This unit deals with the speed of objects. Speed is a basic concept used to quantify an object s movement, which can be measured by positional changes over time. It is important to express an object s speed objectively and scientifically. In this unit, students come to understand an object s movement in terms of positional changes and learn how to compare the speed of objects through different methods. They also measure the speed of a variety of objects, such as athletic performances, forms of transportation and recognize that they should control an object s speed for safety reasons.
The grade 5 English science unit, Speed, meets the academic content standards set in the Korean curriculum, which state students should: a) Understand an object s movement as positional changes over time and understand an object s speed qualitatively by observing a moving object. b) Be able to compare the speed of objects by measuring the time it takes for the objects to move as certain distance. c) Be able to compare the speed of objects by measuring the distance that the objects move within a given time. d) Be able to calculate an object s speed by measuring the distance it moves and the time required.
What do I need to do? You will need aluminum foil, corkboard, a pin, paper, a bowl, a straw, water, and a stopwatch. 1. Use the corkboard, pin and paper to make a small boat that can float in water. 2. Unroll all the aluminum foil in a straight line. Fold up the edges so that it can hold water. Fill it with water. 3. Put the boat at one end of the foil. Use a straw to blow it to the other end. Use a stopwatch to time it. Draw pictures to show what happened. You can see that things move if their position changes as time passes. For example, if you look at the tiger in the first picture below, the tiger is in front of some trees. In the second picture, however, the tiger is now ahead of those same trees. In the final picture, the tiger is closer to the trees at the end of the picture. 1 second 2 seconds 3 seconds 1. How did you know the boat was moving? 2. How could you make your boat move faster? 1
What do I need to do? You will need a spool, a washer, a toothpick, a straw or pencil, an elastic band, and tape. 1. Put the elastic band through the spool. Break a toothpick so that it is smaller than the diameter of the spool and put it through the elastic band loop. Put tape over it. 2. Put the elastic band through the washer on the other end of the spool. Put a straw through the loop and wind up the elastic band. Group Complete the chart. 3. Make a racetrack and race against your friends. Record your places in the chart. Position Have you ever read The Hare and the Tortoise? Who had the fastest speed? Speed can be understood by measuring how fast an object moves. We can see how fast or slow something is by looking at the distance something moves in a certain amount of time. 1 second 2 seconds 3 seconds You can see that the tiger in the second group of pictures is faster than the tiger in the pictures above it because it has moved a farther distance in the same amount of time. 1. Which group had the fastest wind-up racer? How did you know this? 2. How could you make your wind-up racer go faster? 2
What do I need to do? You will need a radar gun, and a baseball. 1. Set the radar gun directly behind the thrower. 2. Have someone pull the radar gun trigger as the person throws the ball. 3. Record the speed in the chart. Do this 3 times. Complete the chart. Name Attempt 1 Attempt 2 Attempt 3 Radar guns have been made that can calculate the speed of something without you having to physically measure the distance and time. They are often used in sports to show how fast sprinters run, how fast someone s serve is in tennis, or how fast a pitcher throws a baseball. On September 24, 2010, against the San Diego Padres, Chapman was clocked at 169.1 km/h, which is the fastest pitch ever recorded in Major League Baseball. 1. How do radar guns make it easy to measure speed? 2. How could you throw faster? 3
What do I need to do? You will need an exercise bike. 1. Make sure that the information on the exercise bikes is reset to 0 and set it on the time option. 2. Sit on the exercise bike and wait for the teacher to say Go! Ride the bike as fast as you can for 10 seconds. 3. After 10 seconds, remove your feet from the pedals. Change the bike option to distance to see how far you rode. Complete the chart. Name Distance in 10 seconds People like to race each other. They want to be the fastest. The speed of people can be compared by measuring the distance that people move in a given time. In other words, speed can be calculated using the following equation; Speed = Distance / Time Distance is usually measured in kilometers or meters. Time is usually measured in hours or seconds. This means your answer will be either km/h or m/s. 1. Calculate your speed in m/s. Show your working out. 2. Who had the fastest speed in your group? What does this actually mean? 4
What do I need to do? You will need a toy train, train tracks, a stopwatch, a tape measure, and a calculator. 1. Put together the train tracks in a straight line and measure the distance. 2. Put the toy train at the start. Turn it to slow mode and start the stopwatch. Complete the chart. 3. Time how long it takes for the train to get to the other end. Stop the stopwatch. Do it 3 times. Do the activity again with the train on fast mode. Slow Trials Distance (m) Time (s) Speed Fast Trials Distance (m) Time (s) Speed 1 1 2 2 3 3 When calculating the speed of real cars or trains, it is best to use km/h. This is because cars and trains can travel a long distance over a long time. However, it would be strange to calculate the speed of a toy in km/h because toys only travel a small distance and are usually much slower. It makes more sense to calculate the speeds of toy cars and trains in m/s. If you use km/h for toys, the numbers would be really small and difficult to write and say. 1. Why was it best to calculate the speed of the toy train in m/s? 2. What units would you use to measure the speed of a real airplane? Why? 5
What do I need to do? You will need a toy car, roads, a stopwatch, a tape measure, and a calculator. 1. Connect the car tracks together to make a loop. Connect the top part of the track to your desk or a wall. 2. Put the car at different heights up the slope. Check what the lowest height would be for the car to go around the loop. Complete the charts. 3. Calculate the speeds of the cars that successfully completed the loop course. Remember you need to think about the distance the car went and the time it took. Car Height Cleared (o/x) Speed 10cm 20cm 30cm 40cm 50cm Car Height Cleared (o/x) Speed 60cm 70cm 80cm 90cm 100cm When a roller coaster is at the top of the tracks, it has a lot of potential energy. Potential energy is the stored energy an object has because of its height. As the rollercoaster starts to go down the slope, its potential energy changes into kinetic energy. Kinetic energy is the energy of movement. The faster something moves, the more kinetic energy it has. If an object doesn t have enough kinetic energy, it won t be able to get up slopes. Scientists use their understanding of potential energy and kinetic energy to make rollercoasters work. 1. Why couldn t some cars make it through the loop? 2. What height gave the car its greatest kinetic energy? What proof do you have? 6
What do I need to do? You will need A4 paper, paper airplane instructions, scissors, a tape measure, a stopwatch, and a calculator. 1. Use the super stunt plane instructions to make the paper plane. Throw it. Time how long it takes to fly and how far it went. Calculate its speed. 2. Use the graceful glider instructions to make the paper plane. Throw it. Time how long it takes to fly and how far it went. Calculate its speed. There are four forces that affect flight. They are lift, thrust, drag and weight. Complete the chart. 3. Make an original paper plane design. Have a contest to see whose plane can go the longest distance. You can also check to see whose plane had the fastest and slowest speeds. Plane Type Distance (m) Time (s) Speed (m/s) Super Stunt Graceful Glider Original Design Lift is the force that makes planes go up. The air travels a longer distance over the wing in the same time it takes for the air to travel under the wing. This lifts the wings up. Thrust is the force that makes the plane go forward. In real planes, this is from its engine, but with your paper plane, it comes from your muscle power. Drag is friction from the air. When the plane goes forward, air hits the plane and slows it down. A plane with a sharp front reduces drag. Weight is what pulls the plane to the ground. Lift must overcome gravity to keep the plane in the air. 1. What is the key to making a paper plane fly a long distance and have the greatest speed? 2. What caused your plane to move in different directions? 7
What do I need to do? You will need paper, scissors, and paper clips. 1. Use paper that is twice as long as it is wide. Cut two slits halfway down that are about one third of the width. Fold one side to make a strip. 2. Fold the bottom over and add a paperclip. Cut the top part down the middle to make the blades. 3. Fold one blade to the front and the other to the back. Drop it from a high place. Try changing the length of the blades and adding more paperclips. Describe what happened or draw a picture to show what happened. Helicopters have blades that spin around quickly. The blades are tilted to provide thrust. Thrust is the force that allows the helicopter to move forward. However, helicopters can travel in any direction or just hover in the sky. As your paper helicopter falls through the sky, air pushes up against the blades. This causes the blades to spin. The air pushing up also makes your helicopter fall slower. The larger the blades, the slower your helicopter will fall because more air is pushing against the blades. 1. How did the length of the blades affect its speed? 2. How did the helicopter s weight affect the helicopter s speed? 8
What do I need to do? You will need plastic bags, strings, a ruler, scissors, markers, tape, pegs or some other weight, a stopwatch and a tape measure. 1. Get a large plastic bag. Measure a 30cm x 30cm square and cut it out. Make 3 more squares that are different sizes, so that you will have a total of 4 parachutes. 2. Tape 4 pieces of string that are all the same length to the corners of the plastic. Join the strings together in the middle and connect with pegs. Complete the chart. 3. Drop the parachutes from a high place. Measure the distance the parachutes fall. Time how long it takes for the different parachutes to reach the ground. Parachute Size Distance (m) Time (s) Speed (m/s) 30 x 30 Gravity pulls things to the ground. Objects that are high in the sky will fall back to the Earth very quickly. Parachutes can be used to bring people and things sent into space slowly and safely back down to the ground. When parachutes open, some of the air rushing past gets caught in the parachute. This creates greater air resistance. Larger parachutes can trap more air, making the parachute fall slower. 1. Why do parachutes allow things to fall back to Earth slowly? 2. How does the size of a parachute affect its speed? 9
What do I need to do? You will need a folder, scissors, tape, pencils, two skewers, two thin straws, two flexible straws, four pet bottle caps, a hammer, and a nail. 1. Fold the top of your folder in half and design the top of your car. Use the back of the folder to cut out a base that is about 9cm wide. Stick on straws and insert skewers that have pet bottle caps on them. 2. Cut the end of a balloon off. Insert two straws inside the balloon and tape them there so air doesn t escape. Attach these straws to the back of the car. 3. Blow through the straws to inflate your balloon. Pinch the balloon to keep the air in. Then, place your car on the ground and let go. Race your friends. Describe what happened or draw a picture to show what happened. Real sports cars and racing cars are designed to be sleek, or pointed. This means that as the car moves through the wind, air can move around the car very quickly. We say these cars are streamlined, which allows them to move very fast. However, speeding can be very dangerous. A speed limit is usually displayed on a sign and shows how fast you are legally allowed to travel on that road. Speed limits are often set to stop people driving too fast. It is done to improve road traffic safety and to reduce the number of injuries and deaths caused by people crashing. 1. What car design allows a car to move fast? Why? 2. Why is going too fast dangerous? 10