Praxis: Float, float, float your boat
By Patty Rooks on August 3, 2019.
praxis@praxismh.ca@PraxisMedHat As the weather continues to heat up outside I am in search of fantastic science activities so I can cool off from the hot days we have been experiencing. Don’t get me wrong, before we know it, dare I say it will be -40 C and will be wishing it was summer once again. With that being said, I hope you are able to get outside and enjoy the fabulous weather while we have it, and do not forget to do a little experimenting in the meantime! Let’s get started! *Remember to ask an adult before doing this experiment. Materials – outdoor kiddie pool filled with water – tin foil – ruler – rocks/marbles/large washers – marker – scissors – science helper Procedure 1. Measure a 20 cm x 20 cm square of aluminum foil. Cut this out. 2. This is where your imagination comes into play; the challenge is to fold your boat into a shape that will hold the most weight. Feel free to make this into a competition with your science helper to see who can design the best boat. If you want to make it even more competitive, I only give five minutes for this step! 3. Place the boat in the pool of water. 4. Slowly add the weights one at a time to the boat. 5. How many will your boat hold before sinking? 6. Who has the better design? 7. Try changing your design to see what will hold more weight. What is going on? In this experiment, you are learning about the scientific concept of buoyancy. Simply put, buoyancy is the force that a liquid exerts on a floating object. When you place your boat on top of the water in the pool, it pushes water out of the way, or displaces it. I know that this may be difficult to see (trust me!). If the weight of the boat is less than the weight of the water it displaces, it will float! The displaced water pushes back in to the space where the boat is and that is what creates the upward force keeping the boat afloat on the surface of the water. I have often wondered how those large ships float in the water. They are so big! Did you know there are three factors that will affect a boat’s ability to float: Shape, size and the material from which it is made? As you know, boats come in all kinds of sizes and shapes; canoes, rafts, tug boats, cargo ships, etc. In this activity, you tested different boat shapes. The larger the surface area of the boat bottom, the more water it displaces and the higher it will sit in the water. The purpose of the boat plays a major role in its shape. An oil tanker, for example, carries a very heavy load of oil and travels through shallow waters in harbours, so it must float higher in water. Therefore, it is very long and narrow, giving it a large bottom. The depth of water a boat needs to float is called its draught. A large ship with a load can draw up to 20 metres of water. Don’t forget to get in touch with me (via email please) if you have not registered for our Teacher Workshop featuring Coding in the Classroom coming up on Aug. 13. I have had a couple of spots open up!! Patty Rooks, Senior Scientific Consultant PRAXIS, “Connecting Science To The Community”. Contact Praxis at praxis@praxismh.ca, http://www.praxismh.ca, Tweet or follow us @PraxisMedHat, or friend us on Facebook. You can find us at: #12 826 11 Street S. E., Medicine Hat, Alberta, T1A 1T7 Phone: 403.527.5365, email: praxis@praxismh.ca. 25-24
