springs for year 9 prac
springs for year 9 prac
Dear All, new textbook for earth science topic shows build your own seismograph. Science Focus 3 - it shows a spring suspended from a rod on a retort stand. Where would I purchas springs with a bit of give in them but not too much - in fact where can I get any springs at all ? thanks Sue
Hi Louis
Yep you can get these springs, I use the Hook's Law springs to do this one (SSA Cat 1918-001, $19.20 EACH). i use an old 200-500gm reagent bottle with a felt pen inserted (and filled with sand)as shown in the book. I then put 2 holes in the lid to allow a loope of wire through the lip to hook the spring to. But what they don't tell you is that the pen will move around, so I use a "u" tube made of cardboard or metal to hold the pen lightly incontact with the paper and at the right angle. The "u" tube and pen-weight is then placed around 30 deg. not 90deg (or square on to the paper) as it will get stuck. This allows the pen to stay stationary and not twist around while the kids bang the table etc. and record the oscillations recorded on the paper.
Its works but not as well as a bought device which cost mega bucks. Requires some practise and a bit of skill on the kids behalf.
Kim
Yep you can get these springs, I use the Hook's Law springs to do this one (SSA Cat 1918-001, $19.20 EACH). i use an old 200-500gm reagent bottle with a felt pen inserted (and filled with sand)as shown in the book. I then put 2 holes in the lid to allow a loope of wire through the lip to hook the spring to. But what they don't tell you is that the pen will move around, so I use a "u" tube made of cardboard or metal to hold the pen lightly incontact with the paper and at the right angle. The "u" tube and pen-weight is then placed around 30 deg. not 90deg (or square on to the paper) as it will get stuck. This allows the pen to stay stationary and not twist around while the kids bang the table etc. and record the oscillations recorded on the paper.
Its works but not as well as a bought device which cost mega bucks. Requires some practise and a bit of skill on the kids behalf.
Kim
