California Registered Dental Assistant (RDA) Written Practice Exam

When gypsum materials are mixed, how are the powder and water incorporated?

1. Add water to the powder

2. Add powder to the water

3. Mix simultaneously

4. Neither is added to the other; they are mixed separately

The correct answer is: Add powder to the water

When mixing gypsum materials, it is important to add the powder to the water, not the other way around. This is because if water is added to the powder, it can result in clumps and uneven distribution of the powder, leading to a weaker final product. Mixing the powder into the water allows for better incorporation and a more consistent mixture. Option A is incorrect because it suggests adding water to the powder. Option C is incorrect because mixing simultaneously can result in uneven distribution as the powder may not fully mix with the water. Option D is incorrect because it suggests mixing the powder and water separately, which would not result in a proper mixture.