4
2. Count the moves: You moved the decimal point three places to the right.
3. The exponent: Since you moved the decimal to the *right*, the exponent will be negative. The number of places you moved it determines the exponent: -3.
4. Put it together:
2.4 x 10⁻³
Therefore, 0.0024 in scientific notation is 2.4 x 10⁻³