6.4 what can you see?
DESCRIPTION
Different models of the Solar System and how beliefs influenced them, How evidence from observations helps improve models, How scientists get evidence about the Universe nowTRANSCRIPT
6.4 What can you see?April 13, 2023
A man and his son were in a car crash. The father died, but the son was critically injured
and rushed to hospital. When he reached the operating table, the doctor on duty
looked at him and said ‘Oh goodness, it's my son!’ How
can this be?
Lesson Learning outcomes Before Learned Revised
6.2 I can look up data in tables. (Level 4)
6.2 I can explain that there is no friction in Space. (Level 4)
6.2 I can remember that gravity holds planets in orbit around the Sun, and the Moon and satellites in orbit around the Earth. (Level 4)
6.3 I can describe the uses of some satellites. (Level 4)
6.4I can describe how models of the Solar System have changed over time. (Level 4)
6.4 I can describe the current model of the Solar System. (Level 4)
6.5 I can describe weight as a force. (Level 4)
6.6 I can explain how scientists use models to describe things (Level 4)
6.2 I can explain how to improve the accuracy of experiments. (Level 5)
6.2 I can explain how friction affects the motion of objects. (Level 5)
6.2 I can explain how to take measurements accurately. (Level 5)
6.3I can explain the difference between natural and artificial satellites. (Level 5)
6.4 I can explain why the Sun seems to move across the sky. (Level 5)
6.5 I can calculate weight from mass. (Level 5)
6.6 I can describe the motion of objects under simple conditions. (Level 5)
6.3 I can relate the properties of a satellite to its use. (Level 6)
6.4 I can relate observations in history to Solar System models. (Level 6)
6.5I can describe the use of gravity meters to explore underground. (Level 6)
6.2 I can explain the link between the gravitational attraction of an object and force and distance. (Level 7)
6.3I can describe the way that gravitational attraction causes satellites to orbit. (Level 7)
6.5 I can explain how a gravity meter works. (Level 7)
6.6 I can describe the motion and gravitational affects of spacecraft visiting the Moon from Earth. (Level 7)
6.2 I can discuss Cavendish’s experiment in detail. (Level 8)
6.3 I can describe the relationship between orbital speed, distance and gravitational attraction. (Level 8)
6.3 I can describe the relationship between planet size, distance from Sun and surface conditions.(Level 8)
6.6 I can explain the limitations and uses of a variety of models. (Level 8)
Learn about
• Different models of the Solar System and how beliefs influenced them
• How evidence from observations helps improve models
• How scientists get evidence about the Universe now
Explaining the Universe
• For thousands of years people have used their observations and beliefs to explain the movements they see in the night sky
• In 550 BCE Pythagoras believed that everything was made of four materials (elements) with fire being the most important
• His model had fire at the centre of the Universe with everything (including the Sun) moving around it
Explaining the Universe
• One hundred years later Plato observed that from the Earth we see the Sun and planets apprarently moving around us
• He came up with a geocentric model
• Aristotle was Plato’s pupil, in his model stars and planets were attached to 56 ‘celestial spheres’ which surround the Earth
Making observations
• In around 100 CE, Ptolemy observed that some planets seem to do a slow loop-the-loop as they move across the sky
• He used Aristotle’s model and added a small sphere to each celestial sphere to that each planet performed a loop during its circuit
• Ptolemy’s model was accepted for thousands of years as it explained observations and fitted with their religious beliefs that the Earth was the centre of the Universe
Making observations
• In the sixteenth century, Copernicus spent 30 years observing the night sky. He devised the heliocentric model of the solar system which had the sun at the centre
• In 1609 Galileo invented the telescope and more observation could then be made
• A few decades later Kepler used Brahe’s observations to make the heliocentric model better by working out that planets move in elliptical orbits
Astronomy today
• Using telescopes and space exploration, astronomer have gathered more evidence to support Keplers heliocentric model
• This has led to the discovery of hundreds of other planets going around other stars
• In observing the Universe, scientists have discovered other galaxies so more models have been constructed to explain these observation
Questions 4-6
• Scientists now believe that it is gravity that holds planets in their orbit. In Aristotles model what kept planets in their place? (4)
• Why did Ptolemy say his model was better than Aristotle’s? (5)
• Do you think that the belief that heaven is located around the Earth is a belief that began during the time of the heliocentric or geocentric model? (6)
Questions 7-8
• The idea of galaxies as clusters of billions of stars doesn’t feature in early models of the Universe. Use this as an examples to show the link between observations and models. (7)
• If a star has a massive planet nearby, the planet can be detected by a wobble in the stars light as the planet moves around and pulls the star. Why is it harder to detect a small planet orbiting the same star? (8)
Orbits
• The Earth moves around the Sun in its orbit
• The length of the time it takes to do this is called a year
• This takes about 365.24 days so every four years we have a leap year
• Mr Porter was born on this extra day
The Moon
• A satellite is something that goes around a planet (not really)
• The Moon is a natural satellite of the Eart but we also have many man-made satellites
• It takes about 28 days for the Moon to go round the Earth, this is a Month (from Moon)
This was first proposed by______________. It drew on Galileo’s and Copernicus’ claim that_________________________. Newton believed that it was ____________________________. It required the understanding that ____________________________
This was first proposed by… (Newton). It drew on Galileo’s claim that…(the Earth orbits the Sun). Newton believed that it was (natural forces not gods that lead to planetary motion). It required the understanding that… (gravitational forces act through space, the Earth is a sphere).
