Driving Science Home

Transcription

1 Driving Science Home What makes a car go? The power of tension? The invisible force of magnets? The energy of fuel? Investigate how energy and the forces of motion get cars moving. Turn your house into an engineering lab and try these fun, hands-on experiments. You even get to taste some of your experimental results. Buckle up and get ready for a moving experience!

2 InTENSE Science: Build a Tension-Powered Car If you loop a rubber band around your index fingers, and pull your fingers apart, you will feel a pulling force between your fingers as the band becomes more difficult to stretch. This force is called tension. Let s see how we can use tension to power a mini-car. Materials one clean 1-litre milk carton one bulldog paperclip two skewers, cut to 14 cm in length four Styrofoam balls rubber bands weight (such as a set of keys) scissors, tape, and glue construction paper and decorations 1. Lay your carton (the car body) on its side. On the side facing up, cut two openings, leaving a strip of cardboard in the middle for support. 2. Turn the carton over, and cut a slit where the carton top meets its side. 3. Insert the bulldog clip in the slit, and unfold the handles so they lie flat. Secure a rubber band to the inside handle. 4. Pierce two holes in each side of the carton to hold the skewers (the car s axels). Insert one skewer through the holes in the front of the car, and the other through the holes in the back make sure the skewers turn freely. 5. Pierce the centre of one Styrofoam ball (one of the car s wheels), and glue it to one end of the front skewer. Pierce another Styrofoam ball, and glue it to the other end of the front skewer. 6. Tie the loose end of the rubber band to the centre of the rear skewer. If the rubber band is too short to reach, and still remain loose, add one more. 7. Repeat step 5 for the rear skewer. 8. Decorate your car with construction paper and whatever else you like. Now it s time to race your car. Wind its rear wheels backwards the rubber band will wrap around the axel. Keeping hold of the wheels, place your car on the floor. Release the wheels and zoom! the car should speed forward. Add a bit of weight, like a set of keys, to the back of your car to help it move farther. When you wind up the rear wheels of your car, the rubber band wraps around the axle, adding tension to the rubber band. When you release the wheels, you release the tension and the rubber band pulls itself back to its original shape. The rubber band unwinding from the car s axle causes the axel and wheels to turn, which moves the car forward.

3 Precious Cargo: Build an Egg-Mobile Cars are designed with special safety features to protect the passengers in case of a crash. You can design your own car safety features with household materials to protect your very precious cargo an egg! Materials string (a few metres in length) eggs 10 rubber bands uncooked spaghetti straw tape 1. Using 10 rubber bands and uncooked spaghetti, design and build a vehicle (egg-mobile) that will protect your passenger (the egg) in a collision. 2. Use tape to securely attach a straw to your egg-mobile. 3. Thread the string through the straw of your egg-mobile. 4. Tape one end of the string to a wall. Attach the other end of the string to another wall, on an angle so that one end of the string is higher than the other end. This will be the track for your egg-mobile. 5. Release your egg-mobile from the higher end of the string and see if it survives the collision with the wall at the bottom. Make sure you test your eggmobile in an area that is easy to clean, in case your egg is injured during the test. The spaghetti acts as a protective frame around the egg. The frame of a real car is made with special crumple zones that are designed to crumple in a collision. We want the metal to crumple so that it will absorb some of the energy from the impact of the crash. The rubber bands act as a seatbelt keeping the egg in place. Seatbelts are designed to keep passengers from flying forward in a collision. We need seatbelts because of inertia. Inertia means that an object at rest will stay at rest and an object in motion will stay in motion at the same speed until a force acts on it. This means that in a crash, even though your car has stopped moving, your body will continue to move as fast as the car was moving, unless a force in this case, your seatbelt stops it.

4 Magnet-mobile Magnets have amazing invisible forces. Use this force to make a magnet-mobile that appears to move on its own. Materials 2 magnets 2 small stickers (or small pieces of tape) small toy car tape 1. Try bringing the sides of the magnets together, and identify the poles the ends or sides of a magnet where the magnetic force is strongest that repel each other. Mark these poles with a small sticker. 2. Tape one magnet on the toy car, near the back, with the sticker facing out. 3. Without touching the car, hold the other magnet near the back of the car, with the stickers facing each other. Observe what happens. When you brought the two magnets close to each other, you may have noticed that the car began to move. This is because when like poles of two magnets are brought together, the magnets repel the magnetic fields push away from each other. The magnet attached to the car was pushing away from the magnet in your hand, making the car appear to move on its own. Magnets have an invisible force by which they can attract or repel certain objects. This invisible force is called a magnetic field. It attracts metallic materials like iron and attracts or repels other magnets. This magnetic field gives a magnet two poles north and south. Placing opposite poles together causes magnets to attract. Placing like poles together causes magnets to repel. The north and south ends of the Earth are called the north and south poles. Because of the Earth s ironnickel core, the Earth itself acts as a magnet with two poles and an enormous magnetic field.

5 Rubber Tire Treats Rubber Tire Treats are tasty gummy candies that result from a bit of kitchenchemistry magic. Make these jiggly treats and explore the science of polymers. Ingredients 1 small box of purple Jell-O 7 envelopes unflavoured gelatin 250 ml water round candy moulds 1. Place the Jell-O, gelatin, and water in a saucepan and mix until the mixture looks like dough. 2. Place the pan over low heat and stir the mixture until it is completely melted. 3. Pour the mixture into round plastic candy moulds. 4. Put the moulds in the freezer for 5 minutes, and then place them in the refrigerator for another 5 minutes. 5. When the candies are very firm, remove them from the moulds and enjoy. If you like sour gummies, you can spritz them lightly with water and sprinkle them with kosher sour salt (also known as ascorbic acid or vitamin C powder). Be safe in the kitchen. Always get an adult to help you whenever you re cooking. The gelatin in Jell-O is made of long chains of flexible molecules called polymers. When the Jell-O mixture is hot, the bonds holding the chains together are broken, the molecules slide past each other easily, and the mixture acts like a liquid. But as the mixture cools, new bonds are formed, and the mixture becomes a rubbery solid. Real car tires are a lot like the treats you ve just made. The rubber used to produce car tires is made from a runny, milky-white liquid called latex, which is also a polymer. Latex makes rubber tires strong but flexible.

6 Fuel Your Body: Make a Car Cake Your body is like a car: it needs fuel to work. It runs on the fuel it gets from the food you eat so fuel your body with this yummy car-shaped cake. Ingredients 2 sheet cakes plastic straws, cut in half 1 can of icing chocolate bars and candy (to decorate) 4 Rubber Tire Treats (see previous recipe) 1. Bake two standard sheet cakes in the flavour of your choice. You can bake the cake from scratch or use a cake mix. 2. Remove the sheet cakes from the pan and let them cool for at least one hour. 3. Push three plastic straws, about 2 inches apart and forming a triangle, into the middle of one of the cakes. This cake will serve as the bottom of the car. The straws provide support for the top layer. 4. Cut the second sheet cake in half. Place one of the halves centred on top of the first cake. This is the car s top. Make sure you position the second cake on the straws and press down gently. The straws keep the second cake firmly on top of the first. 5. Ice both cakes. 6. Place a large rectangle of chocolate on the front of the second layer to serve as the car's windshield. Add smaller squares on the sides to serve as windows. 7. Use four Rubber Tire Treats for car wheels. Decorate using your favourite candy. Cake is a good source of sugar and will give you lots of energy. However, the best energy is found in fruits, vegetables, dairy, grains, and meat. Be sure to eat healthy foods to fuel your body. Our bodies are like cars they need fuel to function. Fuel is a source of energy. Cars use fuels such as gasoline, diesel, or ethanol to provide the motor with the energy to run. Our bodies require different types of fuels carbohydrates, fats, and proteins. Each of these is found in different foods we eat. Once in our stomach, these fuels are broken down to give us the energy we need to move, talk, think, and learn.

7 Experiments clean 1-litre milk carton bulldog paperclip 2 skewers 4 Styrofoam balls rubber bands weight (e.g., a set of keys) scissors tape glue construction paper and decorations string eggs uncooked spaghetti plastic straws 2 magnets small stickers small toy car Recipes small box of purple Jell-O 7 envelopes unflavoured gelatin 2 sheet cakes plastic straws 1 can of icing chocolate bars and candy round candy moulds Movie The Love Bug, (Walt Disney Productions, 1969) Book My Car, by Byron Barton, (Greenwillow Books, 2003) Web link What on Earth! is an animated short film featuring a crew of extraterrestrial visitors to Earth who assume that cars are the dominant race, and humans are merely parasites.