Q&A for How to Build a Hydrometer

Return to Full Article

Coming soon

Add New Question

Question

Can I use homeade play dough?

Bess Ruff, MA
Environmental Scientist
Bess Ruff is a Geography PhD student at Florida State University. She received her MA in Environmental Science and Management from the University of California, Santa Barbara in 2016. She has conducted survey work for marine spatial planning projects in the Caribbean and provided research support as a graduate fellow for the Sustainable Fisheries Group.

Bess Ruff, MA

Environmental Scientist

Expert Answer

Play dough is not as hardy as modeling clay and, depending on how you make it, is usually water soluble, meaning it will start to disintegrate when in contact with water. This would make for an ineffective weight for your straw, so play dough is not recommended.

Thanks! We're glad this was helpful.
Thank you for your feedback.
If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
Yes No

Not Helpful 6 Helpful 16
Question

How do you mark the hydrometer?

Community Answer

Put permanent ink markings on the straw. Calibrate with liquids of known s.g.

Thanks! We're glad this was helpful.
Thank you for your feedback.
If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
Yes No

Not Helpful 9 Helpful 16
Question

Can you explain why a straw and clay can function as a hydrometer?

Community Answer

A hydrometer measures the density of liquids. The more salt there is in water, the better an object would float. The clay at the bottom of the straw keeps the straw upright, while the straw has markings on it to show how much salt is in the solution.

Thanks! We're glad this was helpful.
Thank you for your feedback.
If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
Yes No

Not Helpful 6 Helpful 9
Question

Are there other materials I can use besides clay?

Community Answer

Sculpy works great, as it’s waterproof and is supplied in craft stores.

Thanks! We're glad this was helpful.
Thank you for your feedback.
If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
Yes No

Not Helpful 0 Helpful 2
Question

Why do I need a ball of clay?

Community Answer

You need it to weigh down your straw so it can work. Otherwise, it will float to the top and fall out.

Thanks! We're glad this was helpful.
Thank you for your feedback.
If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
Yes No

Not Helpful 0 Helpful 1