Volumetric flask:

Looking up, the concentration of the prepared solution becomes smaller, because the solution is prepared with a volumetric flask. When looking up, I mistakenly thought that the liquid level was low, and continued to add water to increase the solvent and reduce the solution concentration.

Measuring cylinder:

Looking up makes the reading smaller. Measuring cylinders are used to measure solutions. When you look up, you mistakenly think that the liquid level is low, which makes the reading smaller.

Buret:

When the burette is checked, the experimental data is small, because the titrated solution is used to titrate and calculate the titrated solution. After the titration reaches the end point, the burette looks up and mistakenly thinks that the liquid level is low, so the volume brought into the calculation is small, resulting in a small calculation result.

Looking down is the opposite.