Home > Articles

  • Print
  • + Share This
This chapter is from the book

The Submarine

A submarine can both submerge and rise to the top of the water. What's the trick?

Version 1: Step By Step

Supplies

  • 2-quart (2-liter) plastic bottle

  • balloon

  • plastic tubing, approx. 3 feet (1 m) in length

  • silverware (3 or 4 table knives)

  • kitchen sink or pail

Make two holes roughly 1 to 1 1/2 in (3 to 4 cm) in diameter in the upper and lower parts of the bottle, as shown in the figure. Insert one end of the tubing in the opening of the balloon. (It needs to fit snugly; use masking tape if necessary.) Place the knives (ballast) inside the bottle through the holes in the side. Insert the end of the tubing with the balloon into the mouth of the bottle and position the balloon in the middle of the bottle. Your new submarine is ready. Put it on the bottom of the sink or in a pail. Fill the sink or pail with water until it covers your submarine. In order to not waste water, test your submarine when you are washing dishes in the kitchen sink. Blow into the free end of the tubing and see what happens.

Fun Facts

If there were water in the balloon instead of air, the mass of the water would be about a thousand times greater than that of the air contained in the balloon. Density is a measure of the quantity of matter (mass) per unit volume. We can then say that water is a thousand times denser than the air in the balloon. When the balloon fills, the submarine rises so that more water—higher density—will remain at a lower depth in the sink or pail, and the air—lower density—will remain above. In this way, more matter (mass) will remain closer to the Earth's surface. This is a result of the gravitational attraction exerted by the Earth. Otherwise, we would simply float! This happens when we are in a swimming pool, for example, and our lungs are full of air. As soon as we let the air out of our lungs, we start sinking, just as happens with the "submarine" when we let the air out of the balloon.

Version 2: Step By Step

Supplies

  • 2 party balloons

  • 2 coins

  • 2 plastic bottles, 1 large, 1 small, both with screw-on caps

  • masking tape

  • water

Remove as much air as you can from the balloons. (If necessary, roll them as if they were almost empty tubes of tooth paste.) Insert the coins in the openings of the balloons. (The coins act as valves.) Put the balloons in the bottles, fill the bottles with water, and put the caps on tightly. The small amount of air that remains in the balloons will make them float, as shown. Ask someone to press one of the bottles while you press the other. Discover which of the bottles permits you to make the submarine submerge more easily.

A. Squeeze

Tightly cap an empty plastic bottle, then squeeze it as hard as you can with your hands. You will certainly be able to deform it (at least temporarily). Try to deform a bottle filled with water, as in the experiment with submarines. The small amount of air in the bottle can be compressed, to a certain point. The water cannot, and for this reason it is said to be incompressible.

B. Blow

Make small holes in a plastic soda bottle in various places with a pin or needle. Blow through the mouth of the bottle and feel the air coming out of the holes with your fingers. Fill the bottle with water and cap it well. (If the holes are small enough, hardly any water will come out of them.) Squeeze the bottle. (Be careful! Water will squirt out of all the holes in all directions, like in a shower.) With this experiment, you show that pressure propagates in all directions in a fluid, including air (you can repeat the experiment with the bottle empty).

Fun Facts

The submarine experiments demonstrate that any externally applied pressure is transmitted undiminished to all parts of an enclosed fluid (for example, air or water). Considering that the two plastic bottles in version 2 have different surface areas, when you squeeze them with the same force, you produce a different pressure in the water inside the bottles. This extra pressure, in its turn, forces the balloons to shrink, thus increasing effectively their average density. Eventually, when the applied pressure is large enough, the "submarines" will sink. Now, which bottle will sink more easily?

Version 3 : Step By Step

Supplies

  • plastic tube from a pen, with one end capped/sealed

  • small vial, such as from a sample of perfume, or a dropper

  • wooden matchstick

  • plastic bottle with screw-on cap

  • water

Fill the tube (submarine) with water until it is almost filled, leaving only a small air bubble at the top. Fill the bottle with water and place the submarine inside so that it is suspended vertically. Close the bottle tightly and then press its sides with both hands, as the picture shows. What about using now the wooden matchstick as a submarine?

Fun Facts

This version is just a variant of the previous model. In the present case, when you squeeze the bottle, the extra pressure produced inside the plastic tube squeezes the air bubble, shrinking it, hence increasing the average density of the submarine. In a real submarine, the effect you produced with your hands is made with suction pumps. They pump water into ballast tanks, effectively increasing the average density of the submarine until it submerges. To surface, they pump the water back out into the ocean, decreasing the average density of the submarine until the submarine rises to the surface. Although ships are made of materials denser than water, they don't sink. This happens because most of the ship's space is filled with air. If the ship's weight plus its load exceeds a certain value, the ship will inevitably sink, just as the submarine does with its ballast tanks full of water. Now, what happens if the bottle is not completely filled with water or if it has a small hole at its top or at its bottom? Will the submarine work the same way?

  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020