Engineering in our class: investigating traffic lights

We have been investigating light and colours.

We have decided to have a close look at traffic lights.

Today at PE we played a game of traffic lights and then we went outside to have a look at real traffic lights.  We were investigating engineering in our local area:

 We discovered some things:

• when the green light shines for cars, then the pedestrian light shines red
• when the red light shines for cars, then the pedestrian light shines green
• the lights turn from green for cars, to orange, then to red.  After red they flash orange (and so do the pedestrian lights!  This means that cars can drive IF there are no pedestrians, but the pedestrians get the right of way first.  After flashing orange the cars get a green light once more.
• We know we can only cross the road if the pedestrian light is green, and must wait on the path if the pedestrian light is red.

We are going to design and make some model traffic lights of our own for art this week!

We have been outside to see traffic lights in operation.

Today we decided to make our own sets of traffic lights.

First of all we talked about the colours of traffic lights, where each colour is placed and what each colour means.  We have learned lots about crossing the road safely, especially with the help of traffic lights.  We can also sing some nice road safety songs.

We have already looked at the sequencing of the traffic lights at our school gate.

Teacher showed us how to fold black paper and then cut semi circles which turn into circles when we unfold the paper.  Cutting out the circles is the hard part.

Next we had to choose some coloured materials for our traffic lights.

We needed the colours red, orange (or yellow if we have no orange) and green.

We also tried various materials to see whether they let the light through (transparent) or blocked all the light (opaque).  We tested this with the light of the projector for the whiteboard.

Felt and coloured sheets of paper didn't work at all because they are opaque.

Crepe paper and tissue paper were a little better, they let a little light through.

Cellophane was the best of all and was extremely transparent.

We used glue to stick on the coloured cellophane and of course we wrote our names on our traffic lights.  Now all we needed was a light source.

We decided to hang our traffic lights on our window and use a natural light source (the sun) to shine through the lights.

Here is what the traffic lights look like on our window.

Our traffic lights also make wonderful shadows on our desks and on the floor (and on Jakub who sits beside the window!)

We are looking forward to designing other traffic lights like these ones made from a toilet roll and coloured tissue!
Look at the traffic lights we made, with no help from teacher at all!