Year 5 Topic 4 Switched on Science Lets
- Slides: 30
Year 5, Topic 4, Switched on Science Let’s get moving
Key Vocabulary • • • Gravity Weight Newton Non-contact Isaac Newton Galileo Friction Air resistance Water resistance • • • Force meter Reliable Lever Spring Gear Pulley Machine Rube Goldberg Force
In this topic you will: explain some of the effects of gravity plan, carry out and explain fair tests observe forces that slow things down find out about water and air resistance explain how levers, gears, pulleys and springs transfer forces and motion • design a Rube Goldberg machine. • • •
Unit 1: Forces of nature Can you: • • explain what makes objects fall to the Earth? use a force meter to weigh objects? understand how gravity works on Earth? investigate falling objects in detail?
Let’s think like scientists • • What is gravity? What does gravity do? Where do you find gravity? Can you see gravity? If not, how do you know it is there? What would happen if there was no gravity? What would happen if the force of gravity on Earth was bigger?
Right or wrong? Are the following ideas right or wrong? • Heavy objects fall faster than lighter objects. • The force of gravity varies in different places on Earth. • Objects always come to a stop when there is no friction.
Answers • No. They appear to due to air resistance, not due to weight. • No. The force of gravity is the same on Earth. • No. Objects will not come to a stop without friction.
Did you know? • Sir Isaac Newton was the first person to think of the force of gravity and describe its effects. • Albert Einstein did not think it was a force at all. He said it was a distortion of space and time. Sounds very complicated!
Facts about gravity • Gravity is a force that pulls objects towards the centre of the Earth. • Any two objects have a force of gravity acting between them. • This becomes more noticeable when the objects are huge in size (think about the Earth and the Sun).
Which way does gravity pull on Earth? • Gravity pulls things towards each other – like apples and the Earth. • No matter where you are on Earth, the apple always falls downwards towards the centre of the Earth. • Apples have weight. Weight is the name given to how much something is pulled down by gravity.
Measuring weight • Use a force meter to measure the weight of a variety of objects in your classroom. • Design a table to record your results. • Remember - weight is a force and measured in units called Newtons.
Investigate falling parachutes Plan a fair test to investigate how well parachutes of different designs fall to Earth. What equipment will you need? What factors will you • keep the same? • change? • measure? How will you record and make sense of your results?
Unit 2: It’s a drag Can you: • explain what friction is? • explain what air and water resistance are? • plan and carry out a fair test to investigate water and air resistance? • present and explain your results well? • explain how ships and planes are designed to reduce water and air resistance?
Let’s think like scientists • What is the best way to plan a fair test? • How might you make it as accurate and reliable as possible? • What do you do if some of the results do not look sensible? • In what ways can you present your results?
Right or wrong? Are the following ideas right or wrong? • Friction only occurs between solid surfaces. • Air resistance makes things move faster. • Submarines are designed to reduce water resistance.
Answers • No. Its also occurs between solids and liquids, solids and gases, and between liquids and gases. • No. It slows things down. • Yes. Their shape helps them to move faster through the water.
Did you know? • Modern submarines have a teardrop-shaped hull to help them reduce water resistance.
Investigate friction Plan a fair test to investigate how well objects slide on different surfaces. What equipment will you need? What factors will you • keep the same? • change? • measure? How will you record and make sense of your results?
Investigate forces Plan a fair test to investigate the size of the force needed to pull a variety of trainers across different surfaces. What equipment, besides a force meter, will you need? What factors will you • keep the same? • change? • measure? How will you record and make sense of your results?
Investigate streamlining Plan a fair test to investigate how fast different shapes of plasticine fall through water. What equipment will you need? What factors will you • keep the same? • change? • measure? How will you make your results reliable? How will you record and make sense of your results?
Unit 3: Magnificent machines Can you: • explain how levers, springs, pulleys and gears transmit force and motion? • make some simple machines? • design and make a Rube Goldberg machine?
Right or wrong? Are the following ideas right or wrong? • The bigger the gear on a bike, the faster it moves. • Machines are always complicated. • Pulleys are a modern invention.
Answers • No. It depends on the number of ‘teeth’ in the two gears. • No. Some machines like a lever are very simple. • No. Pulleys were used by the ancient Egyptians.
Did you know? Some racing bikes can have as many as 33 gears!
What can levers do? • Levers can change the direction of a force or magnify it (make it bigger). • Good examples are crowbars, scissors and bottle openers.
What can gears do? • Gears are wheels with teeth that fit together. • When one moves, the other moves the opposite way. • Gears are found in watches, some toys, bikes and cars.
What can pulleys do? • A pulley is a wheel fixed at one end with a rope passing through it. • When the rope is pulled, it can lift an object more easily.
What can springs do? • Springs come in lots of different shapes. • This one is found inside a watch. • Springs work by storing energy.
Simple machine All these are machines: • • Levers Screws Wheels and axles Pulleys Gears Springs Ramps
Make your own Rube Goldberg Machine • • Think up a good design. What machines does it use? What will you need to collect? How will you build it? How will you test it? How could you make it better? What is the best one made in your class?
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