In our initial experiment, we tried to find the wavelength of the microwave. After repeating our experiment for many times, our results are not constant. So we started to doubt that the standing waves may not be as simple as we think—they mightpossibly be several three dimensional waves which are very hard to visualize. It is not possible to always get a distance of six centimeters between two burnt points, such a case has been repeated by many people in their videos online. We started to doubt the reliability of the videos although they can
always get the correct answer for wavelength of light. After consulting our teacher mentor, we concluded that the standing waves inside are 3 dimensional. Also we decided to try to map out the 3 dimensional waves by putting different materials inside.
* The bases can be
rotated to raise the agar to a higher level. For example the
2cm x 20cm x 0.8cm acrylic base support can be
the 20cm x 2cm x 0.8cm acrylic
Meaning it can raise the agar gel 2cm above or 20cm above.
f)Pure powder agar gel (swallow globe brand)
To make agar gel
Step 1: Pour 5g of powder agar gel and add
500ml of cold water
Stir constantly in the wok until it boils
To study the microwave in the microwave oven
using agar gel
Step 3: Pour the cooked agar gel into the
acrylic mould and allow it to cool and harden
Step 4: Put the mould into the oven by using
the 2cm x 20cm x 0.8cm acrylic base to support it. Turn it to medium power and
heat it for 2.5 minutes.
Step 5: Record the results
Step 6: Repeat steps 1 to 5 with the rest of
the acrylic base support listed in b.
The purpose of this experiment is to discover
the different patterns the microwave oven makes at different heights. In this
way we can find the shape of the 3 dimensional microwave by stacking all the
layers of the different height up. Since the oven have a height of 21 cm, and
the height of the mould is 1cm, the highest it can go will be 20cm.
1.Continuing with the steps in the experiment,
we went on to raising the acrylic tray up to 18cam and 19cm. The agar gel
couldn’t be raised to 14cm and 16 cm as the microwave have a bump in the 14cm
and 16cm mark that looks something like this:
Hence we can’t align the tray properly due to the bump as
it would be slanted, affecting out results. Therefore we skipped both of the
height for now. We would be making a smaller acrylic tray for the next batch of
After repeating all the experiment steps for all the
experiment, clear plastic sheets were used to mark out the hot spots.
Analysis of this set of data: This batch of experiment is
not reproducible as the experiment when repeated were not consistent. For
example when repeated the experiment by raising the height of the agar to 10 cm
in height, the dark spots appeared somewhere else. This is not a good sign as
it meant that the results are not reproducible as they are not consistent. The conclusion is the material we used may
not be that suitable in the experiment.
The results were also plotted onto a graph:
The distances are spread over a large range, which shows that the experiments are not reproducible as the spots were randomly found.
Asthe agar gel experiment is not reproducible another material must be used to replaced them. We have come out with a few materials to replace the microwave oven:
May not work as it would be hard to measure the
distance between two spots
b)Crayon As it is made from wax, it does not absorb
microwaves. Lead shavings can solve the problem. So far we have not tried it.
c) Hair gel Hair gel absorbs microwave and it turns into a
shade of darker pink when placed in the microwave.
The small blob
of gel was pale pink but the big blob of gel which is placed in the microwave
oven changes from pale pink to pink
The results were also
quite consistent. After conducting a trial experiment for a few times (readings
were not recorded), the spots on the hair gel was found approximately on the
same location( without smoothing the bumps but was left to cool)
we re- smoothened the gel, the spots were found on different locations.
This may be due to uneven spreading.
To ensure that
the hair gel is spread properly, we would be using a big acrylic sheet of
dimensions larger than 26 cm by 26 cm to smoothen the bumps on the hair gel
tomorrow. We will continue to put the hair gel into the microwave oven
Does not work as it will catch fire when placed
in the microwave oven.
This idea hasyet to be tried out
f)water + yeast + flour
This idea has yet to be tried out
If c doesn't work, we would be trying out
on a, c, e, f