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DISPLAYING POSTS FROM: Jun 2011 (14)

Five things about microwaves

Author
by Dr Andi
Publish date
2 June 2011
Comments
Comments (6)

I was reminded by my mother the other day that I had once refused to eat microwaved food. It was the 1970s and I’m not sure if it was teenage rebellion or whether I was spooked by the thought of microwaves. Here are five things about microwaves - some are spooky but some are fascinating.

1. In 1945 Percy Spencer had an “Aha!” moment after a melted lolly. Percy was doing military research on radars when he noticed that the peanut choc treat in his pocket had totally melted. It was the first item of food to ever be microwaved and luckily it was a lab accident that ended well. He realised the goo in his pocket was due to the modified radio waves - or microwaves - that he was working on.

Early microwave oven An early commercial microwave on display at the House Secrets exhibition. This is a 1959 Swedish Husqvarna, Electronic 2001 ‘Cupol’. (I suppose the number ‘2001’ must have seemed like a space age term in 1959).
Image: Andi Horvath
Source: Museum Victoria


2. The mid 1970s became a microwave bonanza and they began selling like hot cakes. Up until then, microwaves had been used in the food industry, restaurants and even submarines. But it wasn’t until the various components, including the new microprocessor, had come down in price and early myths about radiation were dispelled that the commercial domestic market finally took off.

Microwave sales display A salesman looking to make a bonanza of a commission. From the State Electricity Commission of Victoria collection, Museum Victoria. (MM 009529).
Source: Museum Victoria
 

 

3. Microwaves work by jiggling water and fat molecules. A rather unattractive metal box called a ‘magnetron’ is at the heart of every microwave oven; the rest is just insulated casing. The magnetron generates the microwaves that jiggle molecules so fast that they heat up the food.

  Magnetron The magnetron - rather a good name for a super hero or a grunge band, don’t you think?
Image: Andi Horvath
Source: Museum Victoria
 


4. Some things don’t belong in a microwave oven. The House Secrets exhibition at Scienceworks has a display of things not to microwave because it destroys your appliance. We sacrificed a number of microwaves making this film so you don’t have to ruin yours. So don’t try this at home.

Microwave display at House Secrets The video of microwave mistakes is inside a microwave in the House Secrets exhibition. Marshmallow will puff up and then flump, thin metal creates mini lighting (electricity arcs form between the metal and the microwave) and an unpierced egg will explode due to build up of steam.
Image: Andi Horvath
Source: Museum Victoria
 

 

5. Making a tasty gourmet meal in a microwave oven is still a challenge. The pictures in 1970s cookbooks always seem rather unappetising – perhaps the food stylist’s profession was in its infancy. When I asked around the office, most people told me they just use their microwaves to heat things. Perhaps if MasterChef runs a microwave cooking challenge it may inspire people to give it a go.

1970s microwave cookbook Are those chicken skewers with lemon pieces? It doesn’t seem to me to be a microwave thing but maybe that’s why they chose it for the cover: to surprise you. This 1970s microwave cookbook is on display in the House Secrets exhibition.
Image: Andi Horvath
Source: Museum Victoria
 

Bug of the month

Author
by Patrick
Publish date
1 June 2011
Comments
Comments (3)

Welcome to the first instalment of Museum Victoria’s Bug of the Month. At any time, more than 100 species of invertebrates are resident at Melbourne Museum, under the care of the Live Exhibits Unit. These creatures can be seen in Bugs Alive! and the Forest Gallery, and they pop up in other places such as the Children’s Museum and even Amazing Backyard Adventures, currently showing at Scienceworks.

Small Hooded Katydid Face to face with the Small Hooded Katydid.
Image: Patrick Honan
Source: Museum Victoria
 

This month’s bug is the Small Hooded Katydid, also known as Phyllophorella. The name doesn’t adequately describe the large size of this species, which can grow up to 8cm long. Although this katydid has been around for millennia, it was only described by scientists and given an official scientific name two years ago.

Small Hooded Katydid Adult Small Hooded Katydid.
Image: Alan Henderson
Source: Museum Victoria
 

Small Hooded Katydids are found in North Queensland, from around Cairns all the way to rainforest near the tip of Cape York. They are one of the biggest katydids in Australia, but their closest relatives, the Giant Katydids (Siliquofera grandis) are easily the largest, measuring up to 13cm in length.

katydid feeding on broad beans
A katydid feeding on broad bean leaves. If you look closely you can see the katydid’s ear, a small opening located on its foreleg at the left of the photo.
Image: Patrick Honan
Source: Museum Victoria
 

Small Hooded Katydids are vegetarians, feeding on a range of rainforest plants amongst which they are remarkably well camouflaged. Some specimens even have irregular white or brown patches on their wings, which are identical to the spots found on leaves. The veins on the wings also mimic the vein pattern of leaves, so adults can be very difficult to find in the wild. For this reason, they were thought for a long time to be rare, but are actually quite common.

katydid’s wing Close-up of a katydid’s wing, showing the leaf-like pattern of veins and brown spots.
Image: Patrick Honan
Source: Museum Victoria
 

Unlike most other katydids, males of this species don’t call to attract females, so no-one knows how they find each other in the rainforest at night. However, both adults and nymphs can produce a rasping sound when disturbed, by rubbing the bases of the back legs against the body.

Katydid nymph A young nymph living behind the scenes at Melbourne Museum
Image: Patrick Honan
Source: Museum Victoria
 

The ‘hood’ of these katydids, after which they are named, is most obvious in juveniles such as these two below. The pointed spine on each side of the hood is also most prominent at this stage.

juvenile female katydid A juvenile female already bears the sabre-like ovipositor at the end of the body with which she will later lay eggs.
Image: Patrick Honan
Source: Museum Victoria
 

Juvenile katydid feeding A juvenile feeding on organic matter, photographed in rainforest north of Cape Tribulation
Image: Patrick Honan
Source: Museum Victoria
 

Small Hooded Katydids are currently on show in the ‘Enormous Numbers’ display in Bugs Alive! at Melbourne Museum.

Small Hooded Katydid display Small Hooded Katydids in Bugs Alive!
Image: Patrick Honan
Source: Museum Victoria
 

References:

Rentz, D.C.F., Su, Y.N. & Ueshima, N., 2009, Studies in Australian Tettigonidae: The Phyllophorinae (Orthoptera: Tettigonidae: Phyllophorinae), Zootaxa, 2075:55-68

Rentz, D., 2010, A Guide to the Katydids of Australia, CSIRO Publishing, Melbourne, 214pp.

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