Hey there! I'm happy to help!
Observations are things that can be written down or described. You can observe something with any of your five senses: you can see what color something turns, you can hear the noise something makes, you can taste a cookie with a different amount of an ingredient, you can smell an odor produced by a chemical reaction, and you can feel the texture of different samples.
You can also create observations by using scientific tools. For example, instead of feeling if water is hot or cold, you could use a thermometer. This will give you numerical data which can be put into a table or graphed for further analyzing.
Inferences are created from observation. You cannot make an inference without observation. Observations lead to inferences. Inferences are conclusions or guesses made from the observations. You could infer that sugar makes a cookie taste sweeter after experimenting with no sugar and observing that it tasted bitter. You could infer that more weight allows things to travel further after going down a ramp after measuring the distances different weights travel, graphing it, and observing the data.
Have a wonderful day and keep on learning! :D