Divide your agar plate into 4 quadrants, A sterile inoculating loop is dipped ito mixed culture, streaked in a pattern over surface of nutrient medium. As pattern transferred, bacteria are rubbed off into the medium. sterilize in between quadrants, the last cells to be rubbed off the loop are far enough apart to grow into isolated colonies. Pick up a colony with sterile loop and transfer into test tube of nutrient medium to form a pure culture containing only one type of bacterium.
Failure to obtain isolated colonies on a streak plate could be due to overcrowding on the plate, improper streaking technique, or contamination of the plate from the environment or the inoculation source. It is important to streak the plate in a way that allows for sufficient separation of individual colonies to form.
You can determine the streak of a mineral whose Mohs scale is higher than the streak plate by either filing or crushing with a hammer before rubbing the sample on a streak plate.
Topaz (8), corundum (9), and diamond (10).
Those minerals that are harder than the unglazed porcelain streak plate will scratch it rather than leave a streak.
The streak left on the streak plate by rubbing a pumice rock usually appears white or colorless. This is because pumice is a light-colored rock composed of volcanic glass with a frothy texture due to gas bubbles trapped in the rock, causing it to create a light streak when rubbed on a streak plate.
No, rubies are too hard to leave a streak. They just scratch the plate.
A streak plate is used to determine the streak colour of a mineral. You take the mineral and scratch it against the streak plate, and it will create a coloured streak on the plate. The streak is not always the same colour as the mineral itself.
The lack of a streak would indicate that the mineral is harder than the streak plate, or the color of the streak is the same as the color of the streak plate.
Diamond will not leave a streak on a porcelain streak plate because diamond is harder than the streak plate. It will leave a scratch on the streak plate for the same reason.
Failure to obtain isolated colonies on a streak plate could be due to overcrowding on the plate, improper streaking technique, or contamination of the plate from the environment or the inoculation source. It is important to streak the plate in a way that allows for sufficient separation of individual colonies to form.
A streak plate is a surface of unglazed ceramic, used to find the true color of a mineral specimen by drawing the specimen across it. The color of the resultant powder is referred to as the streak or streak color of a mineral.
I do not have a picture, but when you scratch aquamarine on a streak plate, the powder will be white colored.
Streak color is determined by scraping the mineral across a a streak plate, (which is made of unglazed porcelain), and then observing the color of the streak, which is left on the plate. Note that some minerals do not leave a streak, as they are too hard. Thus, it is important to learn other identification methods, to use in conjunction with streak color, in order to identify minerals.
Two minerals that do not leave a streak on a streak plate are quartz and fluorite. Both minerals have a hardness higher than that of the streak plate, so they will not leave a streak when rubbed against it.
You can determine the streak of a mineral whose Mohs scale is higher than the streak plate by either filing or crushing with a hammer before rubbing the sample on a streak plate.
The powder left behind on a streak plate is called a streak. It is produced by scraping a mineral sample across the plate to reveal its color and texture. This streak can be compared to a mineral's known streak color to help with identification.
It leaves a scratch instead of a streak because Topaz has a higher number on the Moh's scale compared to the streak plate.