Sunlight and space travel
Supports National Curriculum, Key Stages 1D, 3F, 5E Suitable for years 4,5 and 6. The first sections might be suitable for year 3.
The time for whole session is about 1 hour 30mins. This can be varied by taking shorter paths through the material e.g. by omitting the section on eclipses for younger children or by omitting the sections on shadows for older children. Choices will depend on the particular needs of the school.
Outline of content Aims to establish what the children already know, using demos and class experiments and to build on this knowledge recognise using fun demonstrations that light can be blocked by objects and shadows are formed - then develop this to explain day and night explain with activities that the Sun appears to move across the sky each day and that the effect is caused because the Earth spins on its axis explain that sundials can be used to tell the time and describe the Solar Pyramid demonstrate that the Earth orbits the Sun to use demonstrations and class activities to show that seasons are caused because the Earth is tipped on its axis use fun demonstrations to explain the phases of the Moon encourage the children to explain ‘bad science’ from films use class activities to show that the Moon and the Sun appear to be the same size because they are different distances away explain an eclipse of the Sun using activities and briefly explain an eclipse of the Moon
Points to note: Please read the notes about risks and agree the assessment with the teacher before the session! (Link to safety notes at end of this file) Cross References - The slides in the PowerPoint presentation are referenced in the table. - Apparatus details are below the table and are linked to the relevant sections. (link to apparatus list) - Safety notes are referenced in activities and are listed below the table (link here to list of safety notes) Vocabulary: The presentation uses expressions included in the KS1&2 strategies http://www.standards.dfes.gov.uk/schemes2/science/?view=get
Misconceptions – ie - points that are often misunderstood The Sun and the Moon are about the same size. The Sun moves round the Earth. The Sun appears to move across the sky and then back. In winter the Sun is further away from the Earth than in the summer. The Moon is a source of light. The Moon always shows the same side to the Sun. An eclipse of the Moon is the same as a new Moon.
The session should be held in a room that is not brightly lit. Curtains or slat blinds could be shut but the activities have been planned so that blackout is NOT required as this is difficult to achieve in most primary schools and also might cause behaviour problems.
Activities Discussion Aims/facts 1 Slide 2 The first few slides allows To establish that Ask them what the speed limit is them to discuss their ideas of the Sun is very on a motorway. fast speeds and to try grasp much further away Ask how far they would travel if some understanding of the from Earth than the they were driven at 70mph for 1 distances between the Earth, Moon and both hour and give an example of a Moon and Sun. distances are very nearby city that they might have large compared to reached. Then continue with the Explain that these are thought distances on Earth. idea of the time to drive to a experiments or mental space distant city. Note- the places journeys. named on the slides should be changed for each school. 2 Slide 3 They might point out that the The Moon is a Explain that if it were possible to petrol would run out or the very, very long way drive off to the Moon it would take driver would need food but away from the 140 days if a steady 70mph were explain that it is a thought Earth compared maintained. experiment that overcomes with distances problems. between cities. 3 Slide 4 They enjoy discussing the The Sun is very, Ask them to imagine being driven problems with travelling for very much further all the way to the Sun and ask such a long time. This away from Earth them to guess how long it would emphasises the huge distance. than the Moon. take. They might vote. At 70mph, time taken is about 150 years. (Two lifetimes) 4 Slide 5 + 6 Take the opportunity to point Light moves very, Explain that light travels very fast out that the Sun is a powerful very quickly indeed. The ask them to guess how source of light and heat. through space. long it takes for light to travel from Hazard: they must not look at It takes about 8 the Sun to the Earth. the Sun. See safety notes. minutes for light to travel from the Sun to the Earth. 5 Slide 7 – Point a bright torch Discuss what happens when Light travels in across the room and shake chalk something gets in the way of straight lines dust from a duster in the beam of the light. light so that they can see that light Hazards: Laser pointers should travels in straight lines. not be used and when shaking See apparatus list. the board duster ensure that it is well away from the children. See safety notes. 6 Slide 8 - Shadows (This may be covered quickly Light cannot bend Shadows are formed when some if it has already been studied.) round a barrier. light is blocked out. When light is Show slide 9 without the lower blocked by objects, wording up. Hold your hand in the shadows are projector beam to make shadow formed. shapes on the screen. Volunteers may be able to make animal shapes etc. Show that varying the position of the hand varies the size of the shadow. 7 Game with sheet Stand to one side during the Shadows are See apparatus list. demonstration with the sheet so similar in shape to Ask for two tall volunteers to hold that you can see the class and the objects forming up a large white sheet close to the keep control during this fun them. front row of children. activity. Discuss the changes in Then ask for two more volunteers the shadow as positions to go behind the sheet. One to change. wave arms etc as the second points a bright torch so that shadows are formed on the sheet. 8 Slide 10 Discuss the fact that the part of During daytime the Day and night the Earth with the Sun shining Sun light reaches Hold up an inflatable globe. Ask a on it is in ‘daylight’ while at half the globe. volunteer to shine a bright torch at the opposite side of the Earth it the globe across the front of the is night. During one day the class so that the children can see Compare the diagram on slide Earth rotates once that one side is illuminated and the 11 with the simulation on slide on its axis. other in shadow. Rotate the globe 12 and discuss the fact that, slowly. during 24 hours, the Earth will A day = 24 hours Show slides 11, 12 , 13 move round slowly so that Ask how long it takes for the Earth each part has daylight. to rotate once - 1 day. (Point out that pictures taken from space, like in slide 12, prove that the Earth is a sphere – ie a ball.) 9 Ask for a volunteer who should Ask how long it takes for the The Earth takes stand at the front looking towards Earth to move round the Sun 365 days to orbit the class. Point a bright torch onto once – 1 year. (rotate around) the the child as ask him/her to turn During the discussion ask how Sun. round slowly. Point out that you many times the earth rotates 365 days = 1 year and the torch are acting as the Sun during a whole year. Then ask and the volunteer is the Earth. Ask how many times the volunteer The Earth rotates whether the Earth just rotates or should have spun round whilst 365 times during whether it also moves. Encourage moving round you. (Hazard- the time it takes to the child to move around you – do not allow the child to try to orbit the Sun once. eventually rotating slowly to spin rapidly so becoming dizzy The Earth’s axis is simulate the movement of the and possibly falling.) tipped by 23˚. Earth round the Sun. Point out that the child is standing upright to make a better demonstration the child should lean over at 23˚ to the vertical because the axis of the Earth is tipped. (The word axis might need explanation.) 10 Slide 14 Discuss whether the Sun shines The Sun appears to During the day the position of the in at same place in the move across the Sun in the sky varies. This is classroom during the day. sky in a regular because the earth is turning on its Point out that the pattern of way every day. axis. movement is similar each day. The Sun is highest Slide 14 is animated to show the (The class may have done an in the sky at noon. sun rise then sink in the sky. exercise where they mark the The apparent position of the sun on a movement of the window during a day.) Sun is caused by the spinning of the Earth on its axis. 11 Slide 15 Discuss sundials – often seen Shadows caused by Show the animated slide of the on or by old buildings. the Sun can be used shadow of the stick moving during (Check with the teacher to tell the time. the day. Point out that this can be whether the children have done used to tell the time and the effect a standard activity marking the is used in a sundial. shadow of a stick during a day. If so remind them about it.) 12 Slide 16 Slide 17 Tell them about the plans for the Shows one of the towers of the Solar Pyramid that will be built. huge pyramid which acts a To be built near the M1 in sundial. Derbyshire, England, UK. It (The two secondary arms also will stand 58 metres (over 190ft) have astronomical significance high, making it the worlds’ biggest as one is aligned toward the functioning timepiece! point on the horizon where the Sun rises and the other to where it sets at the time of the Summer Solstice, the longest day of the year.) 13 The seasons Ask whether they notice any In winter the Slide 18 difference in the path of the weather is colder Point out that the Sun shines all sun across the sky during than in summer. year providing light and heat but it winter and summer. They may is colder in winter than in summer. comment that shadows caused Ask what causes this effect? by the Sun generally are longer during winter. 14 Slide 19 In discussion point out that the The Sun rises in the This is animated to show the Sun Sun rises at a point further east East and sets in the rises higher in summer than in and sets at appoint further west West. winter. in summer than in winter The Sun rises (some websites incorrectly higher in the sky in The slide also shows that days are show the sunrise at the same summer than in longer in summer than winter. point on the horizon for winter. summer and winter). Discuss the differences the children notice between summer and winter. 15 Slide 20 Ask what makes it colder in Then slide 20 shows that this is winter than in summer. They because light reaching the Earth may answer that the Earth is during winter is at smaller angle to further from the Sun in winter. the surface ( a greater angle to a It is true that the orbit of the normal to the surface). It is not Sun is slightly elliptical but the obvious to young children why this Earth can be closest to the Sun should result in colder conditions. in January. 16 Demonstration Repeat the demonstration and Extra to KS2: Shine a bright torch onto a dark discuss the effect The seasons are umbrella (see apparatus list) so caused because the that a bright circle of light can be Also the Sun is above the Earth is tipped on seen. Explain that the torch horizon for a shorter time than its axis so that represents a beam of light from the in Summer so the total heat during our Sun and the umbrella, the surface reaching the region is less than summer the earth of the Earth. Point out that during in Summer. The light travels is tipped towards winter the Sun is lower in the sky slightly further through the the sun and during so lower the position of the torch. atmosphere in winter so more our winter, the Change the angle that the light heat is absorbed. Earth is tipped reaches the umbrella so a dimmer away from the Sun. oval of showing that the Explain that the seasons are concentration of heat and light caused because the axis of the reaching the surface is reduced so Earth is tipped by 23 degrees. it is cooler. Point out that during our (See safety notes on spring summer it is winter in the umbrella.) Southern Hemisphere. 17 Game Emphasise that the effect is for Each group should have a torch heat as well as light and and a piece of card or a large discuss the effects if first one brown envelope. They should stands in front of a radiant shine the torch on the card at heater and then stands to one different angles so they see the side. area covered varies with angle- (You are advised NOT to take keeping the distance of the torch a heater into the school. See from the card the same throughout. the apparatus list.) (see apparatus list) 18 Slide 21, 22 In demonstration 1 the ball The Moon is not a Moon does not rotate, which is source of light. The Moon is a satellite of the incorrect. Earth. That means it orbits the A more accurate demonstration The Moon reflects Earth continuously, taking about (2) uses a white ball with a light from the Sun 28 days per orbit. face painted on it. As you to the Earth. The Moon does NOT give out light move round the class, the face but reflects sunlight to the earth. on the ball must always face The Moon takes Demonstration 1 with the ball. the children. The black and approximately 28 Stand at the front of the class and clear cover is slid round so that days to orbit the ask them to imagine that the Sun is the clear part always faces the Earth. shining from the back of the class back of the class and the black so that one side of the ball is part represents the part of the illuminated brightly. Turn the ball Moon in shadow. The changing so that the white side is towards (see the apparatus list for appearance of the the class. Then move towards your details) Moon over 28 days left and stand at the side of the It is not necessary to do both provides evidence class still holding the ball so that demonstrations but repeating for a 28-day cycle. its white side is facing the back of the one you choose will be the class (full Moon). The ball will helpful. The Moon revolves appear half white and half black to once on its axis for the children (last quarter). Then as each orbit of the they watch you move towards the Earth so that the back of the class keeping the white same side of the side towards the back of the class, Moon always faces they will see less and less of the the Earth. white part of the ball until, when you reach the back of the class they see only the black side (new moon). Explain that the Moon takes 28 days to move once completely round the Earth. So your movement so far represents 14 days. Continue to move round so that they see some white and eventually when you are at the front they see the full moon. 19 Slide 23 Slide 24 - They should answer Reinforce ideas. Talk through the animated slide so - the Moon changes appearance that they understand the phases of after a few days. (It only takes the Moon clearly. 7 days to change from a new (Each mouse click moves to anther Moon to a Half Moon.) discussion point.) - the full Moon is so bright that Take the opportunity to answer it is difficult to see stars. questions on slide 24. These are - in a bright room our pupils examples of bad astronomy seen in are contracted so stars are too films. Suggest they watch out for dim to see. examples in films that they see. - refer back to dusk on slide 12. 20 Slide 25 It is best to demonstrate this The sun and the Game first at the front and discuss the Moon look the Hand out a cardboard tube, a small distances before allowing the same size because object and a large object to each groups to try the game. they are different group. One child looks through the distances from the tube and another holds the small Explain that this helps to Earth. object so it appears to fill the understand why the Moon and whole of the end of the tube. The the Sun appear the same size. small object should be moved Refer back to the distances slightly out of line. Then a third discussed at the start of the child should hold up the large session. object and move it so it just Explain that the Sun is very appears to fill the end of the tube. much further away than the The distances should be compared. Moon. They will find that large objects need to be much further from the tube than small ones. 21 Slide 26 During discussion slide 28 will On rare occasions it goes dark in help. the daytime. Game Explain that sometimes the Sun Slide 27 Moon and Earth are not quite They should hold up a circle of in line. Then there is a partial Extra to KS2: cardboard and look at it with one eclipse. These are much more An eclipse of the eye, at a distance so that it just common. If possible tell them Sun occurs when covers the picture of the Sun. when the next partial eclipse the Moon blocks Explain that the card represents the can be seen in the UK. the sunlight from Moon and although it is smaller reaching the Earth. than the picture of the Sun, it blots The last total eclipse visible out the light from reaching their from the UK was seen in eye. Just as the Moon can blot out southern England on 11th light from the Sun reaching us. August 1999. Explain that this is called an eclipse. An animation of an eclipse on 29th March 2006 that was Slide 29 visible as a partial eclipse from Sometimes the Moon is not quite the UK can be seen at in line and a partial eclipse occurs. http://www.eclipse.org.uk/eclip se/0212006/
The next eclipse of the Sun visible from the UK will be on 1st August 2008 and will be seen as a partial eclipse from the UK. 22 Slide 30 Explain that this is different Extra to KS2: Eclipse of Moon from the situation for a new An eclipse of the When the Moon moves into the moon because then the moon is Moon is caused shadow of he Earth it receives no between the earth and the Sun. when the Earth light from the Sun so it cannot be ------blocks the sunlight seen. This is an eclipse of the from reaching the Moon. Moon. Show the animated slide. 23 Take the opportunity to revise using slide 31. 24 Slide 32 The picture shows the space Explain that knowledge about shuttle leaving the international distances and positions of the space station. Earth, Moon, Sun and Planets have Slide 33 shows this enlarged. made space travel possible. Encourage a discussion about the benefits- and whether they would like to be astronauts- point out that many astronauts have studied physics (most have studied science).
25 Slide 34 Link back to the time worked Venetia Burney, when 11 years out to reach the Sun and Moon old, suggested the name Pluto for at 70 mph and explain that the ninth planet when it was space probes travel much faster discovered in 1930. The probe that than that. left to take a closer look at Pluto The probe will visit the Moon early in 2006 will not get there after 9 hours – it took Apollo until 2015 when they will be - - capsules 3 days. As it leaves years old. Jupiter behind it will be Slide 35 travelling at 21 km per second See websites for more information. (13 miles per second). Use the discussion to revise and reinforce their understanding of the large distances and speeds involved. 26 Slide 36 Keep asking questions. There is a lot Finish by pointing out that they more for scientists should keep asking questions – to find out. there is lots for them to find out. BUT there is lots that no-body knows yet and that scientists of the future will be working on and they might be the ones who discover the answers to the puzzles.
Safety Notes During this topic the Sun is discussed. Direct sunlight is not needed in any of the activities. Warn children NEVER to look directly at the Sun. It can cause permanent damage to their eyes. Blindness can result. Tell them that it can burn their eyes because it is so bright. See 'Be Safe' section 13 - available form the ASE http://www.ase.org.uk/htm/book_store/detail.php?SIID=67
Do not allow a child, acting as the Earth, to try to spin rapidly so becoming dizzy and possibly falling.
When shaking the board duster ensure that it is well away from the children. Few children are allergic to chalk dust but it may trigger an asthmatic attack.
Avoid using a spring umbrella that could hurt a child as it opens or give a suitable warning. Open the umbrella away from the children and fold it away as soon as the demonstration is over. Laser pointers are not suitable to replace torches for activities in this presentation as some of them are not safe.
Apparatus Please read the safety notes.
Activity 5 – light travels in straight lines – quick demonstration Powerful torch Board duster with chalk on it
Activity 7 – Game with sheet Large white sheet Powerful torch
Activity 8 - Day and night Inflatable globe – available from websites ~ £3.95 for 30 cm diameter (A football can be used as a substitute for the globe) Powerful torch
Activity 12 - solar pyramid website http://www.solarpyramid.co.uk/
Activity 16 - Seasons: Dark umbrella – (black, brown, dark green--- ) Bright torch Slide 20 - consider beams of light (and heat) from the Sun, reaching the surface of the Earth. During the winter a beam, of a fixed cross-section, reaching the surface of the Earth will be spread over a greater area than a similar beam reaching the Earth in the summer. An umbrella is held first with its surface tipped towards the beam of light from the torch and then tipped away. The torch should be the same distance from the umbrella throughout the experiment because it is not emitting a parallel beam of light. The demonstration could also be used to show that in summer, when the sun is high in the sky, the heat and light is concentrated on the surface - a small bright circle is seen in the demonstration. Then in winter when the Sun is low in the sky, a larger dimmer oval is seen because the heat and light are less concentrated, (less spread out).
A bright circle is seen on the umbrella when it is tipped Beam of light from slide 21 towards the beam of light - as in summer.
Beam of light from slide 21 The patch of light is larger and less bright when the umbrella is tipped away from the beam of light - as in winter. Winter - Sun is low in the sky.
Summer – Sun is higher in the sky.
Understanding statements such as ‘the energy received per unit cross sectional area of the surface of the Earth’ is difficult for all children. This demonstration and slides 19 and 20 explain why it is colder in winter than in summer. Also the Sun is above the horizon for a shorter time than in summer so the total heat reaching the region is less than in summer. The light travels slightly further through the atmosphere in winter so more heat is absorbed.
Activity 17 – Game to explain seasons For each group of about 4 children: Torch Piece of card – A4 or larger You are advised NOT to take a radiant heater into school. It would need a portable appliance test. If one is used, it must have a silica (quartz) sheath over the element and not have a bare element.
Activity 18 – Demonstration 1 of phases of the Moon Football White cloth or white plastic from a bag Black bin bag or black cloth. Adhesive tape Cover the ball so that it is half white and half black
Activity 18 – Demonstration 2 of phases of the Moon White or pale coloured football (if a white ball is not available then paint a ball or cover it with white plastic.) Marker pen Clear plastic (bag) – cut a circle with diameter = half circumference of ball Black plastic bin bag Strong adhesive tape Use a maker pen to draw a large face on one side of the white ball. Make a sliding cover: Use the adhesive tape to stick the black plastic round the edge of the clear plastic circle. Shape the plastic over the ball and draw the black plastic loosely to keep the cover on the ball. Cut a hole to allow your hand to hold the ball.
Adhesive tape fastening clear and black plastic but not touching ball
White ball with face on it Black plastic gathered to form handle.
Clear plastic gathered round one side of the ball and stuck to black plastic
Activity 20 – Game to explain that apparent size varies with distance For each group of about 4 children: Cardboard tube from a kitchen roll or similar Small object about 10 cm across -- or a child’s fist Larger object about 30 cm in across
Activity 21 – to explain eclipse of Sun Circles of card about 8 cm in diameter – enough for at least 1 between 4.
Activity 25 - Pluto probe More details on web eg at http://space.newscientist.com/article.ns?id=dn8587&feedId=online-news_rss20 http://www.washingtonpost.com/wp-dyn/content/article/2005/12/18/AR2005121800976_2.html