Purpose: To investigate how Porcellio Scaber reacts in terms of orthokinesis to different humidities in their habitat.
Equipment-
75 slaters which range from 5-10mm in length (kept in a plastic container with holes in the lid, with dirt and bark so that they are kept in a natural environment as possible so can react naturally during experiment.)
5x petri dish set ups labelled from 50-90% (One petri dish on the bottom will contain glycerol and have a mesh/gauze hot glued over top for the slater to walk on. On top of this will be another petri dish sealed with blutak to close off the environment.)
5x different glycerol solutions which range from 50-90% humidity (increasing by 10%)
String
Whiteboard marker
Timer
25ml measuring cylinder
Clean cloth …show more content…
After the 10 minutes is up, set a timer to 1 minute and during this time, trace the movement of the slater with a whiteboard marker over the top petri dish.
6. Remove the slater from the petri dish by removing the lid. Place it in a different container so it wouldn’t be reused. Put the lid back on as soon as possible.
7. Use a piece of string to measure the distance travelled by the slater by placing it over the whiteboard marker track of the slater as accurately as possible from start to finish. Mark the distance on the string.
8. Use a ruler to measure the distance marked on the string by laying it out flat. Record this in the data table. This will give the distance travelled by the slater in a 1-minute period. This data can be used in the formula v=d/t (speed of slater = distance travelled / time taken). This will give the average speed of the slater during that time and will therefore give the orthokinesis of the slater used.
9. Clean the whiteboard marker off the lid with a clean cloth. Repeat steps 2-8 another 8 times with the 50% glycerol until 8 accurate distances have been recorded at this humidity. These 8 results will be used to create unbiased data by averaging them