Shadows

A fun, interactive and challenging science day designed to investigate the concept of shadows. The day was created for a year one year group however it could be adapted for any year group or class.

 Aims

To understand how shadows are created.

To be able to describe whether materials are opaque or transparent.

To be able to ask simple questions and perform simple tests.

To be able to gather and record data to help answer questions.

To use observations and ideas to suggest answers to questions.

 

Overview of the day:

15 minutes – Whole class/year input

Start the day with the room dark and the projector light shining onto a white screen. Tell the children you are going to be spending the day exploring science. Then look behind you confused and ask the children whether they can see the weird black shapes on the board like you can…ask if anyone knows what they are?

At this point the scientist should enter the room (another teacher dressed up as a scientist). The scientist should introduce themselves and tell the children that they have heard that there are some amazing scientists in the room and they really need their help. Discuss how in the school they have started to see these black things appearing behind people and objects and no-one knows what they are. The school have called the scientist in to investigate, however the scientist is really busy so needs the children to help them. Can the children in the room help the scientist? They need to find out what the black things are? And if they change/can they be changed? Once children have agreed to take on the challenge the scientist should tell them he will be back at the end of the day to hear from them and then leave.

Talk to the children about how they could create a hypothesis and then test it…what could the hypothesis be? Give the children time to talk in talk partners and then discuss their ideas before creating a hypothesis similar to this:

Solid/dark things create shadows and clear things let light through.

Draw a Venn diagram on the board and explain that throughout the day you want them to come and add to the diagram. They need to put a tick in the yes circle if they see solid/dark things create shadows and clear things let light through, a tick in the middle if they see a bit of both and a tick in no if they see clear things make shadows and solid/dark things let light through.

 

2 hours – The children will then move through a rotation of activities. They will spend 30 minutes on each activity. Each activity should be supported by one or two adults depending on whether a class or year group science day.

Dark Room 

Resources: dark area, puppets (finger puppets/hands/paper shape on a stick)

Set up an area of the classroom to be a dark room using black material. There will be a light source inside  the dark room. The children can use their hands as puppets, paper on a straw or finger puppets to create shadows. Discuss what the black shapes on the wall are i.e. shadows, talk about why they are there and the different shadows that can be made using different shapes. Encourage the children to try and change the shadows, ask them to predict what they are going to see before testing out their ideas. Talk about the difference in the size of the shadows if the children have their puppets close to the light source or further away. Why does the size and the shape change?

Teacher notes: shadows are created because light cannot pass through an object as the object is opaque. Therefore the area on the other side of the object that the light cannot pass through is black. A shadow will get bigger as the object is moved towards the light source as less light can get past the object as it is closer to the light. A shadow will get smaller as the object is moved away from the light source as more light can get past the object as it is further away from the light.

Light and dark experiment

Resources: torch, sugar paper and pen for the floor book, materials (mirror, wood, paper, plastic etc.)

The children will be given a box of materials. They will also be given a torch. Discuss what they could test? What is their hypothesis? How are they going to test each material? How are they going to record the findings? What is their conclusion?

Discuss the terms opaque/transparent. Ask the children to help you look these words up in the dictionary and then work out which materials show which properties. Record their questions, methods and findings in a floor book. Take pictures for their books, the floor book and displays.

Teacher notes: opaque means not being able to see through it / light not being able to pass through it, transparent means being able to see through it / light being able to pass through it. If something allows light through but you cannot see detailed objects then it is called translucent. 

Black box and moving shadow experimenting

Resources: pencil, Plasticine, paper, torch, black boxes and materials from around the classroom

To create a black box cellotape the lid of a shoe box shut so it is completely enclosed. Then cut a hole in the end of the box for someone to look through. Next cut a flap on the lid at the other end of the box to the eye hole so that the flap can be completely closed to create total darkness or opened to create different degrees of light. 

To set up a moving sun experiment stick a pencil onto some Plasticine in the middle of a piece of A3 paper. Then shine the torch onto the pencil from different angles and look at the different ways that the shadow falls on the paper. Get the children to have a go at shining the torch and discuss the different shapes, length, size etc of the shadows. Ask the children to draw around the pencil’s shadow when the torch is being held at different positions. Talk about how this is similar to the sun and how the torch is the sun in this experiment. Discuss how and why the shadows change. Once you have done this a few times ask the children to predict what they think will happen and then test their predictions to determine the result.

Teacher notes: the pencil’s shadow will be on the opposite side of the paper to the torch. The shadow occurs because the light cannot pass through the pencil as it is opaque. The pencil’s shadows shape will change if the torch is moved up/down. If the torch is held over the top of the pencil (at a high height) then the pencil’s shadow will be shorter as less of the pencil blocks the light. In contrast if the torch is held in line with the paper or lower down the pencil’s shadow will be longer as more of the pencil blocks the light. If the torch is held directly above the pencil then there will be no shadow as the light can get to every part of the paper except for the part which the pencil is stuck onto so it looks like the pencil has no shadow. This is what happens with the sun; our shadows are short when the sun is high in the sky and longer when the sun is lower in the sky. 

Also set up some black boxes so that some of the children can be doing this whilst the others are working on the sun experiment with you. The children should use the black boxes to explore shadows and the difference between what you can see in the light and dark…talk to them about the difference between when the light hole is open and when it is closed. Can they see shadows in the light? How much light is needed to see the outline of shapes or the colour of shapes?

Teacher notes: the children will not be able to see anything when the box is closed however as they open the flap they will see the outline of the object and then as they open it further the colour of the object and then when fully open they will see the details of the shape. This is because our eyes need light to determine the features of an object as our vision works by bouncing light of objects. Our eyes work increasingly better the more light we give them. 

Laptops (this could be independent) 

The children will explore videos/games about shadows. These websites will be up on the laptops and the children will be told that they need to stay on the links already open.

http://www.bbc.co.uk/schools/scienceclips/ages/7_8/light_shadows.shtml

http://www.bbc.co.uk/bitesize/ks2/science/physical_processes/shadows/play

 

15 minutes – Whole class/year evaluation

Bring the children back together. Show them the Venn Diagram and ask them what the diagram shows them – does it prove or disprove our hypothesis. Then ask the children to share a few examples of what they saw during the day that proved or disproved their hypothesis.

Finally ask the children to show you thumbs up if they enjoyed the day and thumbs down if they didn’t enjoy the day. Ask different children to share what they enjoyed and what they would have changed.

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